Deep Energy Retrofits Building Enclosures—Part 1 Whole House; (Above Grade) Rob Dumont

Case Study Deep Energy Retrofit Double-Wall Double Roof Retrofit  Location: Saskatoon, Canada  Latitude 52 N  Annual Heating Degree Days: Fahrenheit  1968 Bungalow

Pre-Retrofit

Post Retrofit

Pre-Retrofit

Energy Results  Peak Heat Loss reduced from 13.1 kW to 5.5 kW

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

Step 2. Add second roof

Step 3. Add exterior wall system

Step 4. Finish details around windows & doors

Insulation of walls & bsmt walls

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

Post Retrofit—Asphalt Shingles, Stucco Walls

Comparison of Pre and Post Pre-Retrofit Post- Retrofit RatioPost/Pre Attic Insulation R20 RSI 3.5 R63 RSI Wall Insulation (Nominal) R 7 RSI 1.2 R 47 RSI Bsmt Floor Insulation R 0 No change ; Later R20 was added WindowsR2R31.5 Air Tightness 2.95 Pa 0.29 Pa 0.10

Advantages of Deep Exterior Envelope Retrofits  1. Conduction losses greatly reduced  2. Air leakage great reduced  3. Heating system can be greatly simplified.  4. Works best when simultaneous need for upgraded siding and roofingn  5. No interior space loss  6. House can be occupied during work.

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