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1
7th and 8th November 2012
East Midlands Conference Centre,
The University of Nottingham
CONFERENCE PROCEEDINGS
ukpassivhausconference.org.uk
Proceedings Editor
Lucelia Rodrigues, University of Nottingham
Conference Steering Committee
Mark Gillot, Conference Chair, University of Nottingham Jon Bootland, Passivhaus Trust
Frances Bradshaw, Anne Thorne Architects
Bill Butcher, Green Building Store
Nick Grant, Passivhaus Trust
Christina Hopfe, Cardiff University
John Lefever, Hastoe Housing Association
Sarah Lewis, bere:architects
Henrietta Lynch, University College London
Kym Mead, BRE
Sofie Pelsmakers, University College London Robert Prewett, Prewett Bizley Architects
Lucelia Rodrigues, University of Nottingham
Melissa Taylor, Passivhaus Trust
Anne Thomas, sustainableBYdesign
Paul Tuohy, University of Strathclyde
Proceedings of the UK Passivhaus Conference 2012 | Version 2 - 06.11.12
© BRE & Passivhaus Trust
Disclaimer
None of the contributors, sponsors, administrators or anyone else connected with the BRE, the
Passivhaus Trust, the University of Nottingham or the conference steering committee can be responsible for the appearance of any inaccurate or libellous information, or for your use of the information
contained in these pages. The BRE and the Passivhaus Trust disclaim liability for any loss which may arise
from any person acting in reliance upon the contents of this document.
Front Page Image: Wimbish Passivhaus, courtesy of Parsons + Whittley
3
ABOUT THE CONFERENCE
Passivhaus buildings provide a high level of occupant comfort while using very little energy for heating and cooling.
They are built with meticulous attention to detail and rigorous design and construction according to principles
developed by the Passivhaus Institute in Germany, and can be certified through an exacting quality assurance
process.
Over 30,000 Passivhaus buildings have been built in Europe and interest in Passivhaus is growing in the UK, with at
least 150 units either certified or in progress.
The conference exists to spread learning between all those who are interested in the field of low energy building
design in the UK. It includes case studies, site visits, workshops, debate, an exhibition of Passivhaus products and
numerous networking opportunities.
The conference offers a comprehensive review of the uptake of Passivhaus in the UK covering the standard, its
suitability in the UK, leading edge case studies and practical delivery of the first Passivhaus projects in the UK. The
conference will focus on themes such as retrofit, local economic added-value, residential and non-residential
buildings and occupant comfort/measured performance.
The first day will examine policy, regulations and projects, including talks from leading national and international
speakers. The second day will focus on technical seminars covering costs, procurement, design, supply chain and
other important issues.
The UK Passivhaus Conference 2012 was organised by the Passivhaus Trust and BRE, together with their
supporting partners and affiliates.
CONFERENCE PROGRAMME
The first day examines policy, regulations and projects, including talks from leading national and international
speakers. The second day focus on technical workshops and seminars covering costs, procurement, design, supply
chain and other important issues.
Day One - Wednesday, 7th
November 2012
09:00 Registration
09:30 Chair's welcome and opening address
09:50 Session 1: Plenary- Passivhaus & Policy
11:30 Session 2: Plenary- Passivhaus - Learning Journeys
14:00 Session 3: Breakouts- Detailed Case Studies
a. Large scale residential
b. Non-residential
c. Self-build & Refurbishment
d. Tour of Saint Gobain Nottingham H.O.U.S.E
16:10 Session 4: Breakouts- Process
a. Technical detailing 1
b. Evidence & feedback
c. Supply chain
17:40 Debate: 'Passivhaus & Design creativity'
18:30 Drinks & Networking - Start of the ‘Spot the Difference - Live!’ experiment
20:00 Conference Dinner
Day Two - Thursday, 8th
November 2012
09:00 Registration
09:30 Chair's welcome
09:50 Session 1: Plenary- Key UK Research
11:30 Session 2: Breakouts
a. Detailing 1
b. Software, modelling & PHPP
c. Retrofit case studies & feedback
13:45 Session 3: Breakouts
a. Technical Detailing 2
b. Modern Methods of Construction (MMC)
c. Domestic new-build case studies & feedback
d. Tour of Saint Gobain Nottingham H.O.U.S.E
15:30 Session 4: Breakouts
a. Climate & weather data
b. Performance monitoring
c. Larger scale case studies
17:00 Final Plenary Session: What have we learnt that will help to deliver Passivhaus at standard costs?
17:45 Results of the ‘Spot the Difference - Live!’ experiment
18:00 Close
18:30 Private view of exhibition: Prototyping Architecture at the Energy Technologies Building, University of
Nottingham Innovation Park
5
TABLE OF CONTENTS
The contents of the proceedings have been organised in alphabetic order by author surname. All extended
abstract received were added to this document, which may be updated in due course.
ABOUT THE CONFERENCE ............................................................................................................................................. 3
CONFERENCE PROGRAMME .......................................................................................................................................... 4
TABLE OF CONTENTS ................................................................................................................................................... 5
SPECIAL FEATURES ..................................................................................................................................................... 7
Spot The Difference – Live! ..................................................................................................................................... 8
The Saint Gobain Nottingham H.O.U.S.E. ................................................................................................................ 9
EXTENDED ABSTRACTS ............................................................................................................................................... 11
Alex Amato, Simon Law, John Bryant, And Ahmad Al-Abdulla ............................................................................. 12
James Anwyl, Nina Mader ..................................................................................................................................... 14
Marion Baeli, Jean Pierre Wack ............................................................................................................................. 16
Jane Barnes, John Lefever ..................................................................................................................................... 18
Justin Bere ............................................................................................................................................................. 20
Daniel Boughton .................................................................................................................................................... 22
Helen Brown .......................................................................................................................................................... 24
Helen Brown .......................................................................................................................................................... 26
Alan Budden .......................................................................................................................................................... 28
Elrond Burrell ......................................................................................................................................................... 30
Toby Cambray ........................................................................................................................................................ 32
Michael Crilly, Mark Lemon ................................................................................................................................... 34
Tom Dollard ........................................................................................................................................................... 36
Richard Dudzicki .................................................................................................................................................... 38
Mila Durdev ........................................................................................................................................................... 40
Lee Fordham, Nick Grant ....................................................................................................................................... 42
David Gale, Tomas Gärtner ................................................................................................................................... 44
Tomas Gärtner ....................................................................................................................................................... 46
Jonathan Hines, Lars Carlsson ............................................................................................................................... 48
Ben Hopkins ........................................................................................................................................................... 50
Martin Ingham ....................................................................................................................................................... 52
Simon Jesson ......................................................................................................................................................... 54
Haniyeh Mohammadpourkarbasi, Steve Sharples ................................................................................................ 56
Sarah Lewis ............................................................................................................................................................ 58
George Mikurcik And Jonathan Hines ................................................................................................................... 60
Francis Moran, Sukumar Natarajan, Andy Shea .................................................................................................... 62
Johnathan Nea ....................................................................................................................................................... 64
John Pratley, Paul Smyth ....................................................................................................................................... 66
Jim Shaw ................................................................................................................................................................ 68
Mark Siddall, David Johnston ................................................................................................................................ 70
Ruth Sutton, Chris Herring ..................................................................................................................................... 72
Kim Williams .......................................................................................................................................................... 74
Andrew Yeats......................................................................................................................................................... 76
CONFERENCE DELEGATES ............................................................................................................................................ 78
7
SPECIAL FEATURES
SPOT THE DIFFERENCE – LIVE!
How does the performance of a Passivhaus building compare to one built to Part L building regs in reality? Church
Lukas, Saint Gobain, Factory Homes and GB Building Solutions, with the support of University of Nottingham, have
come together to demonstrate just that.
We have built 2 student bedrooms - one to Part L 2006 specifications and the other as close as possible to the
Passivhaus standard. Over the 2 days of the conference, volunteers will live in these bedrooms and the energy
consumption of the rooms will be tested. The results of which will be shared at the final session of the conference.
Church Lukas were selected as market leaders in student accommodation to design the two pods due to their
experience with offsite construction and knowledge of sustainable student accommodation. The two rooms are
designed to replicate one of the rooms in an innovative new student townhouse model.
Saint-Gobain was chosen to supply the construction materials for the pods due to the quality and breadth of its
product range. The comprehensive nature of its offer is illustrated by its ability to supply all the solutions needed
to construct the pods, with their performance and efficiency demonstrating how sustainable living can be achieved
using products and systems that are commercially available today.
Factory Homes were selected due to their industry leading manufacturing skills. The two rooms were constructed
entirely in their factory allowing extra care and attention over the details of the Passivhaus room in order to
ensure maximum possible performance. The two rooms were then transported to site highlighting the ability of
offsite construction to minimise the time needed on site and perform within tight programmes.
GB Building Solutions were chosen due to their experience and reputation of delivering high quality sustainable
student schemes. They are the only contractors in the world to achieve a BREEAM outstanding student scheme.
The project is supported by the University of Nottingham who will be carrying out the testing and analysis of the
two rooms during the conference and presenting the results on the final day in order to assess the performance
difference in reality between the two standards.
Contacts: Thomas Simmons ([email protected]), Russell Davison ([email protected])
Lucelia Rodrigues ([email protected]) and Lindsey Walker ([email protected])
9
THE SAINT GOBAIN NOTTINGHAM H.O.U.S.E.
The Saint Gobain Nottingham H.O.U.S.E (Home Optimising the Use of Solar Energy), designed and built by students
at the Department of Architecture and Built Environment at the University of Nottingham, was the only UK entry
competing against nineteen other Universities from around the globe at the final of the International Solar
Decathlon Europe Competition, held in Madrid during June 2010. In Madrid the HOUSE picked up the prestigious
‘Sustainability Award’. The international jury commended the team for designing a truly sustainable house that is
market-ready and market-appropriate. Just before that, in March 2010, it was exhibited at Ecobuild, London, the
world’s biggest event for sustainable design, construction and built environment, where it won the ‘Timber at
Ecobuild Award’. The home is now in its final place at the Green Close on the University Park campus, as part of
the Creative Energy Homes project.
Delegates have the opportunity to go on guided tours of the HOUSE during both days of the conference.
Contacts: Mark Gillott ([email protected]), Lucelia Rodrigues ([email protected])
and Lindsey Walker ([email protected])
Find out more at www.creative-energy-homes.co.uk or www.facebook.com/CreativeEnergyHomes
11
EXTENDED ABSTRACTS
7 t h and 8 t h of November 2012
EMCC, The University of Nottingham – Nottingham, UK
12
THE DESIGN AND MODELLING OF QATAR’S FIRST CASE STUDY
PASSIVHAUS
The influence of a hot arid climate on the concept of the Passivhaus building envelope
ALEX AMATO, SIMON LAW, JOHN BRYANT, AND AHMAD AL-ABDULLA
Head of Sustainability, Qatar Green Building Council; [email protected] +974 6688 6040
Associate Director Building Engineering AECOM UK. [email protected] +44 (0) 1727 535947
Associate Professor, Texas A&M University - Qatar Campus [email protected] +974 4423 0133
Deputy Group CEO, Barwa Real Estate , Qatar [email protected] +974 4499 0876
Background
Barwa Real Estate (BRE) are constructing the first Qatar Case Study Passivhaus, which is scheduled to be
completed in time for the COP 18 UNFCCC conference, in Doha late November early December this year. Barwa
are one of the major developers in Qatar involved in all types of development, both within and outside of Qatar,
and are keen to redefine the ‘standard Qatar villa’ along much more sustainable lines. Directly along side the
Passivhaus a similar house is being constructed to act as a ‘business as usual’ control for the experiment.
The energy and water consumption, together with the comfort conditions (temperature, relative humidity and air
movement) within each house will be monitored over at least a year during which the houses wil be inhabited by a
three or four person family. BRE are seeking to limit the anticipated increase in capex of the Passivhaus to less
than 15%.
Climate
Qatar’s climate is often considered to be the antithesis of the UK’s climate. Hot arid, versus cool and damp
climatic conditions sum up these countries’ respective climates, but this does mask some interesting similarities,
especially so for residential new build where the preeminent building typologies of both the UK and Qatar are very
similar in form - two storey detached villas and houses. Moreover, for residential new build, villas and houses it is
external climatic conditions that drive the Passivhaus design in both countries rather than internal heat loads.
Both countries also experience a period of three to four months when the climatic conditions are sufficiently
clement that little or no energy input is required to maintain internal comfort conditions. Although, the method of
achieving internal comfort for the majority of the year in each country is diametrically different, cooling in Qatar
and heating in the UK, it is interesting to conjecture that the energy loads devoted to maintaining internal comfort
in each country might be very similar. If so it would demonstrate the robustness and wide global applicability of
the Passivhaus concept while potentially revealing what the most effective universal technical strategies are.
The climate in Doha, Qatar’s capital and largest city can be considered an extreme hot arid climate. There are
however periods in the late summer when the humidity can be extremely high; this coupled with high ambient
temperatures makes the external conditions particularly uncomfortable. Here are some notable points of Doha’s
climate.
� Peak dry-bulb temperatures of ~45ºC
� 50% of the time the external dry-bulb is greater than 26.5ºC
� 15% of the time the external dry-bulb is greater than 35.0ºC
� Natural ventilation only feasible for around 4 months of the year
� During summer months (June to September) average external dry-bulb temperature is around 33.5ºC while
relative humidity averages around 43%
� Annual global solar irradiance is almost double that of the UK.
13
Engineered Solution
It was therefore essential to apply the core Passivhaus principles of super insulated envelope (external insulation
to minimise thermal bridging) and minimising the air permeability, so as to de-couple the internal environment
from the extreme climate outside. The very low air permeability of the envelope requires the use of a whole-
house mechanical ventilation system with heat recovery, where air is supplied to the bedrooms and living space,
then extracted out of the bathrooms and kitchens. Solar gain is also minimised by the use of triple glazing with
high performance solar control glass (BS EN 410 g-values of around 0.2). As the energy to condition incoming fresh
air is substantial, the fresh air supply rate is kept to minimum levels recommended by ASHRAE (~50 l/s based on
continuous ventilation). In addition, the whole house mechanical ventilation system has efficient heat recovery of
around 90%.
Figure 1: Annual Range of Temperature and Humidity in Doha, Qatar
In practice cooling is required for at least 80% of the year, so in order to minimise and simplify the controls, the
cooling system and ventilation system runs continuously. This works in synergy with the exposed thermal mass, to
minimise the capacity of the cooling plant required. Cooling is provided by two DX units, one serving the living
space which is open plan and includes the kitchen, while the other is ducted to the bedrooms with return air via
the shared hallway. The total cooling capacity required for the house is around 7.5kW based on continuously
operation.
Ideally the cooling and ventilation would be provided by a single central air handling unit, but due to the small
capacities required, there is currently no off-the-shelf equipment that would meet the requirements, which is why
cooling is provided by DX units.
Conclusion
Building to the Passivhaus specification means that for Qatar there is no requirement for space heating, and the
key issue is dealing with the cooling load caused by internal and solar gains. To meet the challenge of building in
extremely hot/humid climates, Passivhaus have introduced a new limit which takes into account the latent
requirements of the local climate, which for Qatar takes the cooling limit from 15 to around 23 (kWh/m² per year).
Detailed simulation of the proposed house has shown that this limit is within reach provided performance of the
envelope, HVAC, and lighting systems is pushed to the limits of what is currently readily available.
7 t h and 8 t h of November 2012
EMCC, The University of Nottingham – Nottingham, UK
14
COMPARISON OF LIFE CYCLE RESULTS OF PASSIVHAUS BUILDINGS WITH
DIFFERENT CONSTRUCTION METHODS
JAMES ANWYL, NINA MADER
Eurobuild, [email protected], Eurobuild, [email protected]
In January 2012, Eurobuild were awarded 2nd
place in the BRE UK Passivhaus design competition and ‘Commended
for Innovation’. Eurobuild were project partners on the technical and production side to AH3 architects and the
competition required Eurobuild to carry out a Life Cycle Assessment (LCA) on the design. Subsequently, the carbon
footprint of a residential Passivhaus building was assessed, and the impact of the following construction types
were compared:
a) Imported ‘closed’ timber frame panels (typical Austrian construction)
b) Open timber frame (typical UK construction)
c) Masonry (traditional UK brick & block construction)
The functional unit was defined as the lifecycle of a two-unit house built to Passivhaus standard. The building has a
total treated floor area of 239.9 m2 over 3 storeys. Each unit occupies 1.5 storeys of the building. The location of
the building is BRE Watford.
The assessment was carried out using PAS2050: 2008, with a focus on the five key principles established in the
standard: relevance, completeness, consistency, accuracy and transparency. The full lifecycle of the building cradle
to cradle is included within the system boundary. A screening LCA was used to identify key emissions sources and
also identify processes that have low materiality and so can be excluded. Data were selected using a data quality
scoring process, considering time-coverage, geographical specificity, technology-coverage, accuracy and precision.
Full sources for all data used can be made available on request.
The building envelopes of the imported Passivhaus and the standard timber frame structures are made
predominantly of wood or wood-based materials, and even in the masonry version, there are timber-based
materials included, e.g. the roof structure. As such, there is a carbon credit for the absorption and storage of
carbon in the materials. Any subsequent release of this stored biogenic carbon, once the building has been
demolished, is assumed to be outside of this product system because the organic material can be recycled or used
in a waste-for-energy process in a new product system.
However, in order to assess the potential impact of any timber and paper sent to landfill, an alternative scenario
was also taken into account. This is based on current recycling figures in demolition projects as a worst-case
scenario, that recycling methods won’t change at all within the next 60 years. Based on current DEFRA statistics, a
split between recycled material to material sent to landfill in demolition projects can be assumed to be 74%:26%.
Hence, in the alternative scenario, 26% of paper insulation and timber are sent to landfill and produce greenhouse
gases in the decaying process. This greenhouse gas has been taken into account.
Four different ‘end-of-life’ scenarios were developed during the course of this study:
1) Timber for UK from Sweden, 74% timber & paper insulation recycled
2) Timber for UK from Latvia, 74% timber & paper insulation recycled
3) Timber for UK from Sweden, 100% timber & paper insulation recycled
4) Timber for UK from Latvia, 100% timber & paper insulation recycled
15
The main focus is on the first two scenarios as they represent worst case; scenarios 3 and 4 have been completed
as well as they are believed to be the more likely scenarios. The GHG benefit of using wood-based materials is
clear, particularly in the imported Passivhaus and traditional timber frame model, from the large negative raw
material number. This carbon is stored in the building over its 60-year lifetime. The model assumes two scenarios:
either the wood is then re-used or burned in a waste-to-energy converter. In this case, the negative impact of the
stored carbon returning to the atmosphere does not feature in this product system (scenarios 3 and 4); or the
timber and paper based materials are only partially recycled (scenarios 1 and 2).
The origin of the timber used in the timber frame and roof construction for the traditional models (i.e. either
Sweden or Latvia) has a very minor impact on the results. With the timber coming from Latvia, the overall carbon
footprint only rises by less than 1% compared to the Swedish example. Therefore, further analysis focuses on the
results relating to Swedish timber examples, scenarios 1 and 3.
Raw materials transportation is small but relevant. For the imported Passivhaus structure, the main part of this is
transport of the building envelope from Austria, whereas for the timber frame model, the main part is for the
timber transport from abroad. Transport from local suppliers is ±9% of the total transport for these models, and
makes up 35% for the masonry model. Transportation of the boiler and MVHR from Germany is negligible.
In construction, electricity use in site tools is the main emissions source making up about 50%, with the other 50%
originated from diesel use in the telehandler, crane and welfare unit, as well as team transport to site. This is the
same picture for all three construction methods.
The overall carbon footprint is dominated by the use phase. The use phase itself consists of natural gas use and
electricity demand from the building. Electricity grids are expected to decarbonise over the next 20 years, thus
electricity use in maintenance and demolition will increasingly be zero carbon. This means that the emissions
relating to the demolition of the building in year 60 is negligible. Transportation of the waste materials post-
demolition is accounted for but also small, in the context of the overall footprint.
Despite being imported from Austria, the closed panel Passivhaus structure is calculated to have the lowest
resulting carbon footprint, 12% less than a traditional UK timber frame building of the same size and shape and
36% less than a masonry version of the same building.
This is mainly due to the carbon storage of a system that is almost exclusively timber, with less metal in assembly
and smaller concrete foundations required in construction. This carbon benefit is large enough to compensate for
the whole impact of transport, construction and demolition.
Figure 1: Closed timber frame wall panel produced in Austrian factory
7 t h and 8 t h of November 2012
EMCC, The University of Nottingham – Nottingham, UK
16
PASSIVHAUS VS. DECENT HOME PLUS AND
STANDARD UK HOUSE POST OCCUPANCY EVALUATION
MARION BAELI, JEAN PIERRE WACK
Paul Davis + Partners [email protected]
This paper will present a comparative monitoring data results for three similar Victorian houses in the same street.
One that has been retrofitted to PassivHaus standard (1st fully certified in the UK), one to Decent Homes Plus
standard (50mm insulation and secondary glazing) and one where no energy savings measures have been installed
at all called ‘Standard UK.. All three houses are in the same street, were built at the same time and made of the
same materials. They are also of very similar layout overall. The PassivHaus and Decent Homes Plus are adjacent
and facing West-East while the ‘Standard UK’ is facing East-West on the opposite side of the Road. The monitoring
data analysed in this paper is for a whole year of post occupancy and is looking at energy consumption, internal
temperatures, relative humidity and CO2 concentration. All three properties are the ownership of Octavia Housing
who have kindly supported this monitoring programme.
Final Energy Demand
The monitoring analysis of Final Energy Demand in the three houses highlighted huge savings for both the
PassivHaus and the Decent Home Plus compared to the Standard UK house (not retrofitted). The Final Energy
demand (i.e. energy that is supplied to the consumer for all final energy uses) for the PassivHaus added up to 63
kWh/m2/year as against 198 kWh/m
2/year for the Decent Home Plus and 366 kWh/m
2/year for the typical scheme.
This yields a 83% reduction for the PassivHaus and 46% for the Decent Home Plus compared to the Standard UK
house. The Princedale PassivHaus considerably exceeds the PassivHaus standard for Final Energy Demand, set at
120 kWh/m2/yr. During the most energy intensive month (February 2012), Final Energy savings reached 88% for
the PassivHaus and 52% for the Decent Home Plus, due to dramatic increase in the typical scheme space heating
demand. Those results demonstrate the very good performance of the PassivHaus building envelope in terms of
energy efficiency through a both very low and stable Final Energy consumption. Due to unexpected monitoring
problems, the Space Heating Demand share was not monitored during this first year of occupancy. However, it is
likely to considerably overcome the maximum PassivHaus requirement of 15 kWh/m2/yr.
The reduction in CO2 emissions resulting from the building energy consumption for overall operations and services
is 70% for the PassivHaus (which sizeable despite the fact that the dwelling only uses electricity, which is more
carbon intensive than main gas, used for space and water heating in the two other monitored properties) and 37%
for the Decent Home Plus compared to the Standard UK house baseline.
Reduction of Final Energy Demand also enable the families to reduce the risk of finding themselves in a situation of
fuel poverty, from which 4 millions households (particularly in social housing) suffered in 2010. The yearly energy
bills add up to £770 per year in the PassivHaus while the Decent Home tenants are charged £1,470 per year. Year
monetary savings as a consequence of energy efficiency measure are £1,255 per year in the PassivHaus as a direct,
and £550 per year for the Decent Home Plus. In addition, the family have been given advices to be able to further
reduce its energy bills by another £150 by changing payment method to Monthly Direct Debit, and potentially
switching to the cheapest energy supplier of Princedale Road.
The payback period is the estimated time required to recover from the upfront cost invested in the energy
efficiency measure on site through savings in energy bills only. The total cost of energy saving measure for the 88
m2
PassivHaus was £87,478 and £13,074 for the Decent Home Plus, which explains the gap in the expected
payback period. Assuming a 10% yearly increase in fuel prices as a reasonable assumption based on the
Department of Energy and Climate Change fuel prices statistics, the payback period is expected to be 28 years for
17
the PassivHaus and 16 years for the Decent Home Plus. However, monetary payback of the PassivHaus project is
expected to overcome those of the Decent Home Plus in only 33 years time.
Thermal Comfort and Indoor Air Quality.
The sizeable costs of energy efficiency measure in the PassivHaus also yields considerable improvements in terms
of thermal comfort and Indoor Air Quality. The yearly average temperatures in occupied rooms is 22.1°C in the
PassivHaus living room and 19.4°C in the typical scheme living room. The improvements in thermal comfort are
even more sticking during the peak winter week in February 2012, during which the average temperature in the
PassivHaus is 20.8°C, which is 4.4°C more than in the typical scheme living room. Moreover, this level of thermal
comfort is achieved using 88% less energy. Those results hold, to a lesser extent, for the Decent Home Plus.
The PassivHaus presents good levels of Indoor Air Quality (CO2 concentration of 620 ppm and 50% Relative
Humidity). Peaks in CO2 concentration and relative humidity are controlled much more efficiently in the PassivHaus
that in the two other schemes. For instance, relative humidity peak (when % RH goes above 60%) is 3 times more
frequent in the Decent Home than in the PassivHaus. Moreover, CO2 concentration and relative humidity
regulation in the typical scheme living room is only achieved by natural ventilation and air infiltration, which
sizeably contributes to the building heat loss. On the other hand, MVRH provides good CO2 regulation in the
PassivHaus, while both contributing to heating the house in the winter and providing cooling in the summer.
Other monitoring results, suggest that living in a PassivHaus (and to a lesser extent in a Decent Home Plus)
encourages the occupants to actually live in a more sustainable way, beyond the main objectives regarding Final
Energy Demand, Thermal Comfort and Indoor Air Quality. For instance, water consumption is the PassivHaus is 85
Litres per person and per day, against 200 Litres in the Standard UK house.
Figure 1: Princedale Road view of the PassivHaus and Decent Home Plus (nex
Summary of Key results Typical Scheme Decent Home Plus Passivhaus
Primary Energy Demand (kWh/m2/year) 366 198 63
% reduction vs. Typical scheme - 46% 83%
CO2 emissions (tons/year) 7.8 4.5 2.3
% reduction vs. Typical scheme 37% 70%
Expected Energy Bills (£/year) £2,026 £1,468 £772
Savings vs. Typical Scheme £559 £1,255
Cost of energy efficiency measures - £13,074 £87,478
Payback Period - 16 years 28 years
Average Temerature in the living rooms 19.4°C 20.2°C 21.1°C
Average C02 concentration (ppm) 650 N/A 620
Average % relative humidity (%) 53% 56% 50%
Water consumption (Litres/person/day) 195 137 85
7 t h and 8 t h of November 2012
EMCC, The University of Nottingham – Nottingham, UK
18
PASSIVHAUS LEARNING JOURNEYS
Learning from Large Scale Residential Developments
JANE BARNES, JOHN LEFEVER
Davis Langdon, An AECOM Company, [email protected]
Hastoe Housing Association, [email protected]
‘Passivhaus’ remains a relatively new concept within the UK construction industry, particularly its use on larger
scale residential developments; as such, harnessing lessons learnt from those projects which have been through
the process and achieved the standard is imperative to encouraging the use of Passivhaus on a larger scale within
the UK construction industry.
Hastoe Housing Association and Davis Langdon have worked together to successfully deliver two residential
Passivhaus developments in South East England; Wimbish Passivhaus and Ditchingham. Wimbish is fully accredited
by the Passivhaus Institute and Ditchingham is completed with an application for accreditation currently being
prepared.
This presentation discusses the key lessons learned through experiences on both projects but refers primarily to
the Wimbish scheme, focussing on design, procurement, construction, on site management, occupation and
maintenance. The intent of the presentation is to share knowledge and experiences to inform Passivhaus
development moving forward and for the benefit of other Passivhaus developers, designers and contractors.
The primary learning point derived from the design stage of the Wimbish project was the importance of
developing the design holistically, considering architectural, structural and mechanical and electrical designs in
conjunction with each other thus ensuring the ‘whole’ house could be modelled in the Passivhaus Planning
Package software as the design was developed. This gave the team the comfort that the detailed design would
achieve the Passivhaus standards. A key component of this process was the requirement for all team members to
fully understand and believe in the concept, and that the end goal of Passivhaus accreditation was at the forefront
of all decisions.
Procurement of both projects was challenging given the level of design detail required and the limited experience
of UK contractors in Passivhaus construction. Hastoe’s approach was to use a bespoke design and build route
whereby their design consultants developed the detailed design to Stage F, following which the project was
tendered using a multi-stage process. The Wimbish project benefited from Hastoe retaining their design
consultants to monitor the works post-contract whereas consultants were novated on the Ditchingham scheme.
The experience of both approaches has resulted in Hastoe’s preference to retain their consultants on projects
moving forward.
Construction presented many challenges and the presentation focuses on the main issues and how these were
overcome, as well as ‘what worked well’. Subcontractor training and the ability to maintain a fully trained
workforce throughout the duration of the project were problematic and detailed consideration of both issues
during early engagement with the contractor proved essential.
The Wimbish project benefitted from the installation of monitoring equipment (funded by the TSB) and a two year
monitoring programme, undertaken by the University of East Anglia (UEA). To date, the findings of this study have
proved invaluable to analysing how the dwellings perform when occupied and how resident behaviours influence
dwelling performance. The overall conclusion is that residents are happy with their new homes and have benefited
from reduced space heating bills. There are lessons to be learnt in relation to resident and maintenance team
support / education as well as the potential for dwellings to overheat which could suggest alternative orientations
to ‘North-South’ may be better suited to the UK climate.
19
One of the main barriers preventing the construction of Passivhaus developments on a larger scale, particularly for
large commercial house builders is that there is no uplift in the value of the property to reflect the inherent
benefits of Passivhaus dwellings (reduced running costs etc.). This, coupled with the fact that there is still a cost
premium associated with the standard, gives commercial developers little incentive to construct to Passivhaus. The
link between value and benefits associated with highly sustainable, energy efficient buildings needs to strengthen
to encourage development of Passivhaus on a larger scale.
Figure 1: The Wimbish Passivhaus development, Essex
7 t h and 8 t h of November 2012
EMCC, The University of Nottingham – Nottingham, UK
20
THE PASSIVHAUS COST PROJECT (PHPP)
A project update
JUSTIN BERE
bere:architects, Mildmay Centre, Woodville Road, London N16 8NA, tel: +44 (0)20 7241 1064
Introduction
The Passivhaus Cost Project is a collaborative research project lead by bere:architects. It was launched in
September 2011 with the purpose of establishing a standard cost reporting protocol; sharing cost information
amongst the collaborators; and establishing a blueprint for affordable passivhaus homes. The project has a
particular focus on rented social housing.
The project aims to widen the debate about affordability by differentiating between capital and whole life costs
and it aims to establish economical but high quality methods that will enable housing providers to deliver all the
benefits of the passivhaus standard.
Method
(1) Research and document the cost-models used by the established ‘Private for Sale’ (PFS) house builders in
building their minimum-standard building regulation houses.
(2) Ditto, but adjusting the housebuilders’ designs to meet the 2016 zero carbon compliance standard.
(3) Consider the potential to reduce both capital costs and whole-life costs in a basic passivhaus home of
equivalent size.
(4) For each of the above, investigate the capital and whole life costs as one-offs and at scale.
Results
A standard detailed cost reporting protocol has been produced and will be presented for discussion. Commercial
sensitivity about true costs continues to hinder the collection and publication of useful figures, and a great deal of
work remains to be done, but the author suggests that when the cost of building materials is separated from the
cost of labour, it is easy to imagine the potential for reducing capital costs by increasing workforce skills and
integration. Modern tendering methods have been inclined to create contracting methods which prioritise the
search for the lowest subcontract prices. This has a tendency to run counter to a culture of building quality and
retaining skills. Perhaps it is now time for clients and design teams to re-consider the commercial, capital and
lifetime cost benefits of delivering modern methods of construction by collaborating with traditional contractors
who build and retain skills, from apprentice to site manager, within a valued and directly employed, integrated,
collaborative labour-force? Perhaps by this means, passivhaus teams can bring together the advantages of
increased build quality and lower construction costs?
21
7 t h and 8 t h of November 2012
EMCC, The University of Nottingham – Nottingham, UK
22
STANDARDS & PERFORMANCE RELATING TO ROOFLIGHTS FOR
PASSIVHAUS PROJECTS
Passivhaus certified phA roof glazing components
DANIEL BOUGHTON
Daylight & Ventilation Solutions Ltd, [email protected], 01284 749051
Passivhaus represents one of the most stringent standards in energy efficiency in modern construction. It is
regarded as the world’s chief energy efficiency standard for new buildings and building refurbishments. This is
because passive houses dispense with separate heating systems and make use of existing energy in buildings to
provide heating instead. In order to comply with this requirement, Passivhaus planners rely on high-grade, energy-
efficient quality construction materials which retain the maximum possible amount of energy inside buildings and
provide an extremely airtight building envelope, thanks to their certified insulation properties.
Lamilux has just been provided with conclusive proof that its glass roof structure CI System Glass Architecture PR
60 (PR60) features such characteristics. This glass and aluminium system has recently been certified by the
Passivhaus Institute in Darmstadt, Germany, as the first sloped glazing component suitable for passive houses. The
aesthetically pleasing daylight system with its customisable shape achieved top marks and was assigned to the
Advanced Component phA category.
In accordance with Passivhaus requirements, the technical conditions provided in the newly certified system
consistently allow glazing to be used which comprises three panes with Argon gas filled cavities. Two of these glass
panes feature a low-e coating. The “warm edge” with Super Spacer forms a spacer system. The U value, or heat
transmittance coefficient, in the 52mm glazing specification (Ug) is 0.72 W/(m²K) when installed in an inclined
position.
Figure 1 shows the newly developed insulation system for mullion and transoms, consisting of a combined
impermeable core which unites the insulation block and the insulation web in a single component. The material
used in the system makes the supporting structure twice as energy efficient. The heavy load from the glazing
elements is absorbed by the glazing support, aided by glazing fastening bolts, while mullion and transoms feature
very low heat transmittance coefficients of 0.79 W/m²K.
The Passivhaus Institute in Darmstadt established a UCwi value of 0.8 W/(m²K) for the daylight system as a whole. A
good heat transmittance coefficient is one of the main criteria for successful certification and must be under 1.00
W/(m²K) for sloped installation in roofs.
Assessors attach great importance to other aspects when it comes to assuring compliance with Passivhaus
requirements with hygiene playing a significant role. In order to prevent condensation and mould growth, the
12.6°C isothermal line must consistently lie within structures at an outside temperature of -5°C, an indoor
temperature of +20°C and a relative humidity of 50 per cent. The PR60 complies with this requirement.
Heat loss is another factor; this is calculated for the frame system and the ‘warm edge’, and expressed by the
coefficient ψopak. The lower this value is, the higher the efficiency class. In the case of PR60, the coefficient is lower
than the maximum value of 0.110 W/(mK) for PassivHaus classification in the phA – Advanced Component class.
“With its PR60, Lamilux has managed to bring onto the market the first mullion and transom system in the Inclined
Glazing category,” state assessors at the Darmstadt-based Passive House Institute. This provides energy and cost-
conscious architects and planners with the first ever glass roof solution which is not only suitable for Passivhaus
constructions, but also complies with requirements for the top Passivhaus efficiency class phA.
23
Figure 1: The PR60 has an innovative insulation system making the system twice as energy efficient.
7 t h and 8 t h of November 2012
EMCC, The University of Nottingham – Nottingham, UK
24
A DETAILED REVIEW OF AIR BARRIER DESIGN AND
IMPLEMENTATION IN DOMESTIC RETROFIT
58 Elliott Drive, Orbit Heart of England, the 2nd
certified EnerPHit project in the UK
HELEN BROWN
Encraft, [email protected], 01926 312159
The air tightness target is a particular challenge for Passivhaus retrofit projects and in recognition of this the
EnerPHit requirement for the pressure test result is relaxed slightly from <0.6h-1
to <1h-1
at 50Pa. Although slightly
easier, the target is demanding and surpasses the requirements for new build projects under current UK Building
Regulations. Placing the emphasis on the N50 (units h-1
), rather than the Q50 (units m2/(m
3h)) means that the target
is especially challenging for buildings with a high surface area to volume ratio i.e. very small buildings such as social
housing, or buildings with an inefficient shape or form factor.
The approach to air barrier design and implementation at 58 Elliott Drive, the 2nd
certified EnerPHit project in the
UK was comprehensive. A detailed air tightness strategy and specification document was developed during the
early stages of the design. This was a collaborative effort between the architect and Passivhaus consultant and it
was issued alongside the tender specification and architectural drawings through contract instruction to the main
contractor. The document contained information on strategies chosen for the air barrier including drawings and
detailed descriptions. Details were fully developed for potential weak points including junctions between building
elements and penetrations from service pipes etc. The intention was to provide guidance to site operatives
responsible for quality control or site supervision, and a direct reference for those responsible for implementing
the details. Products were specified explicitly, along with guidance on sequencing. Also in the document, the target
pressure test was clearly stated as were the requirements for pressure testing, including interim testing and leak
detection recommended to check progress.
The project was fortunate to benefit from the experience of two site operatives (Chris and Steve) who had
previously worked on another Passivhaus-inspired retrofit project by Orbit Heart of England; Foleshill Road in
Coventry. The pressure test result at Foleshill Road was around 1.5h-1
which made Chris and Steve determined to
achieve a better result at Elliott Drive. The experience they took from Foleshill Road meant that they were familiar
with the approach and products and were able to suggest improvements and revisions to the strategy and
specifications, using their preferred choice of product where appropriate. They were also able to communicate the
importance of maintaining the integrity of the air barrier to other members of their team and also to
subcontractors. Although not formally nominated as such, they were air tightness champions in the truest sense of
the word.
The property was pressure tested before work commenced onsite and achieved N50 = 8h-1
. This was a relatively
good starting point, exceeding the current regulatory requirements for new buildings in the UK. It was thought
that the solid ground floor, together with the internal plaster finish and external cement render to walls, all
contributed to the relative air tightness of the pre-retrofit building.
A decision was made early on to utilise the internal plaster finish as the air barrier in the walls. This was considered
to be the easiest, most cost effective solution to implement, utilising a traditional skill-set and hopefully ensuring
longevity in the lifetime of the air barrier. The existing plaster layer was retained where possible, however there
were many areas requiring repair that were identified using a leak detection kit. There were also areas requiring
treatment that had not been plastered previously, such as the strips hidden behind internal walls or behind joists
in the intermediate floor and areas in the attic which was brought inside the thermal envelope following the
addition of a new attic truss warm roof. The plaster layer had to be joined to the air barrier in the new ground floor
25
slab which was the DPM underneath the insulation layer, and the air barrier in the new roof, which was the
membrane on the external side above the insulation layer. A useful product, half tape and half mesh was used to
aid implementation of these joins where the mesh side was embedded in the plaster layer to ensure integrity and
longevity in the join. This tape-mesh was also used around the window and door installations to seal frames into
the wet plaster in the internal reveals.
Possibly the greatest challenge for Chris and Steve was to bring membranes past timbers, both in the roof at the
rafters close to the eaves and around the intermediate floor where joists were supported on the party and gable
walls. This work was awkward and time consuming as each and every joist was sealed to the membrane with tape.
The leak detection kit identified a particularly weak point in the gap between a double joist in the intermediate
floor.
The new attic truss roof was implemented by a specialist contractor with no experience of aiming for Passivhaus
air tightness standards. A double sided butyl tape was applied along the length and on top of each roof rafter prior
to the application of the membrane. This enabled an air tight seal formation around each of the many nail
penetrations required to fix battens on top of the membrane. Leak detection was carried out soon after as there
were some concerns about the number of nail penetrations and uncertainty as to whether the butyl tape would
seal adequately. However almost no leaks were detected which is a good testament to the performance of this
particular product. Other products which performed well were the rubber grommets used for the cable and
service pipe penetrations.
Once the project neared completion a full pressure test was carried out, achieving N50 = 0.98h-1
. A great result all
considered and just within the limiting target for EnerPHit. However, the criteria for certification requires that leak
detection and remedial work is carried out when the value N50 = 0.6h-1
is exceeded, even if <1h-1
is achieved first
time around. Therefore, following leak detection and remedial work the subsequent and final pressure test result
was N50 = 0.53h-1
, surpassing even the requirements for new build and leading to confirmation of the EnerPHit
certification for this successful project.
Figure 1: 58 Elliott Drive Wellesbourne, the 2nd
certified EnerPHit in the UK, a collaborative project with Orbit Heart of England Housing
Association (client), Encraft (Passivhaus consultant), ID Partnership (architect) and Property Matters (main contractor)
7 t h and 8 t h of November 2012
EMCC, The University of Nottingham – Nottingham, UK
26
A DETAILED ANALYSIS OF THERMAL BRIDGES, DESIGN AND
IMPLEMENTATION IN DOMESTIC RETROFIT
58 Elliott Drive, Orbit Heart of England, the 2nd
certified EnerPHit project in the UK
HELEN BROWN
Encraft, [email protected], 01926 312159
Detailed analysis of thermal bridges is necessary for all EnerPHit projects in order to ensure accuracy in the
thermal model. Additionally the adoption of thermal bridge-free design principles is a criterion of EnerPHit
certification. In order to comply, the thermal building envelope should have no linear thermal bridges with Ψ >
+0.01 W/(mK), or punctiform thermal bridges with χ > +0.04 W/K. However in retrofit projects it is often
uneconomical and/or impracticable to implement thermal bridge-free detail formation and instead the approach
must be to diminish the thermal bridge as far as possible. The aim is to provide both thermal and moisture
protection by the elimination of cold temperatures on interior surfaces of the thermal envelope.
Fifteen thermal bridge coefficients were included in the final thermal model (PHPP) of 58 Elliott Drive in
Wellesbourne, the 2nd
certified EnerPHit project in the UK, two of which were punctiform. Four out of the fifteen
did not comply with the requirements of thermal bridge-free detail formation, despite being diminished as far as
practicably possible. However, other coefficients exceeded the requirements which in a way compensated for
those that could not be diminished sufficiently.
Results from thermal bridge calculations fluctuate with changes to insulating materials and thicknesses. Any
seemingly small change to a detail could have a significant effect on the end result and it could take time to
remodel the revision. In recognition of this, the approach taken at Elliott Drive was to design around an assumed
value for the contribution towards the total building heat loss of all thermal bridges (excluding the window and
door installation, treated separately). This made it possible to define the final specification for the retrofit before
thermal bridge coefficients were fully calculated.
During the early stages of the design, time was invested in reviewing each thermal bridge qualitatively (without
modelling) with a view to diminishing each as far as possible, usually using extra “flanking” insulation to cloak any
area where there was a break in the insulation layer. A strategy for each detail was developed collaboratively by
the architect and Passivhaus consultant. Nevertheless there were a number of modifications as the project
progressed. Some changes arose because of practical issues, raised by operatives once onsite. Others because the
initial sketch drawings were based on approximated dimensions rather than accurate measurements.
Recalculation of some thermal bridge coefficients was therefore unavoidable.
Some aspects of the thermal bridge analysis seemed counterintuitive. Linear thermal bridges which appeared
insignificant made more of an impact on building energy performance than first expected when they were applied
over a long length. This was especially true for thermal bridges around the perimeter and the window and door
installations. Conversely, punctiform thermal bridges are dimensionless and had limited impact. Thermal bridges
associated with the ground floor slab are particularly difficult to understand intuitively due to complexities in the
thermal model of the ground. And measures considered involving internal wall insulation reduced the treated floor
area, increasing specific space heating demands, despite a diminished thermal bridge.
For the case of the window and door installation, the default value in the PHPP of Ψ = 0.04W/(mK) was assumed.
The default can be used if it is clear from the drawing that it is thermal bridge free. The window manufacturer
assisted with the detailed design, where windows and doors were positioned inside the insulation layer using a
timber bearer at the base (and at door jambs) and metal straps at the head and the jambs. The window
27
manufacturer also provided some accurate calculations for the thermal bridge coefficients which indicated an
average of Ψ = 0.004W/(mK) was likely with the implemented detail. However, these calculations were not in the
format required by the certifier for verification. In the end this was not critical because the building still complied
with the EnerPHit criteria even with the default assumed. Had the calculated coefficient been used instead, the
specific space heating demand would have been reduced by 1kWh/(m2a) or 4% of the target. By comparison, the
initial proposal drawn up by the architect included aluminium flashing, which is often a standard detail in
traditional construction with external wall insulation. If this detail had been adopted the thermal bridge coefficient
would have been closer to Ψ = 0.4W/(mK) and this would have increased the specific space heating demand by
22kWh/(m2a) or 88% of the target.
Other thermal bridges of interest were in the ground floor slab at the junctions between load bearing internal and
party walls. The existing floor was excavated to make room for an insulated slab and the internal wall removed at
ground floor level to enable insertion of a load bearing thermal break before the wall was rebuilt. This approach
was not possible for the party wall, however, the adjoining dwelling was retrofitted at the same time to a lesser
extent and here the original solid ground floor slab was retained with no insulation. The resulting model indicated
that heat was being transferred to the EnerPHit property from the adjoining dwelling via the thermal bridge in the
ground floor slab at the party wall.
The PHPP thermal model is based on a degree day analysis using u-values and areas derived from external
measurements. The inclusion of calculated thermal bridge coefficients fine-tunes the model, making it more
accurate. When external measurements are used for areas there will be sections (e.g. at corners) that are double
counted and here the calculated thermal bridge coefficients will be negative (i.e. they will reduce the calculated
heat loss), assuming thermal bridge-free design principles have been adopted. In the final thermal model of Elliott
Drive the summed contribution towards total building heat loss of all thermal bridges was negative. This means
that the fine-tuning in the model due to the inclusion of thermal bridge coefficients actually served to reduce the
calculated heating demand from what it would have been if all coefficients had been omitted. This is the situation
one would expect for a new build project and thus demonstrates the success of the approach taken.
Figure 1: 58 Elliott Drive Wellesbourne, the 2nd
certified EnerPHit in the UK, a collaborative project with Orbit Heart of England Housing
Association (client), Encraft (Passivhaus consultant), ID Partnership (architect) and Property Matters (main contractor)
7 t h and 8 t h of November 2012
EMCC, The University of Nottingham – Nottingham, UK
28
HOW WE ACHIEVED PROBABLY THE
MOST AIRTIGHTNESS HOUSE IN THE UK
(N50= 0.07 h-1 @ 50 Pa)
ALAN BUDDEN
Eco Design Consultants, [email protected]
Airtightness is a vital component of the Passivhaus strategy with a requirement of 0.6 Air changes per hour at 50
Pascal’s, the average taken from both a positive and negative tests (blow & suck). This requirement though
measurable is the most difficult to achieve as it relies on onsite workmanship, and quality of almost all trades.
The recently completed Howe Park Wood Passive House, and certified Passivhaus on the edge of Howe Park Wood
in Milton Keynes achieved an airtightness of N50= 0.07 h-1 @ 50 Pa. This we believe is the most airtight house in
the UK. The house is timber framed with an internal air barrier formed of 18mm OSB3 and Pro clima tapes, but
also has an air barrier on the outside formed with Agipan T&G DWG boards, a breathable wood fibre board with
wax coating and sealed with butyrub a non setting mastic.
The Airtightness strategy started with simple detailing and keeping the air tightness layer as simple as possible.
The Howe Park Project used traditional platform construction and so to join the OSB airtightness layer on the
ground floor to the first floor walls a pro clima air tightness membrane was used rapping around the first floor
joists.
Forming the airtightness layer on the outside is an easy option as the boards are easily accessible to ensure good
joins and the risk of damage from internal fit out is eliminated. However careful consideration of moisture through
the structure is needed as the internal airtightness membrane often also acts as a vapour check membrane to
ensure that the structure remains dry and condensation free. It is important that the vapour check is continuous
and well sealed. Tests have shown with a 1m x 1m piece of insulated wall with a vapour check installed when a
1mm by 1m slit is made in the vapour membrane the U value reduces by 4.8 times. These gaps in the vapour
check not only reduce the thermal performance but also allowing moisture into the structure. It is therefore
advisable that the airtightness layer is installed on the warm side of the insulation, acting also as the vapour check.
As this is probably the most airtight buildings in the country, the question of what happens if the MVHR breaks
down has been raised and how long will it take for the occupants to suffocate. The Loss of Oxygen is not the
problem; the more dangerous outcome is that the CO2 levels may increase to dangerous levels. This however will
not happen if the windows are opened. The air will become stuffy and the occupants will wish to open a window.
It is widely recognised that only when CO2 concentration of over 5% is toxic to health. At 2% it becomes noticeable
with symptoms of a heavy chest or increased breathing (20,000 parts per million). At 5% breathing will be 4 times
normal rate, at 7.5% headache, dizziness, sweating, restlessness and disorientation will occur at and only over 20%
deaths have occurred.
However, if we assume that the house is completely airtight and no air changes are taking place, the volume of the
air in the house is approximately 490m3 and the maximum occupancy is 9, that is 54m3 per person. To take the
worst case scenario and the person is doing heavy work/ exercise the body’s carbon dioxide emissions are upto
0.038m3/h so in 1 hour the concentration of C02 could rise by 0.07% so after 24 hours that would be an increase
of 1.7% which may be noticeable by the occupant, and they would probably wish to open the window or go
outside! If all the occupants were working at this rate constantly for over 2 days then the levels could rise above
the 5% but the chances of this and the occupants not noticing that the MVHR is not working and not going outside
29
or opening a window are remote. If however you do have a concern CO2 meter/ alarms can be purchased that
sound an alarm when the CO2 levels increase and so action can be taken.
The airtightness strategy, used on the project included red line drawings, showing where the air barrier was, which
could be the OSB, concrete slab, window or airtightness tapes. It is important that site inductions are given to all
operatives working on site so that they all understand the need for airtightness, where the barrier is and how it
functions. A no blame culture is also encourage, if a hole is made in the air barrier by mistake, if it is bought to the
attention of the supervisor then it can be taped up, and put right, a hole left however could be difficult to find
later. Using as simple as possible details is also useful in ensuring that airtightness tapes can be easily fitted and
are functional particular at difficult junctions at the first floor level, foundations, eaves, window & door openings
and service penetrations.
In conclusion, a high airtightness is good for reducing energy consumption, is not a health risk and is best achieved
with an airtightness layer on the inside of the insulation, to reduce moisture risk in the structure. To achieve a
good level of airtightness attention to detail is need by all involved.
Figure 1: Howe Park Passive House, Milton Keynes by Eco Design Consultants Ltd.
7 t h and 8 t h of November 2012
EMCC, The University of Nottingham – Nottingham, UK
30
BUILDING INFORMATION MODELLING FOR PASSIVHAUS
ELROND BURRELL
Architype Ltd, [email protected]
This presentation will address the following questions - What is “BIM” and why does it matter? How can BIM be
used in the passivhaus design process and what are the benefits?
Building Information Modelling
"BIM", variously understood to be Building Information Model, Building Information Modelling or Building
information Management, has become a buzz phrase in the UK construction industry, since last year’s Government
Construction Strategy mandated fully collaborative 3D BIM (aka “Level 2 BIM”) as a minimum on all government
projects by 2016. This is primarily because the government sees BIM as a way to achieve a 20% reduction in both
cost and carbon emissions.
“Building Information Modeling is the process of generating and managing information about a built asset over its
whole life.” Cabinet Office
BIM is about developing and interrogating an information-rich 3-dimensional building model, coordinated between
different disciplines, so that the right information is available at the right point in the delivery process –
theoretically from design and construction through to facilities management, maintenance, future alterations or
refurbishment, etc. This 3-dimensional collaborative process facilitates better resolution of potential construction
issues at the design stage, reducing cost, waste, and reworking, and it helps to close the gap between design and
performance. It is, in a sense, a design led quality assurance process.
For a design consultant, this means getting into more sophisticated modeling software than 2D or 3D CAD. In BIM
software a virtual building is created with construction components, elements and materials and specification
information all included. The 2-dimensional drawing outputs are then “cut” from the 3-dimensional model, so that
live geometry and material/specification information is displayed. This often appears to result in an increased
pursuit of whimsical, complex, difficult to build forms, an increased production of seductive digital imagery and an
increased reliance on reassuring numbers that appear as if by magic from the inaccessible depths of the software
(or more recently “the cloud”.) However, these outputs are mostly a distraction from the rigorous passivhaus
design process.
BIM for Passivhaus
Architype have been developing the use of BIM in the design process using Autodesk® Revit® software for over 5
years. As Architype increasingly design buildings to the Passivhaus standard and used PHPP as a design tool they
have focussed on developed techniques to utilize BIM to support the rigorous Passivhaus design process. The key
areas that Architype have focussed on are visual interrogation of the building information model and efficient
production of accurate numerical data. In terms of the former, Architype have focussed on techniques to use the
3d model to analyse the thermal envelope, the airtight line, the total heat loss area and inter-disciplinary model
coordination. (Using models from the structural & M&E consultants.) In terms of the latter, Architype have focused
on techniques to produce accurate live numerical data for Treated Floor Area, ventilation volumes, total building
volume, heat loss areas and window opening areas.
The key benefits of utilising BIM in the Passivhaus design process have been through greater understanding and
resolution of designs, a reduction in duplicate working, and greater productivity.
Demonstration
31
The second part of the presentation will compromise a demonstration of the techniques discussed above on a
small project using Autodesk® Revit® BIM software.
Figure 1: Using a 3d model to analysing the thermal and airtight line
7 t h and 8 t h of November 2012
EMCC, The University of Nottingham – Nottingham, UK
32
A COMPARISON OF PHPP AND
TAS DYNAMIC SIMULATION SOFTWARE
TOBY CAMBRAY
Greengauge Building Energy Consultants [email protected] 07709170008
Questions are often raised regarding the comparison of PHPP, a steady-state building energy simulation tool, with
dynamic simulation tools such as TAS. Contrasts can be made between the detail of input, the assumptions
underlying the methodology and the ease, or skill necessary to produce reliable results. This paper compared these
two tools, in terms of input requirements, calculation methodology, results obtained and type of outputs. The key
differences in the tools were discussed, and a simple rectilinear building was simulated in both and the results
compared. Finally, the results from a live project were compared.
The methodology of TAS has some interesting differences with that of PHPP. As a dynamic simulation tool, it
calculates a heat balance for each zone, for each hour of the year, compared to PHPP which considers the building
as one zone, and calculates a heat balance for each month. The inputs to TAS for the simulation such as weather,
occupancy patterns and thermostat settings, are defined for each hour of the year. A significant difference
between TAS and PHPP is that the former can take into account zones within the building, which may have
different exposure to solar gain and internal gains from equipment etc. As such TAS is better equipped to estimate
how buildings with a variety of different activities will perform in terms of comfort conditions. Finally, TAS can
allow the temperature to float up and down (and calculate this temperature), whereas PHPP assumes a constant
temperature, usually of 20°C.
As such, TAS is able to produce more sophisticated outputs. Virtually any heat flow to or from a zone can be
extracted from the results, and information such as temperature profiles and overheating frequencies can be
produced. It is however important not to confuse this ‘precision’ with accuracy. TAS has not been validated against
real-world projects in the same extensive way as PHPP. Also, a high level of understanding is required for the user
to avoid ‘silly mistakes’ and it could be argued that in this respect PHPP is more robust. One of the key selling
points of TAS is that it is certified by the DCLG for producing Part L2 calculations and EPCs.
In the modelling exercise, the inputs were aligned in the two tools as closely as possible in order to draw a valid
comparison. Weather is one of the most significant variables in the performance of buildings in both simulation
and reality. For the purpose of this exercise data sets, compatible with each piece of software, were derived from
the same source. At each stage, the outputs of the tools were compared, by manipulating the TAS outputs to
match those of PHPP. The annual heating consumption including a heat balance breakdown, and the peak load
were presented for both models. Reasons for any discrepancies were discussed and where possible attributed to
particular technical points in the methodologies.
The issues investigated included:
Single versus multi-zone models. Depending on how a building is zoned, i.e. what activities take place in each
space, and how evenly the solar gains are distributed, each room may perform differently.
Windows including shading device and overshadowing objects. For Passivhaus, fenestration design is crucial to
performance. PHPP uses simple geometric relationships to describe shading, and the shading effect is derived from
dynamic simulations. TAS undertakes 3D shading calculations, and may be more accurate for more extreme
shading geometries. PHPP arguably has a more robust
Internal gains are also very important to the performance of most modern buildings. Both PHPP and TAS have
‘default’ inputs used for certification purposes, but accept alternative inputs for design purposes. In both cases,
care is needed to ensure non-standard inputs are accurate and appropriate to achieve the desired results. Two
approaches were explored; firstly ‘steady state’ internal conditions were generated for TAS (i.e. the same every
hour), equivalent to the internal conditions assumed in PHPP. Secondly, variable conditions (i.e. including diurnal
and weekend variations etc) were applied, but with the same net heat input to the building as for the PHPP
standard conditions.
Ventilation and infiltration. The sensitivity
investigated.
Thermal mass. PHPP accounts for thermal mass with a similar methodology to the shading; it uses a relatively
simple calculation derived empirically from the results of dyna
flows into and out of each building element (in both external and internal directions).
The results for the live project were also presented and results from both packages compared. The project was a
200m2, craft workshop in the south of England, due to begin construction early in 2013, and the design team hope
to achieve Passivhaus certification.
For this building, a comparison will be made of the following results:
• PHPP
• TAS using PHPP equivalent inp
• TAS using dynamic inputs closely reflecting the anticipated use
• TAS using inputs for Regulatory purposes (I.e. NCM inputs for Part L and EPC calculations).
Fundamentally, PHPP and TAS are two quite different tools, each with its distinct limitation
some respects the comparison is therefore purely an academic exercise. It has however, demonstrated that on one
hand, within certain constraints, PHPP produces results comparable with TAS, despite being a much simpler
methodology. On the other hand, TAS is capable, with appropriate skill, of modelling more unusual building
features with greater accuracy. Passivhaus purists may argue that avoiding the necessity for such unusual features
is one of the benefits of the Passivhaus method.
Figure 1: A screenshot from TAS dynamic simulation software showing the craft workshop discussed
standard inputs are accurate and appropriate to achieve the desired results. Two
approaches were explored; firstly ‘steady state’ internal conditions were generated for TAS (i.e. the same every
conditions assumed in PHPP. Secondly, variable conditions (i.e. including diurnal
and weekend variations etc) were applied, but with the same net heat input to the building as for the PHPP
Ventilation and infiltration. The sensitivity of both models to changes in ventilation and infiltration rate were
Thermal mass. PHPP accounts for thermal mass with a similar methodology to the shading; it uses a relatively
simple calculation derived empirically from the results of dynamic simulation. In contrast, TAS calculates the heat
flows into and out of each building element (in both external and internal directions).
The results for the live project were also presented and results from both packages compared. The project was a
, craft workshop in the south of England, due to begin construction early in 2013, and the design team hope
For this building, a comparison will be made of the following results:
TAS using PHPP equivalent inputs
TAS using dynamic inputs closely reflecting the anticipated use
TAS using inputs for Regulatory purposes (I.e. NCM inputs for Part L and EPC calculations).
Fundamentally, PHPP and TAS are two quite different tools, each with its distinct limitation
some respects the comparison is therefore purely an academic exercise. It has however, demonstrated that on one
hand, within certain constraints, PHPP produces results comparable with TAS, despite being a much simpler
e other hand, TAS is capable, with appropriate skill, of modelling more unusual building
features with greater accuracy. Passivhaus purists may argue that avoiding the necessity for such unusual features
is one of the benefits of the Passivhaus method.
Figure 1: A screenshot from TAS dynamic simulation software showing the craft workshop discussed
33
standard inputs are accurate and appropriate to achieve the desired results. Two
approaches were explored; firstly ‘steady state’ internal conditions were generated for TAS (i.e. the same every
conditions assumed in PHPP. Secondly, variable conditions (i.e. including diurnal
and weekend variations etc) were applied, but with the same net heat input to the building as for the PHPP
of both models to changes in ventilation and infiltration rate were
Thermal mass. PHPP accounts for thermal mass with a similar methodology to the shading; it uses a relatively
mic simulation. In contrast, TAS calculates the heat
The results for the live project were also presented and results from both packages compared. The project was a
, craft workshop in the south of England, due to begin construction early in 2013, and the design team hope
TAS using inputs for Regulatory purposes (I.e. NCM inputs for Part L and EPC calculations).
Fundamentally, PHPP and TAS are two quite different tools, each with its distinct limitations and strengths. In
some respects the comparison is therefore purely an academic exercise. It has however, demonstrated that on one
hand, within certain constraints, PHPP produces results comparable with TAS, despite being a much simpler
e other hand, TAS is capable, with appropriate skill, of modelling more unusual building
features with greater accuracy. Passivhaus purists may argue that avoiding the necessity for such unusual features
Figure 1: A screenshot from TAS dynamic simulation software showing the craft workshop discussed
7 t h and 8 t h of November 2012
EMCC, The University of Nottingham – Nottingham, UK
34
PREFABHAUS – MMC AND LOW CARBON HOUSING
Modern methods appropriate for hybrid construction
MICHAEL CRILLY, MARK LEMON
Studio UrbanArea LLP, [email protected]
Institute of Energy and Sustainable Development, De Montfort University, [email protected]
Quality control throughout the entire construction process is critical to the performance of properties seeking to
achieve Passivhaus standard, particularly in regard to air tightness and the avoidance of thermal bridging. In
practice, many errors arise from a misunderstanding of the entire building systems and the integrated nature of
fabric performance with the optimization of services. As buildings get adapted and extended in response to
changing uses and requirements, they also become more complex hybrid structures where standard solutions and
products for typology based retrofitting are not always suitable. When these concerns are combined with the
challenge to mainstream the Passivhaus concept for a diversity of both new and retrofitting projects, quality
control has to be achieved quickly, easily and perhaps most importantly cost effectively.
One possible way of ensuring the appropriate levels of quality and reduction in errors due to on-site management,
damage and control is the use of modern methods of construction (MMC). MMC is more than simply off-site
manufacturing, it is a means to innovate within the design and construction process. As a process, it has the
potential to deliver flexible specialization fabric elements as mass production components and provide possible
responses for new built, retrofitting and hybrid structures in a continuum from new construction ‘products’
suitable for Passivhaus certification through to entire fabric ‘systems’ that can be utilized for one-off elements or
larger new build and retrofitting developments. Where MMC has traditionally been thought of as suitable for
whole and completed structure solutions, the authors suggest that when thinking of properties as evolving hybrid
structures; particularly when you are also being asked to think about adaptation strategies for future climate
change; this begins to significantly blur any distinction between new build and retrofit projects and the use of
MMC elements.
In exploring the use of innovative process using modern methods of construction in the delivery of Passivhaus
retrofit projects in Leicester and Newcastle (figures 1-4) together with proposals for new build CSH6 / Passivhaus
projects in the East of England and the East Midlands, there are common lessons for innovation in the design
process and working collaboratively with the extended supply and fabrication chain, the property owners and
occupants. Using examples from a number of different ‘proof of concept’ projects, we will discuss the potential use
of MMC to produce specific building components, such as modular roof pods, bay window frames and entrance
pods as well as whole frame and structure systems. We will also highlight some of the potential concerns around
professional trust and technical competencies within the construction industry that emerged in working with non-
standard buildings methods and products. These examples will be set within a wider context of process innovation
supported by procedural and management measures, where we have found that the use of modern methods of
construction (both timber and metal frame products) can bring measurable benefits in speed of delivery, reduced
disturbance to occupants and of impact and assurances on quality. These are included with our reflections on the
motivations for housing associations and other large-scale housing developers currently considering responses to
the provision for low carbon housing.
Comparison will be made between the predicted and actual performance of the individual building elements and
the whole house performances from a mix of diagnostic testing, and monitored results. We will provide an analysis
of the performance achieved and cost differences arising form the choice of different off-site MMC systems; for
both proof-of-concept units and larger roll out programmes; compared with traditional build techniques. We will
also review some of the practical issues around successfully linking capital and revenue costs for both
35
development finance and on-going energy costs that could benefit the wider uptake of both MMC products and
Passivhaus standards. This will discuss the concerns around trust and risks in the long-term technical performance
of different MMC systems that result in fewer and less advantageous loan rates that can have the effect of
canceling out the savings due to increased energy efficiency and lower bills.
In discussing the linked concerns around trust, cost, speed and quality, we will provide some current examples of
projects in Corby, Derby, Leicester and Middlesbrough where developments are beginning to consider the issues of
scale and co-design customization of MMC elements and the potential in moving from a ‘proof of concept’ to the
benefits of a ‘flying factory’ approach for Passivhaus and low carbon housing. We will also make the case for
integrated design, working closely with the supply chain, financial institutions and the end-users, as an essential
means of achieving the technical performance required in practice and in a cost effective way that meets the
lifestyle requirements of the occupants.
Figures: (1) Bay Window Pod by Datum being installed at the YHN Greenford Road ‘Retrofit for the Future’ site in Newcastle with (2) completed
semi detached properties. (3) Roof Pod by Envirohomes Ltd being installed at the East Midlands Housing Association terraced property at (4)
Cottesmore Road, Leicester.
7 t h and 8 t h of November 2012
EMCC, The University of Nottingham – Nottingham, UK
36
NEW CONCORDIA WHARF:
ENERPHIT REFURBISHMENT BY PTEA
TOM DOLLARD
Head of Sustainable Design at Pollard Thomas Edwards architects
PTEa was asked to revisit one of their Victorian mill conversion projects from 1984. New Concordia Wharf is a
Grade 2 listed flour mill and warehouse on the south bank of the Thames, and was converted to housing in the
1980s. The present owner of one of the penthouses instructed PTEa to refurbish their flat to the highest
sustainability and quality standards.
The team decided on ENERPHIT as the standard to which the penthouse fabric should be refurbished, and to
supplement this target with various other sustainable design additions such as 6 KWp PV panels, grey water re-
cycling, sustainable building products and natural insulation. PTEa worked with Green Tomato Energy to help
procure this project to Enerphit certification.
Green Tomato Energy used PHPP early on to model the various options available to us. We looked at Passivhaus
as a standard – but the restraints of having to match the existing windows meant this was not viable. The levels of
insulation needed were becoming extreme and we felt that it would not be practical to attain the 15KWH/m2.yr
standard. Although it required space heating, Enerphit provided a more realistic target that could reasonably be
achieved with natural insulation as an option. Certification to Passivhaus standard could also have presented a
problem, as the Passivhaus Institute requires entire buildings to be certified. However the client’s main aim was to
guarantee quality and performance, rather than the certificate itself. So it was decided to go ahead with the
Enerphit target, and that the Passivhaus certification process of commissioning and monitoring would be followed
to ensure quality.
Listed buildings – internal insulation
As this building is listed, the only approach that English Heritage would accept was insulation on the inside face of
the existing construction. The existing appearance could not be significantly altered. The construction is solid
brick walls with steel and timber structure. The penthouse is a 1980s addition of steel and timber clad in zinc that
covers six penthouse flats, and so the only option was to insulate between and under the rafters. With internal
insulation, there is a risk of interstitial condensation, and so we needed to carefully model the movement of
moisture through both the roof and wall. We found that natural, open cell insulations were better at this, and a
vapour-open strategy was preferred.
We examined the differences between natural insulation and phenolic insulation board, and it was agreed to use
natural insulation because of its ability to deal with moisture movement. Wood fibre insulation was preferred
because of its breathability and thermal mass. However, with a λ value=0.38, we needed 240mm thickness of
wood fibre to achieve the 0.11 U value required. Spacetherm aerogel, a vapour-open highly insulating blanket,
was proposed to limit cold bridging round the window reveals and some soffits where head height was an issue.
Certification of Flats?
The Passivhaus Institute advised that you cannot obtain certification for individual flats – yet you can get
certification for terrace houses. There seems to be a double standard here as the external surface area for a top
floor flat is potentially more than a terraced house. Should we be allowing certification of individual flats to the
Passivhaus standard? In this case study there are only two surfaces that are open to the outside climate – the roof
and one external wall. The other walls are party walls and floors with other flats or communal space. Generally,
37
this space is heated, and so there is a provision within PHPP to discount these walls from the calculation.
However, if the neighbour goes on holiday in winter, there will be considerable heat loss through the party wall,
and this should not be disregarded. For comfort reasons, we decided to insulate the party walls and floor. This
results in a highly insulated individual flat which prevents heat flow across party walls. Should we be seeking to
renovate more individual flats to this very high standard, or concentrate on carrying out good practice to whole
buildings?
Figure 1: New Concordia Wharf – Pollard Thomas Edwards Architects 1984 and 2012/3
7 t h and 8 t h of November 2012
EMCC, The University of Nottingham – Nottingham, UK
38
STORIES MEWS
New build dwelling to PassivHaus standard in Camberwell, London
RICHARD DUDZICKI
Director of Richard Dudzicki Associates: Chartered Architectural Practice.
The brief from the clients was to provide a flexible house and artist’s studio which could be used in multiple
configurations. The development is located on the site of a former stable building on a mews to the rear of a
sprawling Georgian house, the client’s current residence. Both the clients are artists and occupy teaching positions
at local institutions. With older children, they felt that the original house had become expensive to maintain and
no longer accommodated their needs. The idea of developing a low energy mews house was suggested and the
brief was further developed throughout the planning and conservation process. The original brief included a
double height artist’s studio within a 2 bedroom mews house. Garage space was provided for a small electric
vehicle or city car and for bicycle storage.
The site is located in an area of historic value, the mews itself is privately owned, unpaved and served houses and
former stables to the rear of properties on adjacent streets. This historical context presented a number of
challenges in terms of achieving the approval of the design and conservation department at Southwark Council
and the Camberwell society. The presiding view was that Stories Mews, had undergone a series of inappropriate
developments. The council expectation, in the case of this project, was for a greater level of sensitivity in the
treatment of the external elements. In response, the design was modified during planning to present an industrial
aesthetic more akin to the former function of the area. Heritage materials were utilised for the exterior whilst a
modern Structural Insulated Panel (SIPs) superstructure from Kingspan was employed to fulfil insulation and
airtightness requirements. Refer to figure 1, indicating proposed street elevation.
Prior to tender the brief was updated to accommodate an additional bedroom, modifying the studio into a single
height space. The clients had decided to remain in their Georgian house on completion of the project and wished
for a greater degree of flexibility to allow renting the new house whilst maintaining access to the studio. This
decision brought its own set of inherent issues. In addition, the requirement to meet PassivHaus Standard was
introduced.
The project was developed to tender stage with particular attention to a number of PassivHaus specific issues. Our
first challenge was achieving the necessary U-values. Using SIPs would provide a solid base for passing the
airtightness requirement, but additional insulation was required to achieve the specific space heating demand.
Kingspan’s initial proposals involved additional external insulation; this proved to be unworkable at the time due to
issues with BBA certification. The decision was made to proceed with internal insulation and to undertake thermal
bridging analysis on a number of difficult junctions to ascertain their performance.
Restrictions on the overall building heights introduced challenges in accommodating ductwork for an MVHR
system. Floor to ceiling heights prevented the inclusion of a separate services void. Instead the ductwork was
located inline with the TGI joists with larger diameter silencers accommodated parallel to the joist runs to reduce
penetration sizes.
The garage was designed as a cold space and insulation was to be applied to the external side of the garage walls
and ceilings. The door between the garage and the internal corridor also presented issues as an affordable, fire
rated, PassivHaus certified unit could not be found. A door set was sourced from an alternative supplier with
modifications to air seals to be made on site to improve performance.
39
The contract was implemented in three stages: The main contractor excavated the site and laid the slab
foundations and below ground block walls. Concurrently the SIPs sub contractor fabricated the superstructure
components. The SIPs subcontractor then delivered the components and assembled the superstructure. The main
contractor then returned to site to complete the fit out and cladding.
Once construction began, a number of additional issues became apparent. Areas of the foundation had to be
modified to fit around existing obstructions. To compensate for lost fabric thickness, higher performance
insulation was installed. The FoamGlas thermal breaks specified to the foundations was omitted in lieu of aircrete
blocks as the product did not possess sufficient strength for the SIPs panel fixings. Detailed engineering design of
the SIPs structure revealed that sections of the two boundary walls of the house would have to be formed in light
timber framing as SIPs could not support the vertical loads in these areas. Internal airtightness membranes were
installed to the timber framed wall and around the floor and roof plates to ensure the airtightness was not be
compromised.
On completion of the SIPs superstructure an air test was commissioned. It was intended that this would provide
early warning of any issues and avoid any disputes between the main contractor and subcontractor. The initial air
test result was 0.59 air changes per hour @ 50 pascals. This was considered to be quite good result given the lack
of experience on the part of the contractors in PassivHaus construction. A later air test, undertaken once the
windows and internal finishes were installed, repeated this result.
The original proposal for satisfying the peak heating load, was to connect a system boiler to a post air heating unit
in the MVHR system. After discussions with the Green Building Store, the decision was made to simplify the system
in view of possible maintenance issues. The installed system consists of a combi boiler feeding two heated towel
rails in the wet rooms and two narrow vertical radiators in the lounge and studio with the MVHR managing
ventilation only.
The overriding issues that lead to challenges experienced during the project planning and construction stages were
clear from the outset: Namely the late stage adoption of the PassivHaus Standard and the appointment of
contractors with no previous PassivHaus experience. The experience has proven the suitability of SIPs for
PassivHaus construction and the adaptability of contractors to meet the PassivHaus stand with proper direction
and some form of performance incentive.
Figure 1: Street elevation of Stories Mews
7 t h and 8 t h of November 2012
EMCC, The University of Nottingham – Nottingham, UK
40
PERFORMANCE EVALUATION FROM
MAYVILLE COMMUNITY CENTRE
MILA DURDEV
bere:architects, Mildmay Centre, Woodville Road, London N16 8NA, tel: +44 (0)20 7241 1064
Introduction
The Mayville Community Centre was built circa 1890 and is located within the Mayville estate in Islington which is
ranked in the top 10% most deprived areas in London. In 2006, bere:architects were asked to refurbish and extend
the rundown building. Through full upgrade of the fabric and systems, as well as onsite energy generation the
building gained Passivhaus certification, thus becoming the first certified non-domestic retrofit in the UK. It also
won multiple awards, including UK Passivhaus Awards 2012, Retrofit category.
Bere:architects together with Roderic Bunn of BSRIA are currently undertaking a deep building performance
evaluation study on the Mayville Community Centre which is funded by the Technology Strategy Board (TSB). This
involves inspection of the performance of the building fabric by thermographic survey, monitoring of energy
consumption, energy generation and internal environmental parameters (temperatures, relative humidity, CO2
concentration).
Although complete annual building performance monitoring data is still not available, preliminary analysis of actual
performance and comparison with design predictions indicates that the building is performing as predicted.
However, optimisation of building performance and thermal comfort is continuing during the occupancy period.
Formal handover to the occupants as well as informal meetings and discussions with them about building control,
thermal comfort and energy use issues, allow for further improvements to be made.
Fabric Performance Data
During the thermographic survey of the building no thermal bridging or air tightness issues were discovered which
confirmed very good thermal performance of building fabric. Airtightness was measured by the blower door test
to be 0.42 ACH-1
@50Pa thus surpassing Passivhaus requirement of 0.6 ACH
-1 @50Pa.
In-use Data
Detailed sub-metering data is available from June 2012, whereas for the 2011/2012 winter period only total
energy consumption is available. Consequently, total energy consumption analysis was carried out for the winter
season, whereas for the summer period more detailed thermal comfort analysis was possible.
Winter season analysis and comparison of the total energy consumption for November - February 2011/12 period
with corresponding PHPP estimates showed that actual consumption for the four months analysed is on average as
much as 16% less than predicted. Further comparison of the same post-retrofit actual total energy consumption
(November – February 2011/12) with corresponding pre-retrofit consumption (November – February 2010/11)
which was based on gas and electricity bills indicated that refurbishment resulted in average total energy
consumption reduction of 91%. However, it needs to be taken into consideration that during 2011/12 winter
season not all the spaces were occupied, but most were heated. Consequently, these should be considered as
preliminary results.
Speaking of summer internal conditions, a comfortable internal environment is intended to be maintained using
external blinds and natural ventilation, especially night purge and cooling of thermal mass.
Thermal comfort analysis conducted for June 2012 indicated that the average overheating percentage (above
250C) for all analysed spaces (office, kitchen, hall, IT suite) is 7.4% which is below the PHPP prediction as well as
41
below the PHPP maximum allowed for certification and could be considered as indicative of good performance.
However, more detailed analysis showed that while in the kitchen and hall there is almost no overheating (0.5%
and 1.9% respectively), higher frequency of temperatures above 250C was noted in some offices and the IT suite
(9.3% and 26.9% respectively). This difference was considered acceptable due to difference in orientation,
occupant density, internal heat gains and space use patterns. Although the percentage is relatively high, average
temperature during the overheating period is not much above 250C (25.4
0C) and maximum is 26.4
0C. On the other
hand, external temperatures during that period were not very high (average 15. 40C) with significant diurnal
fluctuations which should provide significant cooling if night purge ventilation was used. However, minimal
internal temperatures ranged from 19.70C to 21.9
0C indicating that night ventilation was not being used.
In a meeting with the occupants it was confirmed that most were reluctant to employ nigh ventilation due to
security concerns or unawareness of its benefits as well as that blinds were not optimally used in all spaces.
Although all these aspects were explained during the handover, once it was again confirmed that windows and
doors are safe to be left tilted during night and that blinds should be actively used, users of the first floor office
soon reported improvement of thermal comfort.
Relative humidity in all spaces is within 40-60% range 94.8% of the time with average relative humidity ranging
from 48.5% to 53.7% which is optimal in terms of user comfort.
Interior air quality is high (<750ppm) almost 90% of time in the hall and more than 95% of time in the IT suite
(assessed against approximate maximum sedentary CO2 concentrations associated with CEN indoor air quality
standards (BS EN 13779)).
Conclusion
Preliminary results of monitoring data indicated that deep energy reductions through application of strict
Passivhaus standard can be achieved even in the case of retrofitting a rundown exiting building. Although the next
winter season will give a more complete picture, initial results are more than encouraging. Apart from being
indicative of very good building performance, the results also suggest that PHPP provides a robust tool for design
of low energy buildings. Furthermore, the performance evaluation process together with interaction with
occupants proved to be very valuable as it helped establish that the building was not used as it was intended and
thus performance optimisation and additional fine-tuning was possible. This process showed that, although for the
design team some building use and control aspects can be considered as intuitive, the same might not be the case
for the occupants and should thus be given more attention during the handover process in order to ensure optimal
building use.
Figure 1: Mayville Community Centre
7 t h and 8 t h of November 2012
EMCC, The University of Nottingham – Nottingham, UK
42
MONITORING AND DATA FROM PASSIVHAUS SCHOOLS
Soft Landings
LEE FORDHAM, NICK GRANT
Architype Ltd, [email protected]
Elemental Solutions [email protected]
Two Certified Passivhaus primary schools in Wolverhampton have now been occupied for a year. Both buildings
were designed by Architype and built by Thomas Vale Construction within standard budgets as described at last
year’s conference [video of the presentation is available on the Passivhaus Trust website].
This presentation will describe the Soft Landings programme that was undertaken and will highlight key findings
and lessons learnt. Now that teething problems have been sorted, both schools are performing largely as designed
particularly in terms of comfort, air quality and heating demand.
Soft Landings
A Soft Landings programme was developed for the two projects and thought to be essential due to the unique
status of the buildings within the UK. The process included a series of client engagement meetings, which have
been held on a regular basis starting from the building hand over. These meetings were used as opportunities for
the client to raise issues they had with their new building. This process also allowed the design team to learn from
these experiences, thus amending subsequent projects. With the help of an engaged contractor (Thomas Vale) the
issues were then attended to as quickly as possible. Running along side the engagement meetings, presentations
to staff were organised to describe the principles behind Passivhaus and how the building was designed and most
importantly how they should use the building. Simple diagrams indicating how to use the building were also left
with the staff for reference. Pupil consultation was also seen as a fundamental process and as such presentations
and practical engagements were completed, thus allowing the pupils to understand their new surroundings and
making them aware of energy use and consumption. This process is still on going with positive reports from the
clients.
Comfort
Air quality has been found to be good with anecdotal reports of pupils being more alert. Spot readings of CO2
confirm that ventilation is good. It is believed that any reports of ‘stuffyness’ were actually due to higher
temperatures rather than insufficient ventilation as discussed below.
Early reports of overheating caused the design team some alarm given the light weight nature of the timber frame
structures. This turned out to be due to a combination of control problems with the night ventilation and higher
than required boiler flow temperatures. It soon became clear that many conventional assumptions about BMS
operation are not appropriate for a Passivhaus building. For example the buildings experienced overheating in
early spring. Unfortunately the BMS was preventing the secure night vents from opening because the outside air
temperature was below a minimum set point so that the heat built up over a number of days. Changing the set
point allowed the windows to open and temperatures dropped. The soft landings process has led to significant
changes in window and ventilation design for the next project.
Another problem resulted from the use of a conventional weather compensation algorithm that raises the boiler
flow temperature as the outside air temperature drops. However a Passivhaus building has a very long time
constant and makes good use of the high solar radiation that is typical of very cold weather with clear skies. The
43
problem was compounded by the fact that the installed boiler capacity was 130kW with a minimum output of
24kW compared to a design peak load of 26kW for a 2,200m2 building (figures from Oakmeadow).
Kitchen overheating was a key concern at the design stage but was addressed by radically reducing gains rather
than boosting ventilation rates. This has been extremely successful and the cooks are very happy with the
induction hob that was key to this approach. The only day of overheating was when the frost coil came on due to
low outside air temperatures. This was another unforeseen control issue and it is hoped that heating coils can be
designed out of future projects as we do not believe they are required.
Energy
Early indications suggest that energy consumption for space heating is comfortably under the 15kWh/(m2.a) design
target and should come down even lower now that the weather compensation algorithm has been changed
(windows were being opened to dump heat). Hot water use for Oakmeadow is around 12kWh/(m2.a) with about
60-65% losses despite considerable efforts to minimise the distribution pipe length and heat loss. The next school
will use carefully placed local electric water heaters and no pumped circulation.
Energy use for lighting is higher than expected at around 15kWh/(m2.a) for oakmeadow and 14kWh/(m
2.a) for
Bushbury. Again automatic controls seem to be the likely culprit and we suspect that simple switches might well
deliver energy savings.
Primary energy use for both schools is around 175kWh/(m2.a) against the Passivhaus upper limit of
120kWh/(m2.a). A significant 35kWh/(m
2.a) primary energy is due to frost protection in the sprinkler pump room
which is un-insulated and must not drop below 10°C, a serious oversight by all including Building Regulations.
One year’s data will be available for the conference presentation but was not ready in time for this abstract.
Main Lessons
Interestingly most of the design changes that have been informed by the soft landings process should result in
simplifications and cost reductions for future next projects. It is clear that the soft landings process is invaluable
and needs to be factored into budgets. However it does rely on a having an engaged main contractor being
proactive throughout the entire process.
Figure 1: Winter sun at Bushbury
7 t h and 8 t h of November 2012
EMCC, The University of Nottingham – Nottingham, UK
44
KNIGHTS PLACE
Case study report on the monitoring and occupation of a
large scale residential Passivhaus in the South West
DAVID GALE, TOMAS GÄRTNER
Gale & Snowden Architects and Mechanical Engineers
[email protected], [email protected]
This contribution is a case study report on the design, delivery and in-use monitoring of Knights Place and Rowan
House, three blocks of Passivhaus flats in Exeter, Devon UK.
When the client, Exeter City Council, was offered a funding opportunity by the HCA to develop the first council
housing in Exeter since 20 years, it was decided to use this chance to provide exemplary, quality affordable
housing, built to the highest standard of energy efficient construction with the aim to successfully target fuel
poverty and combat climate change at the same time.
In 2008, Gale & Snowden Architects, Mechanical Engineers and Landscape Architects were commissioned to
develop designs for 12 brownfield sites throughout Exeter. A series of workshops were held with project
stakeholders and the design team to review construction alternatives. From these workshops it was decided to
adopt the Passivhaus Standard. ‘Knights Place’ and its sister scheme ‘Rowan House’ were the first of these sites to
be built and together comprise of 21 flats in three buildings. Knights Place was completed in June 2011 and has
been occupied for more than a year. Rowan House was completed in 2010 and has since been occupied.
The detailing and material specification follows Building Biology best practice guidance to improve the health of
the tenants. This includes the use of ceramic floor tiles to reduce dust mite infestation, minimal VOCs, PVC free,
best practice daylight level and an electrical design that reduces electro and magnetic radiation.
The Landscape was designed to meet key human needs of food, water, energy and shelter in a way that also
enhances the natural environment by employing Permaculture design principles. It integrates the new
development with its surroundings and creates a sense of ownership with its residents. By understanding how
biological systems work in nature and applying them to human settlement design, these principles harness
productive and biodiversity-rich environments that are low-maintenance and self-perpetuating.
Benefits of ecological landscaping include:
� Lower energy inputs by reducing chemical and mechanical interventions
� Lower maintenance requirements and reduced running costs due to this reduction of inputs
� Lower water consumption
� Reduce wind chill factors onto buildings and moderate the microclimate
� Educational – linking user input and output and providing a connection for people with the natural
environment creating a sense of ownership
� Reduce transportation pollution by using bio-regional resources
� Enhance the ecology of a site
Further key achievements include:
� Code 4 of the CSH
� Lifetime Homes Standards compliant
� Private Permaculture gardens for all residents
� Solar Panels will further reduce the energy demand for domestic hot water
� Best practice daylight levels throughout
45
� 100% energy efficient light fittings throughout
� Secured by Design compliant
� Independently assessed under the Building for Life standard with a final score of 18.5 out of 20
� Low water strategy to reduce water demand to 80 litres/person/day
The project received funding under the TSB Building Monitoring Programme. The main objective is to monitor the
environmental and energy performance of 3 typical flats at Knights Place and 3 flats at Rowan House and compare
their performance in use against the design intent. The project is carried out over 24 months covering 2 winters
and 2 summer periods, and investigates the following elements:
� Review of SAP calculations and PHPP calculations.
� Review of the services installations and commissioning data in each of the 3 flats
� Main meter reading of electricity and water consumption through smarts meters and sub metering of main
supplies to monitor electrical consumption associated with heating, lighting, cooking, ventilation,
appliances etc.
� One of the solar panel systems will be monitored in one of the 3 flats. Flow and return temperatures and
energy will be monitored.
� Air flows for the MVHR systems are retested against commissioned air flows. Temperature and humidity
monitoring will consist of a sensor in all 4 ducts of the MVHR system in each flat. Temperature and
humidity monitoring via the sensors shall be over 2 winters and one summer period.
� Space comfort monitoring in 2 main rooms in each flat. This involves monitoring temperature, humidity
and C02 levels in 2 main rooms of each of the flats over 2 winter periods and during one summer period.
� External temperature and climatic monitoring via weather station. This involves installing an onsite
weather station to record external climatic conditions such as temperature, humidity, wind speed, rainfall,
solar irradiance.
� Initial preliminary occupant survey to all 18 flats – to be narrowed down to 3 flats which will receive
standardised questionnaire
� Interviews and walkthroughs with occupants. This will also include qualitative semi-structured interviews
with occupants and will help determine controls issues, lifestyle etc
� 2 post construction air permeability test for all 3 flats
� In-situ Uvalue monitoring via dynamic flux method
The monitoring results so far show that the buildings use a fraction of the energy of traditionally constructed new
buildings and that on average the design intent was met. In all the monitored flats an optimum air quality was
maintained and the occupants successfully managed internal summer comfort throughout the first year simply via
natural ventilation.
Figure 1: Knights Place Exeter, completed June 201
7 t h and 8 t h of November 2012
EMCC, The University of Nottingham – Nottingham, UK
46
ADAPT TO CHANGE
The use of probabilistic weather data in the PHPP to develop a climate change adaptation
strategy for a residential extra care facility
TOMAS GÄRTNER
Gale & Snowden Architects and Mechanical Engineers,
The climate is changing. Considering the life expectancy of our buildings this will particularly impact on the
construction industry. The majority of buildings constructed today will still be in use in the second half of this
century. Although there is a growing consensus amongst scientists that the climate will change, we still design and
optimise our buildings based on past experience.
Current climate trends already show, we will need to adapt our built environment, to deal with a climate that will
be significantly different from that in which it evolved. During the heat wave in 2003 in France, there were 14,802
heat-related deaths mostly among the elderly (French National Institute of Health). Most people did not know how
to react to very high temperatures and most residential facilities built in the last 50 years were not equipped to
perform under these conditions. Projections prepared by the Oxford Institute for Sustainable Development
(Oxford Brookes University) show that most homes in the UK will suffer from overheating in summer beyond 2050
and some from 2030.
This contribution investigates the potential impacts of climate change on the design and performance of a
residential extra care facility in Exeter (Devon, UK), to be built to Passivhaus Standard, using future probabilistic
weather data in the PHPP with the aim to develop a climate change adaptation strategy. Residents are likely to be
frail and the building design had to ensure the building's internal conditions remain comfortable and stable for this
more vulnerable user group.
The project received government funding under the TSB 'Design for Future Climate' programme in 2010.
Construction is scheduled to start in 2012 and to be completed in 2013.
Method
The IPCC's fourth assessment report shows significant warming over land for different socio-economic projections
of CO2 emissions. UKCP09, the latest climate projections based upon these emissions scenarios incorporate
climate models from the Met Office and others. The projections are probabilistic in nature instead of deterministic
so as to allow users to assess the level of risk. Using this data Exeter University’s Prometheus Project developed a
methodology for the creation of probabilistic future reference years compatible with common building simulation
software and a methodology for estimating wind direction and speed. For this project these files were converted
with help from the PHI for use in the PHPP.
The project team visited Passivhaus care facilities in Germany that were built between 2000 and 2010 and
interviewed designers, care providers and residents.
A qualitative risk assessment was carried out to analyse the tolerance and exposure to climate change related
risks, for both the building and the end users, followed by a quantitative analysis. Various shading, ventilation,
landscaping and construction methods were modelled in PHPP and IES dynamic modelling using current and future
weather data for the years 2030, 2050 and 2080 to develop an adaptation strategy. The various options were
costed and a life-cycle-cost analysis was prepared to support the client in the decision making process.
47
Discussion and conclusions
Under future UK weather scenarios, rising average temperatures and increased solar radiation caused by a
reduction in cloud cover will increase the risk of overheating. Already there has been an increase in the average
number of Cooling Degree Days (CDD) in all administrative regions of the UK as a whole, between 1961 and 2006.
At the same time the average number of Heating Degree Days (HDD) in the UK has decreased between 1961 and
2006, and future UK weather scenarios indicate a further 30% decreased number of Heating Degree Days by 2080.
These results are consistent with research carried out by the CIBSE.
It could be argued that in the future super insulation and low energy design principles will be less important with
the future UK climate becoming milder. However, according to data from the International Energy Agency fuel
prices are expected to increase by 50% by 2050 (IEA 2009). Thus, even under future scenarios net heating costs
are likely to increase making the principles behind the Passivhaus concept as economically viable as they are
today.
Furthermore, the modelling results from this project indicate that the same low energy design principles that help
to reduce heat losses have proven to be equally successful to future proof a building against the risks of climate
change and to reduce the frequency of overheating in summer as long as a successful ventilation strategy can be
implemented. However, climate change requires a fundamental change in the way we think about design;
changing from approaches that are based on past experience to those that are based on calculated projections of
future climate. Some strategies more typical for Passivhaus buildings in Southern European climates could
become applicable for the UK under future UK weather scenarios,
A life cycle cost analysis, carried out for this project, showed that if these strategies are implemented subsequently
together with the regular maintenance cycles the building can be future proofed against climate change at little
extra costs with the economic benefit of extending the useful life of the building.
Climate change adaptation is becoming a greater concern for clients. To ensure comfort and commercial viability
designers need to assess the potential impacts from climate change from the outset. Practices with the skills to
carry out climate change risk analyses, to develop solutions and to make adaptation recommendations have a key
business opportunity. To enable designers to carry out climate change risk analyses, probabilistic climate data
needs to be developed for the PHPP.
Figure 1: Visualisation of ‘Exeter Extra Care’ Project
7 t h and 8 t h of November 2012
EMCC, The University of Nottingham – Nottingham, UK
48
MAINSTREAMING PASSIVHAUS HOUSING DEVELOPMENT IN THE UK
JONATHAN HINES, LARS CARLSSON
ArchiHaus Ltd 01981 542111 [email protected]
Introduction
ArchiHaus is a new company that has been formed, in partnership with architects, Architype, specifically to bring
Passivhaus housing development into the UK mainstream at a competitive and affordable price – ie at no extra
cost.
The key objective of the project is to bring the development of Passivhaus into the mainstream of housing
development at a significant scale, and at a competitive and affordable cost. This will be achieved by rethinking the
build process - specifically by optimising the design and construction of passivhaus housing from first principles as
an innovative 'product' suitable for efficient manufacture in an offsite factory facility.
Our first project, for an initial scheme costing £20million for 150 Passivhaus houses located in Herefordshire, is
currently in the planning stage.
Other sites are being developed for future roll out to sustain an ongoing programme, and we anticipate also
supplying houses to other developers and architects. Our aim is to radically transform standards of construction in
the UK.
The challenge
Frustration with the reluctance of housing developers to embrace Passivhaus in anything other than pilot projects,
led us to develop a new strategy for delivering 100% Passivhaus housing at a price that is competitive with those
mainstream developers, and an ambitious vision to transform the UK housing market.
We are rethinking the design of ‘a house’ as an optimised ‘passivhaus house’ from first principles, to enable it to be
prefabricated in a new ‘house factory’ in order to achieve an efficiency of production that delivers passivhaus at
the same or less cost that standard housing development, and instead of Code.
The vision – affordable Passivhaus
Whereas most housing developers build to minimum standards of quality and sustainability, our vision is to
achieve Passivhaus as our minimum standard, but constructed at the same price as a developer. Whereas some
house developers will build to higher standards in one-off pilot projects, our vision is to make Passivhaus the
affordable mainstream norm, that is, simply achieved as standard.
This vision could not be achieved by tweaking or adding to the way houses are currently built. Instead this project
is to completely rethink the design and build process. We are redesigning 'the house' from first principles, in order
to optimise construction to achieve Passivhaus through 100% prefabrication.
Specifically we have used PHPP as a design tool and driver, to optimise the form, shape, layout, fabric, window size
and arrangement, of the houses, in order to maximise energy performance, simplify processes for factory
prefabrication, and minimise construction cost.
Alongside this Passivahus optimisation of the house design, we have undertaken a study of traditional vernacular
forms and found fascinating synergies which have influenced the design development of our houses
Houses will be manufactured in a ‘house factory’, which are common in Sweden and Germany, and realise
impressive cost reductions whilst achieving higher quality. To date however most factories have seen passivhaus as
an extra complication and cost, and we aim to challenge that.
49
Our site layout has taken a radical approach, quite different to that of a typical developer scheme, in order to
optimise Passivhaus performance. Houses are all orientated within 15 degrees of south and spaced 21 metres
apart to maximise winter solar gain, with all principle rooms located to the south side of the plan. An innovative
landscape creates a rural rather than suburban feel, with swales and hedgerows creating privacy to houses with
their south elevations facing public spaces.
Our wider aims include:
• developing integrated partnerships with multiple suppliers from the earliest design stage through
construction to achieve lower costs and reduced defects
• utlising fully integrated cross discipline BIM for design and production optimisation
• creating healthy internal environments by using natural materials and finishes in conjuction with MVHR
for good air quality
The vision – living communities
Our initial projects are located within rural communities, where there is not only great housing need, but also
serious economic and environmental challenges.
Many rural communities have lost many of the facilities that they value, and are struggling to maintain the viability
of those facilities that are remaining. Too often the shop or post office has suffered from a lack of business and
closed down, the pub is struggling to stay open, the village school is under threat of closure due to lack of local
children, and it is unsafe to walk along lanes where the car dominates.
Our wider vision is to support and sustain ‘living’ villages:
• with sufficient population to sustain basic and convenient services including shops, pub, church, village
hall, school and bus services
• with facilities to support every age group -- young children, teenagers, families and older people –
including health and education services
• a place where people can walk or cycle around safely to get to those facilities
• with local employment opportunities
• with enough space for people to grow food individually in decent size gardens, or together in allotments
or community orchards
• has houses that people can afford to buy or rent, that are designed and developed to suit their needs
We have developed an innovative architectural approach that is a contemporary re-interpretation of the
traditional rural vernacular, set within a dynamic sustainable landscape with food growing, community orchards,
wetlands and natural play. We are also currently applying the thinking we have developed, to the design of urban
sites to create a more sustainable vision for urban, as well as rural housing.
Next steps
The planning application for our first scheme of 150 houses is due to be submitted in October 2012, and
construction is anticipated to be commenced in 2013.
Figure 1: Site plan Figure 2: Elevational stud
7 t h and 8 t h of November 2012
EMCC, The University of Nottingham – Nottingham, UK
50
NOTTINGHAM H.O.U.S.E.:
THE CHALLENGES OF A PORTABLE PASSIVHAUS
An experiment in modular passivhaus construction for
mass-market contemporary sustainable housing
BEN HOPKINS
ben.hopkins53@gmail.
In the summer of 2009 a team of students from the University of Nottingham’s Department of the Built
Environment arrived in Madrid and in 7 days assembled a functioning two bed house designed to meet both
passivhaus and code for sustainable homes level 6. There, it formed part of the Solar Decathlon Europe 2010
competition, an international zero-energy housing competition started by the US government, during which it took
second prize for sustainability as well as demonstrating to the thousands of visitors the benefits of simple passive
design. The project had been designed a year earlier by a group of DipArch students and was then constructed by
2nd and 3rd year undergraduate students as a live project with the help of lecturers, local architects and
consultants.
Apart from the student design and build team, there were a number of factors that made the Nottingham HOUSE
unusual. To begin with, the competition (and the HOUSE’s exhibition at Ecobuild 2010) meant that construction
on site was limited to a few days. The HOUSE also had to be designed to function passively in both northern and
southern Europe. The student design team also added to the already large brief that it should be a mass-market
strategy, aiming to show an affordable, low-energy housing prototype to housing in the UK.
As a result of these criteria, a decision was made early on to construct the house off –site, to allow for cheaper and
more precise construction, and critically to allow for a streamlined site-based assembly. However, the nature of a
passivhaus is very much contrary to a house with so many joints; as such the design team set to thinking how one
makes a portable passivhaus.
To make the house demountable, the team designed it in eight modules, dimensioned to standard haulage
dimensions. These modules could be fully fitted out, with only the connections for services, airtightness, internal
finishes and cladding to be applied on site. To achieve this idea the house was constructed from a base of pre-
fabricated glulam frames in-filled with timber I studs, which are then made into cassettes after being filled with
isover insulation and covered in high density plasterboard for both rigidity and thermal mass. Once ready, the
panels were then assembled into their respective modules, which were fitted and clad within the factory. The plan
was that, on site, each module’s vario airtightness membrane is would lap together at the module joints on the
external face, though in reality this junction was particularly difficult to maintain after numerous disassembles.
The majority of the lessons learned during the process relate to these junctions; due the performance specification
of the project, and the realities of dry construction, it was imperative that each part of the HOUSE fitted its
neighbour perfectly, yet there were a number of junctions that required remedial work due to dimensional issues.
To avoid these issues the project would have been better served considering processes closer to those seen in car
manufacture, or even smaller scale product design, where construction is tested virtually or via smaller scale
protoypes. Due to time and financial constraints the HOUSE had to become its own 1:1 prototype, with the
modular construction allowing training for students, and testing of ideas on less critical modules. This allowed
many issues to be resolved during the construction without losing build time, however, it did not allow for pre-
planning of project wide issues such as connections, and so it is clear that for any future project hoping to achieve
the performance of the HOUSE a much longer lead in time should be given, to allow for much greater integration
of systems, and to allow thorough BIM testing. It was considered that in future applications of a similar housing
51
type the system of construction could also be reconsidered, to allow for a simpler, even more prefabricated
strategy which could incorporate the airtightness performance into the envelope without the need for a
membrane, which was by far the most trying feature of making a passivhaus that can be disassembled.
One of the greatest surprises of the competition was just how well the HOUSE performed compared to the many
houses with significantly more funding and more high-tech services. Though systems issues meant that critical
BMS systems were unavailable and therefore many of the 24 hour internal comfort targets were missed, the house
performed far better than the majority of competitors, and without the need for mechanical systems during the
day. Many of the more high tech entrants who had taken a more traditional passivhaus strategy failed to cope
with the internal loads of visitors and the heat of summer-time Madrid, and required large amounts of renewables
to offset the power consumption of their systems. The Nottingham HOUSE, however, managed to maintain
comfortable temperatures throughout, without using power and therefore allowing the use of more realistic
priced lower yield PVs.
It is interesting to note that many of the visitors stated that they were far happier with the traditional window
based ventilation system in use which was seen to be much simpler, as well as the other non-standard features of
the HOUSE which were critical to its success, such as the L shape plan and the double height void, both of which
were contrary to passivhaus practice, but allow for the house to function in a terrace configuration, and to provide
spaces that improve on typical housing types. As such the HOUSE suggests that while passivhaus design is
incredibly useful in providing low-energy solutions for contemporary mass-market housing, it must be a part of the
design strategy and not the key driver.
Figure 1: A module being tested by students within the assembly hall
7 t h and 8 t h of November 2012
EMCC, The University of Nottingham – Nottingham, UK
52
WIMBISH PASSIVHAUS BUILDING PERFORMANCE EVALUATION
Twelve months of monitoring
MARTIN INGHAM
Associate, Centre for the Built Environment, Adapt Low Carbon Group, University of East Anglia
The Wimbish Passivhaus development derives from Hastoe Housing Association’s record of accomplishment in
sustainable housing, and their desire to tackle rural fuel poverty. Hastoe intend that Wimbish be the first of many
Passivhaus developments, and were keen to confirm that the buildings are performing as anticipated. A bid to the
Technology Strategy Board for an in-use performance and post-occupancy evaluation study was successfully made
with UEA assistance.
The evaluation is to study whether, in practice, the buildings meet the occupants’ needs, Hastoe expectations, and
the Passivhaus design criteria. A rural exception scheme, with a mix of social and shared-ownership housing, the
development has been designed to be cost-effective and replicable. As an approach that could be suitable for
mass-market it is important that it be studied carefully to maximise learning.
The award-winning development consists of 8 houses (two and three bedroom – 76 and 88m2) and 6 one bed
(51m2) flats [see Figure 1]. The design was by Parsons+Whittley, and construction by Bramall Construction (now
Keepmoat). The structure is essentially lightweight block-work with external insulation and render. The dwellings
are triple-glazed, oriented east-west to enable larger south-facing windows to the main living accommodation,
with solar control by brise-soleil, large overhangs and external blinds. A solar thermal system works with a small
boiler to meet hot water needs, and to meet the minimal supplementary space heating demand, which is delivered
through the ventilation system.
This two year domestic new-build study, which started with handover end-June 2011, is looking at both the
performance of the fabric and from the perspective of the occupants. The occupants are looking for low bills, and a
comfortable environment; analysis of the first year of data indicates that the building scores highly on both fronts.
The design and construction processes, including commissioning, were observed and are being reviewed for
reporting to the Technology Strategy Board. All 14 units have been monitored for gas, electricity and water
consumption, with electric sub-metering, and for temperature/humidity in their living rooms. Three units are
monitored more extensively: temperature and humidity in multiple locations, carbon dioxide levels in living and
bedroom space; along with the performance of the vital MVHR system. A University of East Anglia PhD Researcher
has investigated occupant practices; in particular, how they influence energy consumption, and how they may be
modified to reduce consumption.
Living in a Passivhaus home to maximum advantage requires subtly different skills to those required in a more
conventional house; for example how to benefit from solar gain without overheating; when to use the MVHR and
when to open the windows; what to do if they feel a little hot, or a little cold. Guidance was provided for the
occupants in a Tenant Handbook, and through pre-, during and post-handover support. The effectiveness of this
guidance and support has been reviewed.
The project has been supported by the EU Build with CaRe project, where UEA was a partner. Performance during
the first winter has been analysed and reported as an interim report on www.buildwithcare.eu. The presentation
to the Passivhaus Trust Conference will also report on the first full summer of occupation, along with twelve
months of energy and comfort data.
53
Gas consumption for space and water heating aligns with Passivhaus (and PHPP) design expectations. Electricity
use is a little higher than desirable for a Passivhaus, being closer to UK averages; the appliance audit is expected to
confirm that old appliances, brought with them by the occupants, are a major factor in raising electricity use. The
Building Use Studies survey conducted for TSB recorded high levels of occupant satisfaction; this is confirmed by
the monitoring data and by interviews with the tenants. Most households chose to maintain quite high
temperatures through the winter, and were delighted that they were able to achieve this with such low utility bills
(which would have been even lower if energy companies did not penalise low usage). Continuing these behaviours
into summer has led to temperature readings in some houses that would class as over-heating, yet it seems as
though this may partly be by choice.
Valuable lessons have been learned from the build process, and from the design, installation, commissioning and
operation of the systems, especially the MVHR. Transferring knowledge to the occupants so that they can get the
best out of the houses to suit their needs has not been easy, and feedback to them from the performance
evaluation is planned to overcome any concerns they may have and hopefully improve performance even more.
Overall, findings to date are that the occupants are very happy with their homes. This makes Hastoe and the
designers happy too!
Figure 1: Wimbish Passivhaus Flats
7 t h and 8 t h of November 2012
EMCC, The University of Nottingham – Nottingham, UK
54
SCALING UP:
UNIVERSITY OF LEICESTER NEW MEDICAL BUILDING
SIMON JESSON
Associated Architects, [email protected] 0121 2336600
There is, perhaps, a perception that the applications of Passivhaus standards in the UK to date have been
restricted to relatively small scale, often bespoke projects, such as residential buildings, schools and modest
commercial office schemes.
The team were keen to explore whether Passivhaus could be applied to larger scale projects, as are more
commonplace in Europe, and to identify the challenges in the shift in scale?
The University of Leicester set itself the target of reducing its estate’s CO2 emissions by 60% by 2020 and this will
inevitably shape the design of new buildings. Associated Architects were commissioned to design a new medical
Teaching Building, which accommodates 13,000sq.m of teaching space, academic offices and research facilities on
a city centre site. The University and Design Team have chosen to design the building to meet the Passivhaus
standard, in order to achieve the EPC A target set by the University’s brief.
The scheme is currently in the detail design stage but already the challenges of up scaling are apparent.
Passivhaus requires that consideration of building orientation is essential and extensive and explanative
consultation has had to be held with the planning authority so they could fully understand how proposed building
massing and orientation had a significant impact on the environmental viability of the project, especially in the
context of sensitive townscape context. Urban sites, with their inherent constraints of finite site size, background
noise, air quality and overshadowing from neighbouring buildings present technical challenges to design
development. The potential sole reliance on mechanical ventilation and cooling systems within sealed buildings
runs against the Passivhaus objective of energy reduction.
In scaling up, Passivhaus buildings have larger gross floor areas to accommodate the larger plant rooms and risers
to accommodate the type of mechanical plant required. This ‘inefficiency’ not only incurs additional capital costs
in addition to the provision of Passivhaus certified materials and systems, but can also conflict with site constraints
in terms of permitted buildings heights. Rooftop plant rooms being larger and displacing plant into or under the
building, compounds the ‘extra over’ capital cost issue further. The technical requirements for achieving the
Passivhaus standard building must be economically achievable. The balance between capital cost versus life cycle
costs and long term cost savings needed to be carefully considered and analysed.
Working for a financially accountable organisation such as the University, required that the Design Team’s
component specification and procurement strategy, allow the demonstration of competitive purchasing. We were
encountering challenges in sourcing commercially available and insurable Passivhaus certified components and
construction techniques that are suitable for large scale projects with a contemporary aesthetic. The number of
certified aluminium curtain-walling systems for example available in the UK is pretty much limited to Schuco. This
could be said to be a monopoly.
Large scale Passivhaus buildings are complex to operate and manage, and will require suitably trained FM teams to
ensure they are managed to realise the energy savings. Without this, the buildings will be expensive ‘white
elephants’. For the University, there was also the challenge of communicating the benefits and constraints of a
Passivhaus building to 400 staff and 2000 students, who will have a limited understanding of construction and all
of whom have a part to play in the long term success of the project by reducing their primary energy demands.
55
We are finding that there is a very real lack of Passivhaus knowledge and experience in delivering the standard
amongst Main Contractors and their sub-contractors. The use of the Passivhaus ‘brand’ and terminology has the
ability to convey the low energy nature of the development, but contradictorily can increase the cost expectations,
due to incorrect perceptions and the commercial imperative. The scheme is currently in its pretender
procurement, and is due to complete in July 2015.
Figure 1: The New Medical Building for the University of Leicester, completion due 2015
7 t h and 8 t h of November 2012
EMCC, The University of Nottingham – Nottingham, UK
56
CURRENT AND FUTURE ENVIRONMENTAL PERFORMANCE OF A VICTORIAN
TERRACED HOUSE REFURBISHED TO PASSIVHAUS STANDARDS
HANIYEH MOHAMMADPOURKARBASI, STEVE SHARPLES
School Of Architecture, University Of Liverpool, Abercromby Square, Liverpool L69 7zn, Uk
[email protected] [email protected]
Reducing energy demand in the existing residential building stock has been identified as a core aim of UK and EU
energy policies to mitigate climate change and global warming trends. To achieve this aim a variety of different
building codes, regulations and standards have been developed. Among them, the Passivhaus certification
imposes the strictest criteria regarding heating demand. The vast majority of Passivhaus dwellings built to date
have been new constructions. Given that 70% of all current homes in the UK will still be present in 2050 it is crucial
to analyse the potential application of Passivhaus standards to the retrofitting of existing dwellings. Although, for
older buildings, it is often difficult to achieve the Passivhaus standard, the use of Passivhaus technology for each
building component in such buildings can make a significant improvement regarding comfort, energy requirements
and CO2 emissions. The EnerPHit Standard has recently been developed as a good practice refurbishment guide for
Passivhaus renovations. It has set a slightly different standard requirement to the full Passivhaus standard for new
build, and an old building can receive a "EnerPHit – Quality-Approved Modernisation with Passive House
Components" certificate.
This paper examines the possibility of reaching EnerPHit standards for a 19th century Victorian end terrace house
in Liverpool, UK. The terrace was refurbished by the Plus Dane Group as part of the Retrofit for the Future
programme with the aim of getting as close as possible to new-build Passivhaus standards on a 130-year old home.
Since a retrofit Passivhaus standard was not in place at the time of starting the project the PHPP (Passivhaus
Planning Package) program was used to certify the house based on new build Passivhaus standards. The house did
achieve the standards for most aspects, with the main exception being the air tightness level achieved in the
refurbished terrace.
For the purpose of this research the thermal software DesignBuilder was used to simulate the terrace’s energy
performance after refurbishment for different climate scenarios. Like PHPP, DesignBuilder includes energy
calculations (R or U-values), sizing of the heating and domestic hot water (DHW) systems, calculations of auxiliary
electricity and primary energy requirements. However, DesignBuilder is far more accurate as it can be detailed
down to individual room/zone levels for different temperatures while PHPP uses an Excel spreadsheet that
operates at a whole building level using monthly average temperatures. With PHPP it is possible to obtain a
building certificate but there is no guarantee that this PHPP certified building will have acceptable thermal comfort
levels in each zone of the building. The calculation procedure for estimating the energy impact of air-tightness is
the same for both DesignBuilder and PHPP. However, DesignBuilder, in natural ventilation mode, can allow for the
effects from changes in wind speed on the building instead of one continuous infiltration rate, as in PHPP.
Simulation results indicate that Passivhaus standards are achievable in a refurbished Victorian terrace for current
weather data in Liverpool regarding primary energy demand, CO2 reductions and summertime comfort. Although
the house’s heating demand went above the standards the criteria for individual building components were met. A
high level of air tightness (2.75m3/hr/m
2) was achieved after refurbishment.
Predicted DesignBuilder results were then validated against measured data taken from an extensive long term
monitoring programme in the terraced dwelling carried out by the Plus Dane Group. Having validated the program
made it possible to investigate how the same refurbished terraced house might perform in the warmer climate of
London for both current and future climate scenarios. Heating demand for London will meet EnerPHit criteria.
Figure 1 compares heating demand for the house with and without refurbishment for different climate scenarios.
57
However, summer overheating and higher cooling energy demands are very likely to occur in this terrace house in
London for both current and future weather in the second half of this century. Although the house meets the
cooling demand and summertime comfort criteria for current weather data, it will surpass these benchmarks
during its life based on predicted 2050 and 2080 London weather data. Simulation results indicate that the
summer discomfort hours (over 25°C) and cooling demand will be more than double their current levels by 2080.
To deal with this overheating user-controlled shading has been suggested as the most effective adaptation
measure for reducing annual overheating hours in the future climate of England. It can minimize overheating hours
whilst, in the winter, maximising solar gain to reduce space heating energy use. However, in some cases, especially
by the 2080s, the external temperature will be too high at times to be brought below the ‘comfort’ level passively.
In this case providing active cooling without surpassing the Passivhaus energy demand levels is a challenging task.
In conclusion, comparison of results for heating demand suggests very little decline in heating demand in the
future for the house with no refurbishment, while the PassivHaus refurbishment shows a sharp reduction in
energy demands and CO2 emissions even after active cooling measures are integrated into the home.
Figure 1: Comparison of space heat demand for the terraced house located in Liverpool and in London for different climate scenarios.
0
20
40
60
80
100
120
140
160
180
pre-refurb London
pre-refurb Liverpool
refurbished London
refurbished Liverpool
EnerPHit PassivHaus
kwh/m2.yr
Space Heat Demand
current
2020
2050
2080
7 t h and 8 t h of November 2012
EMCC, The University of Nottingham – Nottingham, UK
58
PERFORMANCE EVALUATION OF CAMDEN PASSIVHAUS
Performance exceeds design targets!
SARAH LEWIS
bere:architects, Mildmay Centre, Woodville Road, London N16 8NA, tel: +44 (0)20 7241 1064
Introduction
Situated in the London Borough of Camden, the Camden Passivhaus achieves the UK’s 2016 zero carbon
compliance standard. It was bere:architects’ first certified passivhaus, and also London’s first passivhaus.
Bere:architects used this project as a vehicle to learn about advanced, thermally-efficient European timber frame
techniques; by means of an 18 month knowledge transfer exercise, with Matthias Kaufmann of Kaufmann
Zimmerei who joined the office in 2008. The Camden Passivhaus acted as a ‘test-bed’ for bere:architects’ Welsh-
made passivhaus social housing prototypes.
Detailed monitoring of the Camden Passivhaus by University College London, has found that passivhaus techniques
have resulted in a comfortable and healthy home for the client’s young family, and is showing that the building is
performing even better than designed. The Arup BUS occupant survey found it to have the highest user approval
rating of any low energy house officially tested using the BUS methodology. This is all the more remarkable when
one considers that the occupant did not commission the house and does not have any real interest in the
passivhaus standard other than the comfort she enjoys and the health benefits she has experienced.
The fabric and in-use performance of the Camden Passivhaus has been independently monitored in collaboration
with University College London and funded by the UK Government’s Technology Strategy Board.
Fabric Performance Data
The fabric performance of the house has been analysed with blower door air pressure tests, co-heating tests,
tracer gas tests, in-situ U-value heat flux measurements, infra-red thermography, thermal bridge analysis and a
forensic review of all of the building systems over the course of 2011.
The blower door test result was 0.44h-1
ACH @50Pa this surpassed the 0.6h-1
ACH @50Pa which is the requirement
for Passivhaus projects. The tracer gas test (CO2 decay) calculated a value of 0.38 ±0.08h-1
.
The co-heating test result showed performance is even better than design. The total heat loss for both ventilation
and fabric losses was measured to be 35±15W/K, compared to a design target of 63.6W/K, although the weather
conditions for the test were not ideal and it is hoped to repeat the test this winter.
Heat flux sensors were placed on an interior wall and floor to measure the heat flux through the fabric and
therefore measure the respective u-values. The flux measured on the ground slab was 0.099±0.013 W/m2K,
compared to a design target of 0.103W/m2K. The flux measured on the lower wall was 0.097±0.020 W/m2K,
compared to a design target of 0.122W/m2K.
These tests all showed that the Passivhaus standard has delivered a building which has outperformed its design
data, a fact that is unusual in the UK. bere:architects and their independent teams have measured similar results in
all of their other Passivhuas projects.
In-use Data
The university monitoring began in July 2011 and is ongoing. It involves submetering of electric, gas and water
utilities to analyse the energy use. The monitoring also looks at the efficiency of the heat recovery unit, air heating
and solar hot water systems.
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The monitoring shows that the maximum CO2 in the bedroom is <1500ppm, keeping within the max indoor CO2
concentration of 1600ppm quoted by CIBSE Guide A (table 4.2), and 1500ppm quoted by DIN 1946, while in the
living room there were occasional peaks above 1000ppm. The average being 733ppm in the bedroom and 679ppm
in the living room over the period October 2011-August 2012.
From October 2011-August 2012 the average relative humidity range was 41.9% to 53.5%, indicating excellent
internal conditions.
During the first monitored winter in-use, October 2011 to March 2012 (second winter in occupation), the
monitored data showed that the average internal temperature in the house was 21.3°C. The PHPP tool assumes an
indoor temperature of 20°C. When the internal temperature was adjusted in the PHPP to match the actual in-use
temperature, the software predicted higher gas consumption for the period October 2011 to March 2012, than the
actual measured data, and this even remained the case at 20°C. The Passivhaus requirements are for the Specific
Space Heat Demand of the house not to exceed 15kWh/(m2a), our design target was more ambitious at
13.7kWh/(m2a) and the measured performance was 12.2kWh/(m2a) during the first fully monitored 12 month
period, July 2011-July 2012. From the monitoring we know that the occupants are not always interacting with the
building as we expected or planned, for example the external solar blinds are often left down in the winter
reducing the useful solar gains, and the building is still performing better than the design targets. This proves that
with a robust design methodology the building can accommodate varying user behaviours.
The results show that the PHPP is a robust tool for predicting in-use performance. The monitoring will continue
with funding from the Technology Strategy Board for a further full year, then bere:architects intend to support the
continued monitoring of the house with the occupants’ agreement.
Occupant Feedback: Mrs F Terry
“It’s absolutely beautifully warm in here and zero degrees outside. And it’s always got that lovely sort of ambiance
in here. It feels really warm and comfortable and fresh”
“The house works in a very efficient manner because it requires very little heating even when it’s subzero out
there. So it proves that the Passive House concept works - in reality!”
Conclusion
The PHPP provides a robust design tool for accurately design and prediction of energy performance in the UK. The
Passivhaus concept also provides a superior internal environment over minimum standard building regulations.
The occupants of this house have high comfort demands, requiring an average internal temperature of 21.3°C in
winter; however the gas consumption is still below our 20°C design predictions. The occupants say that they feel
very comfortable in summer and winter and that they enjoy the high air quality.
Figure 1: The Camden Passivhaus
7 t h and 8 t h of November 2012
EMCC, The University of Nottingham – Nottingham, UK
60
DESIGNING THE UK’S FIRST PASSIVHAUS ARCHIVE BUILDING
GEORGE MIKURCIK AND JONATHAN HINES
Architype Ltd 01981 542111 [email protected] [email protected]
Introduction
Commissioned by Herefordshire Council to design a new Archive and Records centre, Architype proposed
Passivhaus as the best way to achieve the demanding environmental standards required by the British Standard
for Archive Buildings.
The technical challenge of designing this building were interesting, given the two very different functions of the
main parts of the building:
• an archive store with rigorous and demanding standards in terms of set and constant temperature and
humidity, as specified in British Standard BS 5454
• an office and public areas, with standard office requirements and stringent requirements for spaces for
viewing and restoration of sensitive documents.
We undertook research into recent precedents and found that many archive buildings relied on mechanical
services equipment to moderate the internal environment. We felt that a passive approach would be more robust,
more efficient and more economic in the longer term, and proposed to the client that the buildings should be
designed to Passivhaus.
Testing Passivhaus
The client instructed two options to be fully designed and costed up to C stage – BREEAM Very Good and
Passivhaus. Using the fabric of the building to moderate the internal environment meant that the quantity of
mechanical equipment could be reduced in the Passivhaus option. Avoiding the need for arbitrary renewables
targets, further reduced the requirement for more expensive add on technologies.
This exercise demonstrated that a Passivhaus building would cost 4.5% less to build, than a BREEAM Very good
building, as well as delivering ongoing year on year energy savings. The client opted for the project to proceed as
Passivhaus, as the most logical approach, and design has proceed on this basis.
The project, which is costed at around £6million is currently in detailed design and is due on site early 2013,
subject to political approvals,
The two key parts of the building have very different technical requirements and this led to two different technical
responses. This gave the building a distinctive architectural form, with the archive storage and office/public access
functions conceived as separate forms, linked by an atrium and circulation space.
The archive and records storage building
The BS requirement of archive storage is for a constant temperature below 19 deg C and constant humidity of
between 40 – 55% RH.
We adopted a really simple, passive approach with a well insulated and airtight box separated from the office
block via airlock lobbies.
This building is effectively ‘ground coupled’ to take advantage of relatively stable temperature of the ground to
balance internal temperatures over the period of 12 months. There is minimal insulation below the ground slab,
but good perimeter insulation to minimise heat losses.
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Given the lower than standard required temperature and the difficulty in achieving a fully thermally broken
foundation detail given the heavy loadings of an archive building, this approach was also a pragmatic and cost
effective solution.
The construction is concrete frame, with concrete block infill walls, with a parge coat on the outside to provide
airtightness, which should be a very straightforward/ foolproof construction for this purpose.
The concrete structure and walls are surrounded with a separate ‘duvet’ layer - constructed with ‘larsen’ trusses &
filled with warmcel insulation, and is clad in cedar shingles to break down the scale of the building. This building
has no external windows or doors to the outside. The wall between the archive building and the office building is
insulated to a similar degree as external walls
The aim is to keep the ventilation rates as low as possible, with a target of 0.5 - 1 ac/ day. There may need to be
some form of moisture control incorporated into the system. Recirculated air keeps sufficient heat in the building
whilst keeping moisture out of the archive areas.
The office building
The office building is designed as a standard passivhaus design, similar in construction to Architype’s school
projects.
The foundations are designed to minimise thermal bridging and the construction is a loadbearing timber frame
with a duvet layer made with a ‘larsen’ truss and warmcel insulation.
Generous glazed areas on south elevation provide visual connection with the ground but require additional
shading by brise soleil designed to control solar gain in summer.
Given the use of the building, occupancy levels will be very variable, so we have been careful not to overdesign
and over ventilate in "base" mode. This is being dealt with by having two MVHR systems: one for general
"background" mode and another one to serve public research spaces at their maximum occupancy.
We also had further technical constraints to deal with - UV light must be blocked out, which means that we will
have to apply UV film to all windows, which effectively reduces useful solar gain.
Due to an adjacent busy road, all windows facing south need external acoustic louvers, which effectively reduce
physical free areas.
In summer mode most spaces are naturally ventilated with cross ventilation using the central full height atrium to
draw air through using the stack effect.
Conclusion
This project demonstrates the relevance of Passivhaus in delivering specific and rigorous environmental
requirements at an economic cost, in addition to the low energy and optimized comfort for which it is known.
Figure 1: Perspective of Herefordshire Archive and Records Office showing office and public access in foreground and main archive store to the
rear
7 t h and 8 t h of November 2012
EMCC, The University of Nottingham – Nottingham, UK
62
THE USE OF PASSIVE HOUSE PLANNING PACKAGE TO REDUCE ENERGY USE
AND CO2 EMISSIONS IN HISTORIC DWELLINGS
FRANCIS MORAN, SUKUMAR NATARAJAN, ANDY SHEA
University of Bath [email protected] University of Bath
Since historic buildings constitute 25% of the European built environment they have a role to play in delivering CO2
emissions reduction targets along with the rest of the domestic stock. However, historic buildings have significant
cultural value and were built with technologies and materials that promote fabric breathability to maintain
moisture equilibrium. This demands solutions aligned to the hygroscopic nature of these dwellings to deliver
enduring and radical energy efficiency savings and emissions reduction that while maintaining their heritage value
are capable of district wide replication.
Before embarking on wide scale retrofit adaptations, procedures to assess the potential for such measures to
reduce CO2 emissions are of primary importance. Some measures will have an impact on both fabric and
aesthetics. It is therefore necessary to ensure that the reductions in CO2 emissions from a set of proposed
alterations are significantly higher than any perceived reduction in loss of built heritage.
To achieve large scale market adoption an approach that is both straight forward and effective in assessing CO2
emissions savings from adopting energy efficiency measures is urgently required. This paper demonstrates the use
of the Passive House Planning Package modelling tool to assess the potential for retrofit adaptation measures in
three Georgian terrace dwellings in Bath, England, see Figure 1. It compares delivered against modelled energy use
and then models energy savings following the introduction of a range of retrofit adaptations and Low and Zero
Carbon technologies.
Results indicate that the Passive House Planning Package can effectively assess total electrical energy use but
requires adjustment for occupancy/heating pattern to accurately establish current heating energy consumption.
The modelled results suggest retrofit adaptations in historic buildings could deliver energy savings and CO2
emissions savings between 47-79% when the thermal fabric is significantly improved.
This confirms to some extent what we know, in that without improvement to thermal performance overall
potential for CO2 reduction is reduced considerably. Given the large numbers of historic buildings, current
emissions reduction targets are unlikely to be met without significantly reducing the CO2 emissions resulting from
heating. In the absence of a low carbon heat source suitable for use at the urban scale, improvements to external
wall thermal performance will be required if emission reduction targets are to be met by the historic buildings
stock as a whole.
PHPP presents challenges when attempting to predict current actual energy use. This may be asking too much of a
model that relies on high levels of thermal insulation, low levels of infiltration and MVHR with a constant and
evenly distributed internal temperature in the heating season and applying it to draughty, thermally inefficient and
intermittently heated historic dwellings.
Restrictions arsing from heritage status may mean a number of compromises in achieving full retrofit passive
house certification. This short fall in desired performance highlights that establishing a realistic heating pattern is
key to developing accurate energy and CO2 emissions savings; this applies to all dwelling types. The reality is that
occupants have varying lifestyles and comfort levels. For modelling purposes a standard is defined to enable
comparison. But there is a danger if the standard over estimates energy used for heating as monetary or carbon
savings from retrofit measures may be seriously over estimated.
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The case studies have shown that energy efficiency is not only solely dependent on the performance of the
building, occupants play a vital role. One way to mitigate this effect is to collect empirical data on actual energy
use to improve the accuracy of energy use software prediction. PHPP was developed over time analysing the
results of as built performance against predicted results. Clearly more case study analysis will develop similar
accuracy for retrofit in historic buildings.
Although not strictly part of carbon emissions reduction in the current passive house orthodoxy, the use of PV was
explored. This indicated that emissions savings from electricity could approach 80% depending on occupant
activity. Consequently, although exceeding the maximum heat demand of 15 kWh/m2/a, two of the case studies
used 25% less total primary energy that a Passivhaus complaint (EnerPHit) solution.
PHPP has shown that as a model it can provide assessments of the benefits of retrofit adaptations in historic
buildings. But more importantly and with regard to aligning the conservation of energy to the conservation of
heritage, it can provide empirical data to evaluate the benefit of decisions that affect fabric and/or aesthetics.
Figure 1: Grade II listed buildings modelled using PHPP
7 t h and 8 t h of November 2012
EMCC, The University of Nottingham – Nottingham, UK
64
REFURBISHING THE EXISTING HOUSING STOCK USING PASSIVHAUS
STANDARDS
JOHNATHAN NEA
Climate Change is affecting our environment and here in the UK we are trying to take a proactive approach to
reducing CO2 emissions. The Climate Change Act was introduced in 2008 and CO2 reduction targets, which the UK
must meet, have been set. The aim of the Act is to reduce the UK Carbon emissions by 80% on 1990 emission
levels by 2050. To achieve the government aspirations, changes will be seen in every sector of the economy. The
residential sector changes will affect everyone in the UK as some form of retrofit works will be required to
everyone’s home.
The greater driver for the majority of people will be to reduce their annual fuel bills. Fuel poverty has become a
real problem in the UK and it is estimated there are approximately 3 million people affected in 2009 (DECC, 2012).
The UK has a very diverse housing stock with 21% of dwellings built before 1919 and 16% between 1919 and 1945
(DCLG, 2010, p. 10). There are 20.1 million homes that could benefit from energy improvement works,
recommended under the Energy Performance Certificate (EPC) methodology. Orbit has carried out works that go
beyond the EPC recommendations to a number of hard to treat properties. This presentation will look at how a
number of different property types can be refurbished using Passivhaus principles, which will reduce fuel poverty
and CO2 emissions.
277 Foleshill Road, Coventry
The property is a Pre 1900’s mid terrace house located in Coventry. This project was Orbit’s first passive
refurbishment project. The aim was to improve the efficiency of the property, although no desired kWh/m2/yr.
figure was set The purpose was to employ passivhaus principles to determine if it is a viable option to apply to a
larger proportion of the stock.
56 & 58 Elliott Drive, Warwickshire
The project consisted of two 1950’s, wimpy no fines semi detached houses. Number 58 was refurbished to the
Enerphit Standard which has a space heating demand of 25kWh/m2/yr. Whereas number 56 was refurbished to a
more modest standard consisting of general void works plus thermal upgrades, a space heating demand of
100kWh/m2/yr. was set.
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External insulation works to 90 Properties
Orbit have taken advantage of CESP scheme (Community Energy Saving Programme) and externally insulated Pre
1900’s properties. Where possible Passivhaus principles have been employed to improve the air tightmess of the
buildings.
The three projects demonstrate different measures which employ passivhaus principles to improve the energy
efficiency of the existing housing. The presentation will go into further detail on these three projects and the
technologies installed, improvement in energy efficiency and CO2 emissions. Improving the energy efficiency of
the UK housing stock using measures similar to the ones in Orbit project will reduce energy consumption, fuel
poverty and carbon emissions. It is very difficult to adopt a one fit solution for all but the passivhaus standard
offers a methodology that can be applied to a large porportion of properties.
References
DCLG. (2010). English housing Survey - Housing stock report. London: Department for Communities and Local
Government.
DECC. (2012). Hills Fuel Poverty Review. Retrieved September 13, 2012, from http://www.decc.gov.uk
/en/content/cms/funding/Fuel_poverty/Hills_Review/Hills_Review.aspx
7 t h and 8 t h of November 2012
EMCC, The University of Nottingham – Nottingham, UK
66
PASSIVHAUS RETROFIT OF A 1970’S TOWER BLOCK IN HAVERING,
EAST LONDON
JOHN PRATLEY, PAUL SMYTH
Sustainable By Design LLP, [email protected]
Cocreate Consulting, [email protected]
In February 2012, Cocreate Consulting and Sustainable By Design LLP were commissioned by the Park View Estate
Tenants’ & Residents’ Association (PETRA) to undertake a Feasibility Study of the energy efficient upgrade of three
tower blocks at Park View Estate in Havering, East London.
The tower blocks were in a reasonably good state of repair but had poor thermal performance and residents were
reporting high heating bills and un-healthy living conditions within the 144 flats - including damp, draughts and
condensation problems.
At the time, PETRA was in discussion with the Local Authority and a number of Council-approved, independent
green retrofit suppliers about different refurbishment options that could improve their living environment, but felt
that the discussions were being progressed without a proper, holistic understanding of the energy performance or
construction limitations of the tower blocks as a whole.
Cocreate Consulting advised PETRA that the Passivhaus EnerPHit Standard is Europe’s leading energy performance
criteria for building refurbishment and that the Passivhaus Planning Package (PHPP) would be the best total-
building energy modelling tool for predicting the tower blocks’ current operational energy demand.
Cocreate Consulting and Sustainable By Design LLP therefore embarked on an overview of the existing building
performance and proposed retrofit recommendations to achieve reductions in energy use to meet the EnerPHit
Passivhaus Refurbishment space heating standard of less than 25 kWh/m2/yr.
Our joint role was to provide initial PHPP modelling, technical construction sketches and an outline specification
with suggested phased retrofit improvements. The purpose of the modelling exercise was to consider the practical
issues of a whole building refurbishment, quantify potential energy savings and propose pragmatic and affordable
recommendations for how the local Estate Tenants' & Residents' Association can improve their living environment.
The overview of the existing construction included an initial visual survey of one of the existing towers, Park View
House, and interviews with the existing residents, some of whom had lived in the tower block since it was first
occupied forty years ago and therefore had a record of the building’s performance and maintenance over that
time.
The three, 13-storey tower blocks had been built in the early 1970’s and are typical of their time: with a system-
build construction incorporating pre-cast concrete wall panels, in-situ concrete floor slabs with load-bearing brick
cladding from floor to floor. All 48 flats per block are clustered around a central, vertical circulation core with steel-
framed, single-glazed windows, no insulation in the cavity behind the brick wall cladding and a failed mechanical
ventilation and air-heating system which was in the process of being replaced by individual gas boilers and
radiators with communal extract fans.
From this initial investigation, measured drawings were produced with technical sketches and performance
specification notes of the existing construction – providing enough building and occupant information to allow for
an initial PHPP model to be progressed, resulting in an existing space heating demand of over 200 kWh/m2/yr. This
tallied with the high heating bills that were being reported by the residents.
The Study focused on the following areas of construction and specification: Elevations/External Wall, Balconies,
Ground Floor, Roof, Windows, Ventilation, Heating and Air Tightness.
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Possible improvements to these areas were investigated – including technical sketches and designs of typical
details and improved performance specification notes, culminating in a completed PHPP model incorporating
retrofit measures to achieve the EnerPHit standard of less than 25kWh/m2 space heating demand.
Finally, the improved Outline EnerPHit Specification and technical sketches were then discussed with the
independent Green Retrofit suppliers to create a set of Practical Retrofit Proposals to test for costing and
programme consequences.
The Feasibility Study concluded with a summary Outline Passivhaus EnerPHit Specification within an incremental,
pragmatic Retrofit Phasing Programme - linked to PHPP predicted improvements in space heating demand and
future funding requirements.
PETRA, the local Estate Tenants' & Residents' Association, are now using this Study to inform their discussions with
the Local Authority based on a pragmatic understanding of what effective retrofit measures are available, at which
stage of refurbishment they are appropriate, and how these measures can improve the energy performance of
each tower block as a whole – potentially reducing each resident’s heating bills and giving them more comfortable,
healthy living conditions.
Figure 1: Park View House, Havering, East London
7 t h and 8 t h of November 2012
EMCC, The University of Nottingham – Nottingham, UK
68
CONSTRUCTION OF RICHMOND HILL PRIMARY SCHOOL
The UK’s first Passivhaus on piled foundations
JIM SHAW
Interserve Construction Limited [email protected]
Richmond Hill Primary School is the largest Passivhaus building in the UK. Built to expand and replace the existing
ageing buildings on the outskirts of Leeds city centre on a brownfield site, the project presented a number of
challenges for the design and construction team.
The Client, Leeds City Council, wished to reduce carbon emissions in their new buildings and Passivhaus was
selected as the method to achieve this. However, the functional design and layout of the building remained their
priority – educational and access needs took precedence.
The building is constructed over a former quarry, requiring a piled foundation to support the large steel-framed
structure. Innovative use of high-strength insulation normally found in petrochemical installations minimised cold
bridging at high load parts of the foundation. A number of braced bays for the steel frame could not be eliminated
and these were taken straight to the pilecap with the cold bridge modelled. To compensate for this, exceptionally
thick polystyrene insulation was used under the remainder of the suspended ground floor slab. These complex
foundation solutions required attention to detail during construction to ensure that high installation standards
were achieved.
Utilising a steel frame ensured the design and layout flexibility met the Client’s needs and assisted with the
support of a SIP-based thermal envelope. Whilst the steel frame allowed the creation of the internal spaces
needed, it introduced point loads to the foundation and also made air-sealing more complex. A variety of methods
were employed to accomplish effective air sealing.
With the design stage PHPP arriving right on the limit at 15.4kwh/m2/year, the team set about improving the
component performance, remaining wary about reliance upon reducing the air-permeability to achieve
certification. Improvement in thermal performance of key products was reviewed and enhanced, including the
commissioning of bespoke testing to evidence the benefit.
Achieving the air permeability required for Passivhaus certification substantially raises the bar in comparison with
conventional UK building practice. The Interserve team were conscious of this significant construction-stage risk.
A considerable effort was made by the Architect, _Space Group, and Interserve’s pre-construction team to ensure
this was achievable, concentrating in great detail on the construction method, sequence and accessibility of
membranes.
Key suppliers where involved in the evolution of the project design and a genuine spirit of collaboration was
fostered.
The pre-construction design and planning was backed up on site by a thorough approach to monitoring and
recording the works. The eventual air permeability of 0.25 a.c.h. reflects this forethought and the quality-focussed
culture that had been engendered.
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Figure 1: Richmond Hill Primary School by Interserve Construction Limited
7 t h and 8 t h of November 2012
EMCC, The University of Nottingham – Nottingham, UK
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BRIDGING THE THEORY: REALITY GAP
MARK SIDDALL, DAVID JOHNSTON
Northumbria University, Newcastle, UK and LEAP: low energy architectural practice
([email protected] +44(0)7795031700)
CeBE, Leeds Metropolitan University, Leeds, UK
It has been increasingly recognised within the UK that buildings, as-constructed, are not performing in accordance
with theory and that one of the reasons for this performance failure can be attributed to unaccounted thermal
bypass (ZCH, 2010 and Stafford et al., 2012). The lead author has previously presented papers reporting upon the
impact that Convective Thermal Bypass mechanisms can have on building performance (see Siddall, 2009 and
2011). In 2009, the author contended that constructing Passivhaus buildings without dedicating due care and
attention to thermal bypass mechanisms could result in building performance failures.
This paper discusses the results obtained from a small number of coheating tests that have recently been
undertaken on Passivhaus dwellings. These results suggest that the Passivhaus standard, when complimented by
an appreciation of the risks imposed by thermal bypass, is capable of closing this performance gap.
Coheating Tests : Results
A coheating test is a quasi-steady state method that can be used to measure the whole dwelling heat loss (both
fabric and background ventilation) attributable to an unoccupied dwelling in W/K. The process involves using
electric resistance heating to achieve a mean elevated indoor air temperature of approximately 25°C for an
extended period of time; in this case approximately 4 weeks. The daily amount of electrical energy that is used to
heat the building is measured and then used to determine the heat input in Watts (W). By plotting the daily energy
demand (W) against the daily mean temperature difference between inside and outside (ΔT) the heat loss
coefficient (HLC) may then be determined (W/K).
Two dwellings that form part of the recently completed Passivhaus Racecourse development at Hutton Rise,
Houghton-le-Spring, Sunderland have just recently undergone a coheating test. The results of the coheating tests
(see Figures 1 and 2) have demonstrated a very high level of correlation between the as-designed performance
and the as-built performance. Fig. 1 illustrates the results from regression analysis and serves to demonstrate “that
the measured and predicted heat loss coefficient for dwelling 1 are in very close agreement with one another
(46.7W/K as opposed to the design of 43.4W/K), with the difference in heat loss coefficient being well within the
range of the measurement error associated with the test” (Johnston, 2012a). Fig. 2 compares Racecourse dwellings
1 and 2 (far right) with 22 dwellings from the Leeds Metropolitan University coheating database. It can be
observed that the performance gap between predicted and measured performance has been closed significantly.
Fig 1: Solar and wind corrected heat loss data for dwelling 1
Fig 2: Measured versus predicted heat loss coefficients for 22 dwellings
from the Leeds Met database
y = 46.646xR² = 0.844
0.00
200.00
400.00
600.00
800.00
1000.00
1200.00
1400.00
0.0 5.0 10.0 15.0 20.0 25.0
Power (W)
Delta T (K)
Corrected data
Predicted
Data corrected for solar and wind. Wind added back in @ 2.9ms-1.
0.00
50.00
100.00
150.00
200.00
250.00
300.00
He
at
loss
(W
/K)
Predicted
Measured Passivhaus Dwellings 1 & 2
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Coheating Tests : Contextualised
From this very limited study at the Racecourse, it would appear that, with an adequate understanding and
appreciation of thermal bypass mechanisms, and diligent accounting of the conductive and radiative heat losses
that are addressed by PHPP, it is possible to deliver building envelopes that perform as predicted. The author is
conscious that the positive results at Racecourse could be viewed as good fortune, rather a result of careful
planning. In essence, this raises the question whether similar results can be achieved in diverse geographic
locations with different clients, designers and construction teams.
To begin to address this question, it is necessary to draw upon coheating tests that have been undertaken on other
Passivhaus dwellings. It should be noted that these coheating test methodologies were undertaken by other
parties and that the coheating methodologies have not yet been normalised, which could lead to uncertainty with
regard to both the results and their interpretation. These matters notwithstanding, the author has complied data
from coheating tests from other Passivhaus dwellings. Table 1 presents these results. Unfortunately treated floor
area and form factor data were not available at the time of writing, and as a consequence it has not been possible
to present, or analyse, the data as a heat loss parameter.
Predicted (W/K) Measured (W/K) Error compared to
target (W/K) Dwelling Type
Racecourse Dwelling 1 (Johnston, 2012a) 43.4 46.7 +3.3 (+7.6%) Terrace
Racecourse Dwelling 2 (Johnston, 2012a) 36.6 38.1 +1.5 (+4.0%) Terrace
Larch House (Tweed, 2011) 57.6 60 +/- 14 2.4 (+4.1%) Detached
Lime House (Tweed, 2011) 37.2 41 +/- 8 3.8 (+10.2%) Detached
Ford Close (Warm, 2012) 45.6 50.4 4.8 (+10.5%) Terrace
Ranulf Road (Stamp, 2011) 63.6 35 +/- 15 -28.6 (-55%) Terrace
Table 1: Coheating Test results for Passivhaus dwellings in the UK
The results from the Ranulf Road case study suggest that heat losses are half of those predicted; it is understood
that the test results were compromised by high levels of solar gain and insufficient temperature difference
(between inside and outside) being maintained for the duration of the test. For this reason, the results of that
study are considered to be an outlier and should be excluded from the analysis.
Whilst the availability of coheating data is currently limited, and due to lack of normalisation the comparability of
the results questionable, a certain amount of confidence can be found within the studies presented. Should it be a
concern that the heat loss is between 3.3% and 10.5% greater than expected? To answer this question a little
context is required. The measured mean increase in heat loss from the Passivhaus dwellings is 3.16W/K. In
contrast, the highest measured heat loss from any new-build dwelling contained within the Leeds Metropolitan
University coheating test dataset was found to be some 282W/K against a predicted total heat loss of 225W/K (see
left hand side of fig 2). Putting aside issues of form factor for a moment (which can influence the as-built whole
house heat loss coefficient), it can be recognised that 3.16W/K is approximately 1% of the heat loss from the UK
Building Regulations Part L 2006 compliant dwelling. In this context, it is contended that such minor errors may be
considered trivial.
Conclusions: Does the Passivhaus Standard guarantee performance?
The UK Passivhaus projects that have undergone coheating tests have all considered the risks imposed by thermal
bypass and have developed their design and construction processes accordingly. In this respect it cannot simply be
stated that the Passivhaus Standard, as it stands, will guarantee performance. It can be concluded however, that
Passivhaus Standards of quality assurance appear to work well when complimented by an appreciation of the
potential impact of convective thermal bypass. Coheating is a useful means of deriving the measured value of the
whole house heat loss (fabric and ventilation losses heat losses), though careful interpretation of the results is
required in order to derive useful comparisons between dwellings and test conditions. A normalised method for
undertaking coheating tests and analysing the results of such tests would be beneficial as this would aid
comparability and reduce methodological differences, thus increasing certainty with regard to both measured
results and analysis of data.
7 t h and 8 t h of November 2012
EMCC, The University of Nottingham – Nottingham, UK
72
EXPERIENCES AND LESSONS FROM
THE DENBY DALE PASSIVHAUS
Examining two years’ monitoring data and occupant feedback
RUTH SUTTON, CHRIS HERRING
Leeds Metropolitan University, [email protected]
Green Building Store, [email protected]
Energy consumption data, environmental data and interviews have been used to assess the performance of the
Denby Dale Passivhaus which has been occupied for two years since its completion. The occupants have been
keenly observing, monitoring and responding to the performance of the house over this period, during which
contact has been maintained with the developers, Green Building Store (GBS). As the first passivhaus built by GBS,
and one of only a few in the UK, there has been significant learning over this time which is presented here.
In May 2010, the clients, moved into the house in Kirklees, West Yorkshire. Built by GBS to meet their
requirements for “...a comfortable house, with low running costs”, the project is a detached masonry cavity
dwelling, certified to the Passivhaus standard. The dwelling is connected to mains gas and electricity which
supplement the thermal and photovoltaic solar panels.
Monthly gas and electricity consumption and readings from PV panels and solar thermal meters were collected by
the householder, from May 2010 to May 2012. Environmental conditions were monitored at 10 minute intervals,
from June 2010 to May 2012, by Leeds Metropolitan University (LMU). Tinytag sensors, measuring temperature
and relative humidity were placed in the kitchen, lounge, study, bedroom and bathroom. Carbon dioxide was
measured in the bedroom and lounge. External temperature and relative humidity data were also collected over
this period.
Discussions were held with the householder throughout the monitoring period about the management of the
dwelling. At the end of the monitoring period, a meeting was between the researchers, the householders and GBS
to discuss the householders’ experience over the two years and to explore some of the findings.
The energy consumption and production of the dwelling is shown in the table below; it is noted that not all of the
energy measured for the PV and the solar thermal will have been utilised by the household. Total consumption is
close to the specific primary energy demand predicted by the Passivhaus planning package. It is estimated that
800-1500kWh of gas was used for cooking on the hob. Gas used for hot water, during the heating season is in the
range 500-1000kWh. Some electricity consumption occurred outside of the thermal envelope and as such did not
contribute to thermal gains; an electric heater and power tools were used in the garage for long periods
throughout winter months. In December 2010/ January 2011, heating was used in the garage to defrost the MVHR
condensate pipe during a particularly cold spell. Error! Not a valid link.There was no formal handover process but
both GBS and the householders recognised that an informal handover has continued over an extended period.
Through involvement in the design of the dwelling, the householders have developed an understanding of how the
building works. This was reflected in their use of the dwelling. They were aware of the need to use blinds to
prevent overheating during the summer, the impact of the large thermal mass in the dwelling on its
responsiveness and the use of the summer bypass. It has taken time to learn how to maximise the comfort from
the dwelling; although they were keen to emphasise that it is not a difficult home to manage.
The MVHR system represented a new system to the householder. On moving into the dwelling, the occupants had
read the manual but had found it difficult to digest, with information for installer and user mixed together. During
the first heating season, the householder noted that they were suffering from low humidity levels, especially in the
bedroom at night. Daily mean values of relative humidity were below 40% throughout December, with minimum
values identified below 35%. This dryness was combated by the ho
back of the chair; later rereading of the MVHR manual identified that flow rates should be reduced during winter
months. Conditions have not repeated in the second heating season. More clear information for the u
prevented the problem encountered in the first year.
A key finding for GBS is with respect to the heating design. When options for the heating system were considered,
GBS explored a number of alternatives. A number of factors were instrumenta
including: budgetary constraints; the clients’ wishes for a minimal number of radiators; and lack of ‘off the shelf’
low capacity boilers available in the UK. The resulting compromise was an over
boiler serving a duct heater, 1 radiator and 2 towel rails, at very low water volume.
As a result, problems were experienced in the first year leading to overheating, short cycling of the boiler,
and decreased boiler efficiency. Air temperature throu
range of temperature across the dwelling. Maximum temperatures were found in the bathroom and the lounge,
where radiators are located. The owners also reported finding it difficult to control tempe
2011, a weather compensator was fitted to control boiler modulation which has delivered improved control of
temperatures across the dwelling and is expected. However, mean temperatures remained above 21°C indicating a
preference by the householders for temperatures above that described by the Passivhaus model.
• The Denby Dale Passivhaus is performing well and energy consumption is close to that predicted in
Passivhaus planning package.
• Monitoring data from the first two y
important factor in Passivhaus performance. Passivhaus principles and MVHR systems may be unfamiliar
to many UK householders and the project has illustrated that occupants need a reasonable le
understanding of how the house and systems work in order to optimise comfort and performance. Formal
handovers with clear instructions for occupants of Passivhaus buildings are required in cases where
clients have no involvement in the design of the
• Problems with the over-capacity boiler have illustrated the importance of careful specification of heating
systems in Passivhaus buildings.
Figure 1: The Denby Dale Passivhaus Energy consumption profile
values identified below 35%. This dryness was combated by the householder by using dampened towels over the
back of the chair; later rereading of the MVHR manual identified that flow rates should be reduced during winter
months. Conditions have not repeated in the second heating season. More clear information for the u
prevented the problem encountered in the first year.
A key finding for GBS is with respect to the heating design. When options for the heating system were considered,
GBS explored a number of alternatives. A number of factors were instrumental in deciding the final system,
including: budgetary constraints; the clients’ wishes for a minimal number of radiators; and lack of ‘off the shelf’
low capacity boilers available in the UK. The resulting compromise was an over-capacity (4.8 kW) condensing
boiler serving a duct heater, 1 radiator and 2 towel rails, at very low water volume.
As a result, problems were experienced in the first year leading to overheating, short cycling of the boiler,
decreased boiler efficiency. Air temperature throughout the first heating season is characterised by a broad
range of temperature across the dwelling. Maximum temperatures were found in the bathroom and the lounge,
where radiators are located. The owners also reported finding it difficult to control tempe
2011, a weather compensator was fitted to control boiler modulation which has delivered improved control of
temperatures across the dwelling and is expected. However, mean temperatures remained above 21°C indicating a
the householders for temperatures above that described by the Passivhaus model.
Conclusion
The Denby Dale Passivhaus is performing well and energy consumption is close to that predicted in
Passivhaus planning package.
Monitoring data from the first two year’s habitation have illustrated that occupant behaviour is an
important factor in Passivhaus performance. Passivhaus principles and MVHR systems may be unfamiliar
to many UK householders and the project has illustrated that occupants need a reasonable le
understanding of how the house and systems work in order to optimise comfort and performance. Formal
handovers with clear instructions for occupants of Passivhaus buildings are required in cases where
clients have no involvement in the design of the dwelling,
capacity boiler have illustrated the importance of careful specification of heating
systems in Passivhaus buildings.
Figure 1: The Denby Dale Passivhaus Energy consumption profile
73
useholder by using dampened towels over the
back of the chair; later rereading of the MVHR manual identified that flow rates should be reduced during winter
months. Conditions have not repeated in the second heating season. More clear information for the user may have
A key finding for GBS is with respect to the heating design. When options for the heating system were considered,
l in deciding the final system,
including: budgetary constraints; the clients’ wishes for a minimal number of radiators; and lack of ‘off the shelf’
capacity (4.8 kW) condensing gas
As a result, problems were experienced in the first year leading to overheating, short cycling of the boiler,
ghout the first heating season is characterised by a broad
range of temperature across the dwelling. Maximum temperatures were found in the bathroom and the lounge,
where radiators are located. The owners also reported finding it difficult to control temperatures etc. In December
2011, a weather compensator was fitted to control boiler modulation which has delivered improved control of
temperatures across the dwelling and is expected. However, mean temperatures remained above 21°C indicating a
the householders for temperatures above that described by the Passivhaus model.
The Denby Dale Passivhaus is performing well and energy consumption is close to that predicted in
ear’s habitation have illustrated that occupant behaviour is an
important factor in Passivhaus performance. Passivhaus principles and MVHR systems may be unfamiliar
to many UK householders and the project has illustrated that occupants need a reasonable level of
understanding of how the house and systems work in order to optimise comfort and performance. Formal
handovers with clear instructions for occupants of Passivhaus buildings are required in cases where
capacity boiler have illustrated the importance of careful specification of heating
7 t h and 8 t h of November 2012
EMCC, The University of Nottingham – Nottingham, UK
74
THE UGLY DUCKLING
(OR ENERPHIT PROJECT IN SLOVAKIA)
KIM WILLIAMS
Carbonreduction.eu, [email protected]
In this project an ‘abandoned’ family house located in Slovakia (Figure 1) was renovated to meet the EnerPHit
criteria for residential-use refurbished buildings. The house was in extremely poor condition at the outset and the
aim of the project was to gain practical experience in an EnerPHit refurbishment and the use of ground-air heat
exchanger techniques.
According to Royal Institute of British Architects in their Climate Change Toolkit (01 Climate Change Briefing,
second edition, 2009) energy use in buildings accounts for almost half of all UK CO2 emissions. Energy use in
housing accounts for more than half of these emissions, i.e. 27% of total UK emissions. The replacement rate of
the existing housing stock is estimated to be <1% per year, thus emissions from the existing stock account for
almost all of the emissions – 99.7%. The briefing points out that at the existing rate of replacement 80% of existing
dwellings will still exist in 2050, making it impossible for the UK to meet its carbon emissions reduction targets
without an extensive programme of improvements to the energy efficiency of existing dwellings. Within the EU as
a whole, the housing stock replacement rate is estimated to be between 1 – 1.5%
In the UK space heating accounts for 60% of domestic energy consumption (Energy consumption in the United
Kingdom: 2012, DECC). In Slovakia (where this EnerPHit project is located) heating represents 80% of total final
energy consumption in the residential sector (Energy Charter Secretariat, 2009).
“The use of Passive House components in refurbishments of existing buildings leads to extensive improvements
with reference to thermal comfort” and “a reduction of the heating demand by 90% was achieved in a large
number of projects.” (Passive House Institute, website).
It is in this context that the EnerPHit standard for refurbishing existing buildings is of relevance.
The building is of solid block construction with a full height basement. An external wall insulation system
comprising 25cm EPS was installed (30cm EPS to roof). The ground around the house was excavated to foundation
level and 30cm of EPS installed around the basement. The opportunity was taken to install a ground-air heat
exchanger since there was minimal additional cost involved. A 10cm layer of EPS was laid above the heat
exchanger pipe to simulate additional depth (thermal shadow) as described by Walter Jeffries in his article on
Earth Air Tubes (Sept 2008, http://sugarmtnfarm.com/2008/09/05/earth-air-tubes/).
Windows were replaced with high performance triple glazed UPVC units with insulated frames and a high
efficiency (85%) MVHR unit was installed. The PHPP was used to determine the optimum insulation and glazing
combinations for meeting the maximum heat demand (25W/m2/year). THERM was used to model construction
details and the effects of different insulation thicknesses.
The preliminary ‘predicted’ energy performance is less than the 25W/m2/year necessary to meet EnerPHit
standard. The Slovak building energy rating system (EPC) classes a family house with annual energy consumption
of up to 54kWh/m2/year as ‘A’ (Passive House). On the other hand the UK EPC rating system rates dwellings on the
basis of energy cost – the SAP rating. The SAP rating is expressed as a number from 1 – 100 (divided into band A-G)
and is based on the energy costs of space heating, water heating, ventilation and lighting minus cost savings from
energy generation technologies. Although the EPC certificate includes an estimate of annual energy use per m2 of
floor area it is not comparable with the Slovak model.
75
Correct installation of the windows was the only major issue experienced. Although all parties involved in the
buying process had nodded knowingly when the ‘special’ needs of the installation were discussed it was soon
evident on site that the window fitters had little idea of how to install a window properly. It was therefore decided
to go ‘hands on’ and take personal responsibility for installing the windows. The fitting of the external parapets
raised questions about the thermal performance of the mechanical interface - this is being investigated.
Whilst the companies involved on the project had heard of ‘Passive House’ they didn’t have practical experience of
working to the standards required to achieve the required air tightness. On the plus side the building team
selected were very interested, researched the topic independently and made every effort to deliver on site. The
window company selection was not so fortuitous –the quality of the actual windows was very good but the
suppliers proved totally incapable of making a good installation. Whilst a satisfactory installation appears to have
been effected (the proof will be in the air test – yet to be completed - and subsequent performance) this aspect
could easily have gone very badly. In future projects it may be more prudent to procure the major items and their
fitting through the main contractor who would then take responsibility for proper delivery and installation.
A further (surprise) discovery was the difficulty in finding tools for calculating the potential energy benefits for the
ground-air heat exchanger together with a lack of published user experiences with this particular technology. The
little evidence available (i.e. found) and calculations on energy yield suggested the ground-air heat exchanger was
not an economic option for this project; however, as the ground around the building was to be excavated in any
case, it was decided to install the option and to implement a monitoring programme to report on the performance
over time. There is no conclusion to this question (or the project as a whole) at the time of writing. The works
should be completed in time for the winter period when energy and building performance can be measured and
monitored.
Figure 1: The Ugly Duckling – family house in Slovakia
7 t h and 8 t h of November 2012
EMCC, The University of Nottingham – Nottingham, UK
76
LANCASTER COHOUSING PROJECT - SMALL SCALE RESIDENTIAL
DEVELOPMENT INCLUDING COSTS
ANDREW YEATS
Eco Arc Architects [email protected]
Lancaster Cohousing Project is a certified Passivhaus / CSH Level 6 and Life Time Homes, affordable community
housing project, which has evolved through a participatory design process with the individual householders and
Eco Arc Architects.
Work is about to finish the largest certified Passivhaus ‘Cohousing’ project in the UK with forty one individual
households ranging from one bed flats to three bed family houses, all with shared community facilities. Lancaster
Cohousing has created a new eco-community; small enough for everyone to know each other, yet big enough not
to be claustrophobic. Crucially the size allows households to do a lot towards reducing their carbon footprint that
would not be possible for a single family, or a scattered group of households.
The project has all the typical features of Cohousing, a way of living pioneered in Denmark but now growing in
many countries. i.e. building small houses with extensive common facilities while designing the site to encourage a
strong sense of community. Residents have been involved in the design process and will manage the site when
they moved in. The design has grown to 41 households over the course of several years as an intergenerational
community. The project includes shared facilities such as offices, guest bedrooms and laundry facilities, enabling
many households to choose a smaller home than they would otherwise want. This reduces both energy in use and
embodied energy. Residents are offered on site workspace at favourable rates to reduce the amount of
commuting.
The householders that had joined the scheme spent a several years developing the designs with the project
architect Andrew Yeats of Eco Arc and working with the specialist design team including Alan Clark, Nick Grant and
Peter Warm on the Passivhaus design aspects and Eric Parks on the Code for Sustainable Homes & Life Time
Homes aspects.
The new homes have been designed & built to meet the certified Passivhaus standard:
• Minimise heat loss – super insulation, triple glazing, compact terrace built form.
• Minimise ventilation heat loss – heat recovery ventilation and airtight construction,
• Optimise solar gain for winter heat.
Energy use for heating is less than 15kWh/m2 per year, achieved through very careful attention to airtightness and
thermal bridging, and the use of an efficient ventilation system with heat recovery.
Domestic hot water & hot water to feed a single radiator in each house is supplied via a centralised woodchip
district heating boiler system, pre-heated using solar thermal panels. The fuel comes from managed woodlands in
Lancashire and Cumbria.
77
Electricity is supplied via a private network from photovoltaic panels on the south facing roofs and a 220kW hydro
turbine in the River Lune. This will easily make the project zero carbon, but it hasn’t stopped the design doing
everything possible to minimise demand.
Cohousing developments keep cars to the edge of the site. As transport is a significant proportion of most
households’ carbon footprint an ambitious residential travel plan has been set up including a share scheme, with
one car per three households. Initially the scheme will be run using members existing private cars, but these will
be replaced by electric vehicles over time.
The Lancaster Cohousing project demonstrates a viable holistic option in which to deliver affordable Passivhaus
designs in the UK, taking in to account wider sustainability and social community issues as well as PH standards re:
personal comfort and low energy demand.
Figure 1: The Lancaster Cohousing Project by Eco Arc Architects, Alan Clark, Nick Grant & Whittle Construction –
Works In Progress: On Terrace A The First 6 Units Of 41 Houses To Be Handed Over To The Community Group Client.