Deep Energy RetrofitsDeep Energy RetrofitsBuilding Enclosures—Part 1Building Enclosures—Part 1Whole House; (Above Grade)Whole House; (Above Grade)

Rob DumontRob Dumont

robdumont@hotmail.com

Case StudyCase StudyDeep Energy RetrofitDeep Energy RetrofitDouble-Wall Double Roof Double-Wall Double Roof RetrofitRetrofit

Location: Saskatoon, Canada Location: Saskatoon, Canada Latitude 52 NLatitude 52 N Annual Heating Degree Days: 10950 Annual Heating Degree Days: 10950

Fahrenheit Fahrenheit 1968 Bungalow 1968 Bungalow

Pre-RetrofitPre-Retrofit

Post RetrofitPost Retrofit

Pre-RetrofitPre-Retrofit

Energy ResultsEnergy Results

Peak Heat Loss reduced from 13.1 kW to Peak Heat Loss reduced from 13.1 kW to 5.5 kW5.5 kW

Step 1. Cut off eaves and Step 1. Cut off eaves and wrap roof and walls with wrap roof and walls with polypoly

Step 2. Add second roofStep 2. Add second roof

Step 3. Add exterior wall Step 3. Add exterior wall systemsystem

Step 4. Finish details Step 4. Finish details around windows & doorsaround windows & doors

Insulation of walls & Insulation of walls & bsmt wallsbsmt walls

R40 on Roof ; R40 on R40 on Roof ; R40 on Walls; R40 in Bsmt WallsWalls; R40 in Bsmt Walls

Post Retrofit—Asphalt Post Retrofit—Asphalt Shingles, Stucco WallsShingles, Stucco Walls

Comparison of Pre and PostComparison of Pre and Post

Pre-RetrofitPre-Retrofit Post-Post-RetrofitRetrofit

RatioRatio

Post/PrePost/PreAttic InsulationAttic Insulation R20R20

RSI 3.5RSI 3.5

R63R63

RSI 12.5RSI 12.5

3.63.6

Wall InsulationWall Insulation

(Nominal)(Nominal)

R 7R 7

RSI 1.2RSI 1.2

R 47R 47

RSI 8.3RSI 8.3

4.34.3

Bsmt Floor Bsmt Floor InsulationInsulation

R 0R 0 No change ;No change ;

Later R20 was Later R20 was addedadded

WindowsWindows R2R2 R3R3 1.51.5

Air TightnessAir Tightness 2.95 ac/h @50 2.95 ac/h @50 PaPa

0.29 ac/h0.29 ac/h

@50 Pa@50 Pa

0.100.10

Advantages of Deep Advantages of Deep Exterior Envelope Exterior Envelope RetrofitsRetrofits

1. Conduction losses greatly reduced1. Conduction losses greatly reduced 2. Air leakage great reduced2. Air leakage great reduced 3. Heating system can be greatly 3. Heating system can be greatly

simplified.simplified. 4. Works best when simultaneous need for 4. Works best when simultaneous need for

upgraded siding and roofingnupgraded siding and roofingn 5. No interior space loss5. No interior space loss 6. House can be occupied during work.6. House can be occupied during work.

DisadvantageDisadvantage

Attic upgrades are usually much less Attic upgrades are usually much less expensive than a double roof retrofit, but expensive than a double roof retrofit, but in some cases the attic is non-existent or in some cases the attic is non-existent or inaccessible.inaccessible.