Edmonton Net Zero Deep Energy Retrofit

Edmund Aunger completed a deep energy retrofit of his 1979 raised bungalow that made it net-zero.

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Building photo:

Edmonton, Alberta

Edmund Aunger followed these steps to complete this site-built deep retrofit:

  1. Gut the existing house, salvaging and selling most of the materials on Kijiji.
  2. Permanently remove the gas line.
  3. Cut off the roof overhangs and add OSB to fill the resulting holes.
  4. Complete plumbing, electrical, HVAC rough-ins as far as needed.
  5. Install the primary air barrier by wrapping the exterior of the house with Tyvek weather resistant barrier (WRB). Seal seams by overlapping the WRB with a continuous bead of acoustical sealant in between.  Secure the seams with strips of OSB so they don't pull apart over time.  Seal around all penetrations with acoustical sealant or Siga tape.
  6. Add exterior framing to make room for exterior insulation. Use 2x6 horizontal framing and 2x4 vertical framing on the walls. Use 2x12 horizontal framing and 2x6 vertical framing on the roof.
  7. Install new triple pane, fiberglass framed, high-efficiency windows and doors and south-facing windows built to maximize solar gains.
  8. Fill new wall and roof cavities with mineral wool insulation.
  9. Install Tyvek weather resistant barrier.
  10. Install rainscreen framing using vertical 1x4 vertical strips and 1x4 horizontal strips to accommodate vertical siding.
  11. Install siding and roofing.
  12. Insulate interior cavities with mineral wool.
  13. Cover basement floors and walls with 1" rigid insulation with 1/4" gaps at the seams, and spray foam into the gaps to seal the seams.
  14. Frame basement interior walls on top of the rigid insulation.
  15. Seal wall penetration with acoustical sealant with backing or Siga tape.
  16. Install vapour barrier/secondary air barrier (6 mil poly).  Be very careful that this is fully sealed.
  17. Finish the interior of the house taking care not to make holes through the vapour/air barrier.  All screws going through the drywall must hit framing behind the poly.
  18. Install solar panels. 

Other information:

  • Install recirculating kitchen hood fan with no duct to the outside.
  • Replace all lighting with LED.
  • Replace all existing appliances with the high-efficiency electric appliances, including a heat-pump, condensing clothes dryer, and washer with a super-fast spinning cycle so clothes are nearly dry after wash.
  • Replace old toilets with new low-flush toilets and install low-flow shower heads with pressure control valves.

BEFORE

AFteR

ENERGY 
CONSUMPTION
BEFORE
127
GJ/year
AFTER
0
GJ/year
COMFORT
BEFORE
Very cold (especially the basement) in the winter. Very dry air in the winter.
AFTER
Warm in the winter with a comfortable level of humidity.
BUILDING CONDITION
BEFORE
The house had not been maintained and was in disrepair. The following items needed to be replaced: roof, windows, doors, siding. No insulation on many of the basement walls. Old, inefficient furnaces. Severe ice damming in the winter. Old, worn interior finishes and appliances.
AFTER
Brand new condition.
RENEWABLES
BEFORE
none
AFTER
10.26kW Photovoltaic System
WAll Insulation
BEFORE
2x6 fiberglass R22
AFTER
2x6 + 2x6 + 2x4 mineral wood insulation R60
Ceiling Insulation
BEFORE
~6" cellulose R22.8
AFTER
6" cellulose + 2x12 + 2x6 mineral wool R88.8
Foundation Insulation
BEFORE
2x4 fiberglass R12 Many bare concrete foundation walls R0
AFTER
1"+ 3.5" + 2x4 rigid foam and mineral wool insulation R33
Windows
BEFORE
single pane, aluminum framed, slider
AFTER
triple pane, fibreglass framed, tilt-n-turn, South facing windows built to maximize solar gains
Ventilation
BEFORE
bathroom fans exhausted to the outside, hood fan vented to the outside, dryer vented to the outside, fresh air intake duct to the mechanical room
AFTER
HRV (Heat Recovery Ventilator)
Heating
BEFORE
two low efficiency gas furnaces
AFTER
heat pump with electric backup
Cooling
BEFORE
none
AFTER
heat pump can be used for air conditioning
Hot Water
BEFORE
medium efficiency gas hot water tank
AFTER
heat pump hot water tank, drain water heat recovery
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