Project Description
Pre-retrofit, this home in the Woodbine neighbourhood of Calgary, Alberta, used an estimated 81 per cent more energy than a typical house. Solar Homes Inc. worked with the owners to design a retrofit to make the home net-zero. By increasing the home’s airtightness, adding more insulation to the exterior walls and attic, and upgrading windows and mechanical system, the home’s energy needs dropped from 203 GJ a year to just 53. After installing 14.0 KW of Solar, the home is now net-zero.
Before & After
General
|
|
Before |
After |
Building Condition
|
Before
Standard for age. Older cladding. Some rot in exterior wall. 4.41 air changes an hour. |
After
Brand new exterior, including Hardie Siding. Improved air tightness to 1.47 air changes an hour. |
Comfort
|
Before
As expected – drafty, inconsistent temperatures. |
After
Fresher, cleaner air. Consistent Temperatures. |
Envelope
|
|
Before |
After |
Ceiling/Attic Insulation
|
Before
R30 |
After
R60 |
Foundation Insulation
|
Before
R10 |
After
R20 Insulation added to the foundation exterior after hydrovacing to the footings |
Wall Insulation
|
Before
R10 |
After
6-inch Roxul installed on the exterior of the house, adding another R24 to the original R10. Total – R34. |
Windows and Doors
|
Before
Various. R0.7 to R2.6. |
After
High-efficiency windows. R2.3 to R3.7. |
Air Changes per Hour
|
Before
4.41 ACH50 |
After
1.47 ACH50 |
Mechanical & Electrical
|
|
Before |
After |
Heating
|
Before
Natural Gas |
After
Electric Furnace (7.5 kW/26,000 BTU/h) Air-source heat pump (7 kW/24,500 BTU/h) |
Cooling
|
Before
None |
After
Air-source heat pump |
Hot Water
|
Before
40 Gallon natural gas hot water tank |
After
50 Gallon Rheen Heatpump hotwater |
Ventilation
|
Before
None |
After
Heat Recovery Ventilator |
Renewables
|
Before
None |
After
14.0 KW Solar |
Annual Energy Usage
|
|
Before |
After |
Total Net Consumption (with Renewables)
|
Before
203 GJ |
After
0 GJ |
Total Annual Consumption
|
Before
203 GJ |
After
51 GJ |
