Hard-to-treat homes 11 May 2005 Tackling Hard-to-treat homes Heat pumps, solid wall insulation and non-traditional construction

Hard-to-treat homes 11 May 2005

Tackling Hard-to-treat homes

Heat pumps, solid wall insulation and non-traditional

construction


Energy Efficiency Partnership for Homes

Three research exercises commissioned by the Hard-to-treat homes sub-group:

Solid Wall Insulation: Impetus, 2004 Heat Pumps: People for Places, 2005 Non-traditional construction: CSE, 2005


Fuel poverty and non-traditional

construction

Ian Preston, CSEDr Richard Moore


Background

~1 million non-traditional properties in UK Majority built between 1945 the and early 1970s Over 500 systems built between 1919 and 1976 Termed system-built or pre-fabricated Four broad categories, by wall construction Thermal efficiency varies significantly In practice, the majority of investment was

designed to overcome defects


Aims of study

Investigate how many non-traditionally constructed homes still exist in the UK

Identify the risk of fuel poverty within them

Identify examples of best practice and potential case study areas


Methodology

Produce estimates of SAP and fuel poverty from all four national HCSfor 80 proprietary systems

Analysis by nation, sub-category, and where possible proprietary system

Results for Scotland and Wales are limited by the design and in the case of Wales by the quality of their HCS


Methodology (cont.)

Estimates of NTH for each local authority

Compilation of database from a range of sources

Identified 52 authorities with high levels of NTH

Contacted the management body to establish works undertaken, and the associated changes in SAP or risk of FP


Sample resultsWallconstruction in England

Total households (x 1000)714

234

479

13,672

5,411

Cavity wall Solid wall

Masonry crosswall Non-trad low-rise

Non-trad high-rise


Non-masonry homes

(x1000)

Non-masonry homes (x 1000)

143

245

54

321

41

132

72186

Old timber frame New timber frameMetal frame Insitu boxwallPrecast boxwall Precast frameInsitu frame Concrete crosswall


SAP ratings by construction

0

20

40

60

80

100

120

Mas

onry

soli

d wal

l

Non-tr

aditio

nal lo

w-rise

Non tr

ad h

igh/ m

ediu

m ri

se

Mas

onry

cav

ity w

all

Mas

onry

cro

ss-w

all .

Pre 1

919

timbe

r fra

me

Met

al fra

me

Preca

st co

ncre

te fr

ame

Post 1

919

timbe

r fra

me

Concr

ete

cros

swal

l

Per

cen

tag

e/ S

AP

rat

ing

SAP < 35 SAP 35-65 SAP 65 plus Worst 10% Average SAP

V 3

WO

RS

T &

2 B

ES

T T

YP

ES

V


LA survey

19 out of 52 authorities contacted responded 18 respondents (95%) provided numbers of non-

traditional houses (LA or LSVT) 14 supplied details of the improvements made 11 provided indicative figures for average work costs Only 6 had estimates for changes in SAP ratings, None commented on the effects of improvements on

fuel poverty


LA Survey

Significant levels of improvement works have been carried out on all non-traditional stock

Typical measures include; EWI or replacement brick cavity walls, LI, central heating and new kitchens and bathrooms

Majority of investment between 1980s and 90s, but there is a significant amount of ongoing maintenance and improvement

Estimated cost of works varies significantly, i.e. from £3,000 to £80,000


LA survey

Cost of improvements and the value of property is a factor in an authority’s decision to improve them i.e. Rugby Borough Council

A comprehensive package of measures is required to a target SAP rating of 65 or above

An average cost of £10,000 provides a good indication of expenditure required per property*

Costs can be significantly higher when structural work is required to improve or replace walls


Study of heat pumps for Hard-to-treat homes

Nicholas Doyle, Places for peopleAlan Pither


Aims

Report on application of heat pumps to hard-to-treat homes

Guidance to local authorities, architects and developers


Outputs

Main heat pump technologies Commercial providers Applicability of the technology Case studies Application matrix Initial guidance


Methodology

Literature review Database Interviews with key people

Questionnaire 1: Companies Questionnaire 2: Utilities Questionnaire 3: Users


Database

UK Heat Pump Network Heat Pump Association Ground Source Heat Pump Club Clear Skies Now most up to date Dbase


Key interviews

Heat Pump Association Manufacturers, Installers and

Suppliers Energy Companies Landlords Ground Source Heat Pump Club


Findings

Supplier and installer Member of HPN Majority of Technology is G2W plus

W2W Operates throughout UK and

occasionally outside Market split evenly between HA, LA and

individual householders Majority of work in newbuild Definitely doesn’t believe that HP can be

used in HTT - one exception


Findings

Cautious Overloaded with research Industry changing fast A tipping point?


Utilities survey

All EEC managers called Only 2 responses Cautious – commercially sensitive Special tariffs not perceived as

necessary Funding under EEC 2?


Residents’ survey

Prize Draw Technology ‘Blind’ Perception of heating and hot water Penwith HA, Westlea HA, SCHRI Not Clear Skies


Residents’ survey

Majority had positive views with notable exceptions

Controls understood Split between those who thought they were clear

and those who thought ‘could be clearer’

Costs Limited time with systems Average per week - £13 but ranged from £9 -£20 Majority thought very reasonable or affordable


Types of heat pump

Ground to water Ground to air Water to water Water to air Air to water Air to air


Types of operationHeat Source Heat Transfer Heat Output

Water

Closed Loop

Wet Radiator

Ground Open Loop Underfloor

Air Direct Exchange (DX) Warm air

Hot Water


Types of system

Ground (or water) source heat pump systems using closed loop water source heat pumps.

Ground (or water) source heat pump systems using open loop water source heat pumps.

Ground source heat pump systems using DX heat pumps.

Air source heat pump systems


Case studies

1 Penwith Housing Association, Ludgvan2 Westlea Housing Association, Withy Close 3 Fife Special Housing Association, Ochil View,4 Shettleston Housing Association, Glenalmond

Street, Shettleston5 Geothermal Heating and Cooling, Burton On Trent6 Geothermal Heating and Cooling, Kidderminster7 West Lothian Council


Key lessons

Costs dependent on local geological/site conditions Ground water levels Need for lining of boreholes

Bore both supply and return boreholes at the same time and an early stage in the project to monitor flows

Lack of a user manual


Key lessons

Need to explain to occupants that their radiators will not be hot to touch

Correct programming and setting of heat pump temperatures to ensure efficient running of the system is vital

Ensure that the best electricity tariff is used

Need to train maintenance contractors


The solution for hard-to-treat homes?

High specific heat loss (> 100 W/m2) so require relatively large heating systems.

If the CoP is >3, they will provide cheaper fuel running costs than any other type of heating system (at current tariff levels).

The issue is whether the capital cost is cost-effective compared to the alternatives: The capital cost of ground source heat pump systems is

relatively proportional to the output required.


The solution?

Running costs of heat pumps may be lower but not low enough for as an alternative to improved insulation.

Low maintenance costs: £120-£250 per year saving (compared with gas systems?)


Factors

Access to mains gas. Whether the property can be

reasonably well insulated using cost effective insulation measures such as cavity wall insulation and loft insulation.

Whether the property is to be comprehensively refurbished, including internal or external wall insulation and floor replacement.


Factors

The existing heating system in the property.

Sufficient space for the installation and adequate means of access for the installation equipment.

Other local factors that could affect the cost, e.g. ground water levels, the capacity of the local electricity network.


The MatrixHouse/Bungalow Flat Mid Rise Flat High Rise

Full Refurb Heating Only Full Refurb Heating Only Full Refurb Heating Only

Insuln

Poss

Insuln Not Poss

Insuln

Poss

Insuln Not Poss

Insuln

Poss

Insuln Not Poss

Insuln

Poss

Insuln Not Poss

Insuln

Poss

Insuln

Not Poss

Insuln

Poss

Insuln

Not Poss

Gas or Oil Central Heating Installed

No central heating but Mains Gas Available

No central heating Off Gas Network

Existing Electric Storage


Conclusions

Newbuild is the natural market A significant industry is developing Existing housing will require

individual assessment Not an alternative to insulation for

HTT, but complementary to it


Conclusions - suitability?

Ground source heat pumps for insulated houses off mains gas

Air source heat pumps for high rise/mid rise flats

Combination with small-scale renewables, e.g. wind/PV, but even higher capital costs


Insulating solid walls: a challenge for local

authorities and housing associations

Dave Barton, ImpetusAlastair Brooks, Impetus


Solid wall insulation research

Aims: To produce impartial, practical

and user-friendly reports To help policy community,

local authorities and housing associations


Objectives

To investigate: experience of specifying,

installation and ‘usage’; range of costs and perceived performance of the

technology.


Cost-effectivenessTypical energy saving

Typical cost benefit

[kWh/yr] [p/kWh]

4,800 0.16

3700 0.27

2735 0.49

5904 0.73

3400 0.98

3700 1.04

9000 2.42

3700 2.93

1750 9.29

500 13.33

750 18.67

36 23.15Heat recovery ventilation units

External wall insulation (50-70mm)

Solar water heating

Advanced glazing

Photovoltaic panels

Solid fuel cassettes

Oil condensing boilers

Internal wall insulation (50mm)

Ground Source Heat Pumps

Measure

Loft insulation (200mm)

Cavity wall insulation (50mm)

Gas condensing boiler


Why solid wall insulation?

More cost-effective than some measures currently promoted

Significant energy savings A body of experience in social housing Sound technical guidance Need to disseminate existing practice

and instil confidence


Methodology Desktop research Telephone interviews with key players Focus group of experience in:

social housing and promoting to the private sector

Identify case studies Householders’ feedback


General findings Building improvement measure, not

purely thermal improvements, particularly for EWI

Opportunity measure, needs long-term planning: not simple retrofit

Considerable associated costs and disruption

Technical detailing and quality installations are essential


Comparison of IWI and EWI

More experience on EWI EWI adds value EWI extends building life EWI better able to deal with cold

bridging EWI: systems approach, installers and

warranty Overall comparison table in report


Costs

Variable dependent upon building type, numbers etc

£2000 for IWI is not unusual Typically EWI £5000 to £10000 for

EWI Up to £25,000 for a new brick skin

and cavity wall


Findings: social housing

Generally good feedback from tenants on EWI

Issues with mixed tenure on blocks Integrate EWI with glazing programme IWI dependent upon skilled builders Some concern about robustness of dry-

lining in social housing No detailed research found on

householders feedback


Findings:private sector

A few small-scale schemes Limited take-up Grants of £1000 to £3000, some

interest free loans Usually marketed with other

measures


Social housing exemplars

Mid-Suffolk District council: post-1919 terrace improvements

London Borough of Enfield: improvements to high-rise blocks

Sandwell Borough Council: an example of a new brick skin and cavity wall

Sheffield City Council: non-traditional low-rise housing


Private housing scheme exemplars

Leicester City Council: Realise The Oxford Solar Initiative Stroud District Council’s Energy

Efficiency Grants Wyre Borough Council: Wyred for

Energy


Publications

Energy Efficiency Partnership for homes www.est.org.uk/partnership/

Hard-to-treat homes: a guide for local authorities Investigation of local authority activities w.r.t. HTTH Installing solid wall insulation: a challenge for local

authorities and housing associations Installing solid wall insulation: a challenge for policy

makers and scheme managers A guide to using heat pumps Heat pump study report Fuel poverty and non-traditional constructions


Thank you!

Documents

Hard-to-treat homes 11 May 2005 Tackling Hard-to-treat homes Heat pumps, solid wall insulation and non-traditional construction