Passive!House!Cer-ﬁcaon!in! ScandinaviaPassive!House!Cer-ﬁcaon!in! Scandinavia! Rolf!Jacobson,!LEED!AP!! ZEB,!Norwegian!University!of!!!!!Science!and!Technology! CSBR,!University!of!Minnesota

Passive House Cer-fica-on in

Scandinavia

Rolf Jacobson, LEED AP

ZEB, Norwegian University of Science and Technology CSBR, University of Minnesota [email protected] October 17, 2013

Lærkehaven, in Lystrup Denmark -‐ 32 PHI-‐cer-fied apartments

Outline

1.  Research background 2.  Scandinavian climate 3. Model Passive House performance 4.  Overview: status of PH cer-fica-on in Scandinavia 5.  Detailed: cer-fica-on requirements 6.  Cer-fica-on trends and implica-ons for North America

Passive House Cer-fica-on in Scandinavia October 17, 2013

Research background •  B.A. in physics and math from St. Olaf College, 2001 •  Worked as a framer building homes from 2002 -‐ 2005 •  Began work on Master’s thesis in 2007, U of M •  Fulbright scholarship to complete thesis and study cold climate envelopes in Norway in 2010/2011, NTNU •  Currently -‐ energy modeling and envelope design consultant (PHPP, REMRate, WUFI, THERM)


Background •  In Norway, studied at the Center for Zero Emissions Buildings (ZEB) •  Housed within the Norwegian technical university, NTNU, in Trondheim, and associated with na-onal research group SINTEF •  Thesis focused on passive house envelopes in cold climates -‐ construc-on types and details, thermal bridging, hygrothermal performance, life-‐cycle environmental impacts •  Twice abended Scandinavian Passivhus conference (Passivhus Norden), toured new building projects in Norway and Denmark, learned about Scandinavian residen-al building techniques and regula-ons including “Passivhus” Passive House Cer-fica-on in Scandinavia October 17, 2013

Scandinavian Climate

Hea-ng degree day (HDD 65°F) map of Europe.

12600 10800 9000 7200 5400 3600 1800 0 (°F)

(Image from European Reanalysis and Observa-ons for Monitoring)

Denmark – similar to Germany Sweden and Norway – most areas substan-ally colder



Hea-ng degree day (HDD 65°F) map of Europe.

12600 10800 9000 7200 5400 3600 1800 0 (°F)

(Image from European Reanalysis and Observa-ons for Monitoring)

La-tude – most of Europe is north of the con-nental U.S.

La-tude 45°N Minneapolis, MN


Arc-c circle



Model Passive House Performance

footprint: 24’ x 36’ 2,240 sf floor area walkout basement, loj

• R-‐60 above grade walls

• R-‐50 below grade walls • R-‐80 roof

• R-‐60 floor slab

• Op-win windows: U-‐0.15, SHGC 0.52

• assumed air-ghtness: 6 ACH@50Pa

south eleva-on

west eleva-on north eleva-on

east eleva-on

Model Passive house used in PHPP to inves-gate climate effects



Denver, Chicago, Copenhagen similar with 6000 HDD Minneapolis more similar to Scandinavian ci-es with roughly 8000 HDD



Model house easily meets 15 kWh/m2/yr requirement in Denver, Chicago, just passes in Minneapolis. Model house fails in all Scandinavian ci-es except Copenhagen.

CONCLUSION – R60 walls and slab, R80 roof not adequate in Norway and Sweden



Midwestern ci-es have 2x more winter radia-on on average than Scandinavian ci-es and Denver has close to 3x as much.



Solar savings frac-on averages 55% in Midwestern ci-es (not including Denver at 70%), only 40% in Scandinavian ci-es.


Model Passive House Performance To achieve a specific space heat demand of 15kWh/m2/yr or less in the Oslo climate requires the model house built with: •  R100 above grade walls •  R80 below grade walls •  R140 roof •  R80 floor slab

And Oslo is not the most challenging Scandinavian climate!


Exis-ng energy codes – Norway, Denmark, Sweden

Status of PH cer-fica-on in Scandinavia

Chart from Promo-on of European Passive Houses, “Passive House Solu-ons”, May 2006


Status of PH cer-fica-on in Scandinavia Sweden •  Forum for Energy Efficient Buildings (FEBY) – publicly funded research group developed their own “passivhus” standard in 2007, now FEBY ’12 •  IG Passivhus Sverige – separate nonprofit promo-ng PHI standard •  Neither has been officially adopted by the state •  Surpassed 2000 living units cer-fied to FEBY standard


Status of PH cer-fica-on in Scandinavia Norway •  NS3700 adopted as na-onal standard for “Passivhus” construc-on in 2010

•  Adopted by the state with the express wriben intent of encouraging low-‐energy and passivhus construc-on

•  # of units – wai-ng for response, cer-fied to NS3700 standard


Status of PH cer-fica-on in Scandinavia Denmark

•  Most projects follow PHI standard

•  Cer-fica-ons awarded through Danish PHI affiliate, Dansk Passivhus Forum (DPHF), danskpassivhusforum.dk

•  Approaching 300 living units, plus notable large commercial/ins-tu-onal projects, cer-fied to PHI standard


Cer-fica-on in Sweden – FEBY’12 Cer$fica$on Requirements Denmark -‐ PHI Sweden -‐ FEBY'12 Sweden -‐ Notes Specific Space Heat Demand

</= 15 kWh/m2/yr no requirements set

Specific Space Cooling Demand

</= 15 kWh/m2/yr + 0.3 W/m2/yrK x CDD no requirements set

Air$ghtness Test </= 0.6 ACH@50Pa </= 0.3 l/s/m2 envelope area @ 50Pa (0.06

cfm/sf envelope area) (or) </= 0.5 l/s/m2 floor area @ 50Pa for small houses (0.72 ACH @50Pa)

First result is roughly equivalent to 0.6 ACH for small homes, but much lower as building size increases.

Specific Primary Energy Demand

</= 120 kWh/m2/yr </= 63, 59, 55 kWh/m2/yr in Climate zone 1,2,3 respec-vely (no electric heat) </= 31, 29, 27 kWh/m2/yr in Climate zone 1,2,3 respec-vely (electric heat) </= 78, 73, 68 kWh/m2/yr in Climate zone 1,2,3 respec-vely (district+mixed energy) (district + mixed energy calculated using 2.5*Eel + 0.8*Eheat + 0.4*Ecool + Eother

Requirements listed for buildings less than 400m2, otherwise subtract 5 kWh/m2/yr for no electric heat, 2 kWh/m2/yr for electric heat, and 5kWh/m2/yr for district heat. For non-‐district heat op-ons, this is delivered energy, not primary energy, and only includes energy used for hea-ng, hot water, and ven-la-on. For district + mixed heat, listed energy demand is primary energy

Hea$ng Load </= 10 W/m2 (alterna-ve to specific space

heat demand requirement) </= 19 w/m2 in Climate zone 1 </= 18 W/m2 in Climate zone 2 </= 17 W/m2 in Climate zone 3 2W/m2 subtracted for floor area > 400m2

Requirements listed for buildings less than 400m2, otherwise subtract 2 W/m2/yr. Alterna-vely, can use equa-on Max VFT = 12.3 -‐ 0.227 x DVUT12 day

Cooling Load </= 10 W/m2 + etc (alterna-ve to specific

space cooling demand req.) no requirements set


Cer-fica-on in Sweden – FEBY’12

•  Country divided into 3 climate zones

•  Hea-ng load and specific primary energy requirements are variable depending on climate zone

•  Alterna-vely, equa-ons can be used to calculate exact hea-ng load and energy requirements for a given municipality (rarely used) •  Zone 1 is the primary compe--on zone between FEBY and PHI








First result is roughly equivalent to 0.6 ACH for small homes, but much lower as building size increases. Qualify for 0.5 l/s/m2 if form factor > 1.7. (Form factor = envelope area/floor area)









model house form factor = 1.9, requirement is approx. 0.7 ACH@50Pa











Requirements listed for buildings less than 400m2, otherwise subtract 5 kWh/m2/yr for no electric heat, 2 kWh/m2/yr for electric heat, and 5kWh/m2/yr for district heat. For non-‐district heat op-ons, this is delivered energy, not primary energy, and only includes energy used for hea$ng, hot water, and ven$la$on. For district + mixed heat, listed energy demand is primary energy






Removes plug loads from considera-on, occupant behavior is separated from building design

















If standard were applied in Minneapolis: Requirement = 17 W/m2 Model house performs at: 17.0 W/m2


Cer-fica-on in Sweden – FEBY’12 Component performance Denmark Sweden Frequency of Overhea$ng

</= 10%, T>25C (77F) </= 10%, T>26C (79F) this is a recommenda-on

Thermal Bridges ψ </= 0.01 W/mK, calculated using

exterior dimensions thermal bridge heat loss included in hea-ng load calcula-on, no specific reqs.

Mechanical Ven$la$on

Heat recovery efficiency >/= 75%, fan efficiency >/= 0.45Wh/m3

heat recovery efficiency >/= 70% this is a recommenda-on

Envelope Components

windows </= U-‐0.14 average window U-‐value </= U-‐0.14 (calculated on an area-‐weighted basis)


Cer-fica-on in Sweden – FEBY’12 Calcula$on Methodology Denmark Sweden

Internal Heat Sources

2.1 W/m2 (equipment + people, standard dwelling)

1.13 kWh/ person/ day 30 kWh/m2 floor area for equipment (yearly? hea-ng season?)

Ven$la$on Air Flow Rates

0.3 ACH (volume by TFA * 2.5m) >/= 0.35 l/s/m2 (0.5 ACH, volume calculated using gross floor area * 2.5)

This ven-la-on rate is set by the building regula-ons, not FEBY

Occupancy Rates 35 m2/person (range of 20 -‐ 50m2) According to Sveby, based on floor area Energy Calcula$on Protocol

PHPP EN ISO 13790

Floor Area Calcu-‐ la$on Protocol

German Floor Area Ordinance "TFA" Set by BBR, "Atemp" = gross area minus exterior wall thickness and empty shajs

Envelope Area Calc. Protocol

exterior dimensions interior dimensions


Cer-fica-on in Sweden – FEBY‘12 Summary of major changes •  Concentra-ng on hea-ng load requirements (rather than specific space heat demand) largely removes impact of solar gain (large south window areas less abrac-ve to designers)

•  Energy and hea-ng load requirements become a func-on of climate zone (requirements relaxed for colder climates)

•  Energy and hea-ng load requirements also vary depending on floor area (requirements -ghtened for larger buildings)

•  Air leakage becomes a func-on of envelope area – makes much more sense especially for large buildings where 0.6 ACH @50Pa could result in dangerously leaky envelopes

•  Energy use requirements disassociate expected occupant behavior from building design

•  If standard is applied in Minneapolis climate, model house -‐ R60 walls above grade, R-‐50 below grade, R80 roof, R60 floor slab – just barely passes hea-ng load requirement

•  If standard is applied in Stockholm climate, model house just barely passes hea-ng load requirement (failed to meet PHI standard)

•  Verified Performance -‐ “Cer-fikat” awarded during planning stages, “Verifikat” awarded ajer 2 years of energy reports showing successful opera-ons


Cer-fica-on in Norway – NS3700 Cer$fica$on Requirements Denmark -‐ PHI Norway -‐ NS3700 Norway -‐ Notes Specific Space Heat Demand

</= 15 kWh/m2/yr </= 15 kWh/m2/yr for θym >/= 6.3C </= 15 + 2.1*(6.3 -‐ θym) for θym < 6.3C </= 15 + 5.4*(250 -‐ BRA)/100 for θym >/= 6.3C </= 15 + 5.4*(250 -‐ BRA)/100 + (2.1 + 0.59*(250-‐BRA)/100)*(6.2 -‐ θym)

for θym < 6.3C

θym = average yearly temperature BRA = gross heated floor area first two results for BRA >/= 250m2, second two results for BRA < 250m2


</= 15 kWh/m2/yr + 0.3 W/m2/yrK * CDD no mechanical cooling allowed

Air$ghtness Test </= 0.6 ACH@50Pa </= 0.6 ACH@50Pa


</= 120 kWh/m2/yr Delivered Energy < Total Energy demand -‐ 50% DHW energy demand

Delivered energy includes kWh of electricity plus kWh value of delivered fossil fuels

Hea$ng Load </= 10 W/m2 (alterna-ve to

specific space heat demand requirement)

</= 0.6 W/m2/K for BRA < 100m2 </= 0.55 W/m2/K for BRA 100 -‐ 250m2 </= 0.5 W/m2/K for BRA >/= 250m2

Varies by winter temperature and home size. The temperature difference used in the heat load calcula-on is the difference between interior setpoint and the coldest month's average temperature

Cooling Load </= 10 W/m2 + etc (alterna-ve to

specific space cooling demand req.)

no mechanical cooling allowed




for θym < 6.3C















In Minneapolis, θym = 7.2C, If standard were applied in Minneapolis: requirement = 17.3 kWh/m2, model house performance = 12.9 kWh/m2




for θym < 6.3C















Prac-cally speaking, this requirement forces use of heat pump or solar power




for θym < 6.3C















If standard were applied in Minneapolis: requirement = 17.2 W/m2 model house performance = 17.0 W/m2


Cer-fica-on in Norway – NS3700 Component performance Denmark Norway

Frequency of Overhea$ng

</= 10%, T>25C (77F) NA

Thermal Bridges ψ </= 0.01 W/mK, calculated using exterior dimensions

ψ </= 0.03 W/m2K (normalized by BRA and calculated using interior dim.)

Mechanical Ven$la$on

Heat recovery efficiency >/= 75%, fan efficiency >/= 0.45Wh/m3

Heat recovery efficiency >/= 80%, fan efficiency >/= 0.417 Wh/m3

Envelope Components

windows </= U-‐0.14 exterior wall >/= R-‐38, roof >/= R-‐44, floor >/= R38, windows/door </= U-‐0.14

Envelope components must meet these mandatory minimum R-‐values regardless of climate or building size


Cer-fica-on in Norway – NS3700 Calcula$on Methodology Denmark Norway Internal Heat Sources

2.1 W/m2 (equipment + people, standard dwelling)

1.95 W/m2 for ligh-ng 1.8 W/m2 for equipment 1.5 W/m2 for people

REM Rate uses roughly 4.1 W/m2

Ven$la$on Air Flow Rates

0.3 ACH (volume by TFA * 2.5m) >/= 0.48 ACH for dwellings >/= 110m2 and increasing linearly to 0.64 ACH for smallest units

(volume calculated using BRA * 2.5m)

Occupancy Rates 35 m2/person (range of 20 -‐ 50m2) ? Energy Calcula$on Protocol

PHPP NS 3031

Floor Area Calcu-‐ la$on Protocol

German Floor Area Ordinance "TFA"

NS 3940, "BRA" = gross area minus exterior wall thickness and empty shajs

Envelope Area Calc. Protocol

exterior dimensions NS 3940, interior dimensions


Cer-fica-on in Norway – NS3700 Summary of major changes •  Hea-ng load requirement is more demanding than specific space heat demand – encourages smaller glazing areas

•  Energy and hea-ng load requirements become a func-on of climate zone (requirements relaxed for colder climates)

•  Energy and hea-ng load requirements also vary depending on floor area (requirements -ghtened for larger buildings)

•  Delivered energy requirement moves in direc-on of requiring some renewable energy on site

•  Prescrip-ve approach introduced to set minimum envelope performance

•  If standard is applied in Minneapolis climate, model house -‐ R60 walls above grade, R-‐50 below grade, R80 roof, R60 floor slab -‐ easily passes specific space heat demand and narrowly passes hea-ng load.

•  If standard is applied in Oslo climate, model house narrowly fails to meet specific space heat demand and flunks hea-ng load.


Summary – required envelope performance

•  Denmark: Climate -‐ similar to Germany Passive House standard – retained original PHI defini-on and model

Model house -‐ R50 walls, R60 floor slab, and R80 roof in Copenhagen

•  Sweden: Climate -‐ substan-ally more challenging Passive House standard -‐ FEBY’12 relaxed compared to PHI defini-on

Model house -‐ R60 walls, R60 floor slab, and R80 roof in Stockholm

•  Norway: Climate -‐ substan-ally more challenging Passive House standard – NS 3700 slightly relaxed compared to PHI

Model house -‐ unclear what envelope R-‐values are required in Oslo climate due to differences in heat load calcula-on and allowable internal gains, but likely higher than FEBY’12

Trondheim example – R63 walls, R71 floor slab, R87 roof (and that is for a mul--‐family row-‐house in less challenging climate than Oslo)


Implica-ons in Cold North American Climates •  Climate Issue: Climate zones 5, 6, 7 compare well to Scandinavia in terms of HDD, but Midwestern regions offer 2x the available solar insola-on. Result – easier to meet PHI standard when substan-al south-‐facing glazing is used.

•  Standard modifica-ons: In Scandinavia, passive house defini-ons were created that adjust for available solar gain (hea-ng load targets become primary focus, discouraging large glass areas). If same principle was applied in North America, what would that entail? Large glass areas reduce specific space heat demand but can create comfort issues (and anecdotal evidence suggests they do). But high solar insola-on is equally good for solar power: $6000 investment in 3 kW PV = 4000 kWh/yr = $440 of electricity ($0.11/kWh)

$6000 investment in 75sf Op-win windows = 1350 kWh = $76 of natural gas ($1.50/therm)


Implica-ons in Cold North American Climates •  Climate Issue: Extreme cold temperatures in both Scandinavia and North America result in heat loads that cannot be met using ven-la-on air alone.

•  Standard modifica-ons: Since hea-ng loads cannot be met with ven-la-on air, a supplemental hea-ng system is s-ll required. There is no “tunnel through the cost barrier”, and the cheapest current op-on for both Scandinavian and North American passive houses is to use supplemental electric resistance heat. Scandinavian Passivhus defini-ons discourage electrically heated homes with -ghter energy requirements.


Implica-ons in Cold North American Climates •  Social norms: Home sizes are generally smaller in Scandinavia, but lack of buildable area requires careful planning and promo-on of high density construc-on. In North America, home sizes are much larger, and growing. Moreover, it is simply easier to meet PHI standard with larger buildings (generally less envelope surface area to floor area).

•  Standard modifica-ons: Scandinavian passivhus defini-ons discourage large homes with -ghter energy requirements. LEED and Energy Star already do this in the U.S.


Implica-ons in Cold North American Climates •  Construc-on norms: Scandinavian energy codes are already quite good, energy costs are high but not exorbitant, so lible incen-ve exists for either builders or home buyers to upgrade to Passive House level performance. Even less incen-ve exists in North America, and the learning curve and required improvement in performance is even steeper.

•  Standard modifica-ons: Scandinavian Passivhus standards were designed to move the construc-on industry forward incrementally, driving larger volume of construc-on, keeping costs lower, and encouraging adop-on with builders and home buyers. This has generally been a successful approach.

Sweden = 1800 units built in 6 years since adop-on of FEBY in 2007 Norway = Several hundred units built in 3 years since adop-on of NS3700 in 2010


Documents

Passive!House!Cer-ﬁcaon!in! ScandinaviaPassive!House!Cer-ﬁcaon!in! Scandinavia! Rolf!Jacobson,!LEED!AP!! ZEB,!Norwegian!University!of!!!!!Science!and!Technology! CSBR,!University!of!Minnesota