Project Description
Planning the Retrofit
To create more living space, the family decided to remove the existing roof and attic to build a second-story addition. The addition expanded the liveable floor area from 178 m² to 342.3 m².
Starting with the envelope, the retrofit team insulated and sealed the foundation right to the footings. They used a 8” layer of EPS insulation and sealed with a Solprema Colphene water proofing membrane. They chose a modified Larsen Truss assembly to add insulation to the above ground walls, and installed a generous layer of blown-in insulation to the new roof. The family opted to replace all windows and doors with high efficiency units, and the retrofit team tied in the air barrier to these new units to ensure a continuous seal. The new siding gave the envelope work a clean, refreshed finish.
The insulation and air sealing dramatically reduced the thermal loads of the home, which allowed the retrofit team to reduce the size of the heating equipment required. They replaced the condensing gas boiler with a minisplit heat pump—adding both heating efficiency and summer cooling. They also installed a 96%-efficient HRV for active ventilation.To accomodate the newly electrified equipment, the project included an electrical service upgrade from 100 amp to 200 amp.
Before & After
General
|
|
Before |
After |
Building Condition
|
Before
Exterior possibly updated in the late 1970’s or early 1980’s. |
After
Clean exterior finishes and modern charm really improve the curb appeal. |
Envelope
|
|
Before |
After |
Ceiling/Attic Insulation
|
Before
Several inches of blown in insulation in flat roof attic. Cathedral ceiling cavity filled with fiberglass batts (assumed) |
After
~16 inch rafter installed right on the existing roof. Filled full with dense packed cellulose insulation. |
Ceiling/Attic Insulation
|
Before
22.49 R |
After
76.49 R |
Foundation Insulation
|
Before
Typical 2×4 frost wall, Fiberglass paperback batts, header also insulated |
After
Added 8 inches of Type II EPS foam insulation to the exterior foundation wall (full height), header insulation increased as well |
Foundation Insulation
|
Before
7 R |
After
38 R |
Wall Insulation
|
Before
2×4 rough cut wood frame, 16 inch centers, updated fiberglass batts |
After
Original walls maintained, 10 inch Larsen Truss system, filled with dense packed cellulose insulation. |
Wall Insulation
|
Before
12.69 R |
After
45.44 R |
Windows and Doors
|
Before
A mix of recently updated windows and doors and others updated likely in the 1980’s |
After
Most of the windows are now wood frame, triple pane, low-e, and argon filled. There is one patio door that has wood cladding, is triple pane, low-e, and is argon filled. There are two fiberglass, medium density spray foam core doors. |
Air Changes per Hour
|
Before
6.16 ACH50 |
After
0.57 ACH50 |
Air Sealing
|
Before
No proactive air sealing beyond spray foam being added to some window frames. |
After
Continuous air and thermal barriers over original exterior sheathing of walls and roof. |
Mechanical & Electrical
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|
Before |
After |
Heating
|
Before
Condensing natural gas boiler (95% AFUE) |
After
Mini-split heat pump 52000 Btu (Heating COP 3.64), existing system still integrated |
Cooling
|
Before
None |
After
Mini-split heat pump 52000 Btu (Cooling COP 3.21) |
Hot Water
|
Before
Combo Boiler heating system (95% AFUE) with Electric Hot Water Heater 85L Capacity EF 0.92 |
After
Same as before |
Ventilation
|
Before
Naturally aspirated, no whole home system. |
After
Heat Recovery Ventilator (96% Efficiency) |
Electrical Service
|
Before
100 Amps |
After
200 Amps |
Annual Energy Usage
|
|
Before |
After |
Light and Appliance Energy Consumption
|
Before
11.43 GJ |
After
11.6 GJ |
Other electrical consumption
|
Before
13.97 GJ |
After
13.92 GJ |
Space Cooling
|
Before
0 GJ |
After
3.48 GJ |
Space Heating
|
Before
86.36 GJ |
After
11.6 GJ |
Ventilation Energy Use
|
Before
0 GJ |
After
1.16 GJ |
Water Heating
|
Before
15.24 GJ |
After
16.24 GJ |
Total Net Consumption (with Renewables)
|
Before
127 GJ |
After
58 GJ |
Total Annual Consumption
|
Before
127 GJ |
After
58 GJ |
Annual Cooling Demand Intensity
|
Before
0 kWh/m2/a |
After
2.82 kWh/m2/a |
Annual Electricity Consumption
|
Before
11944 kWh |
After
15556 kWh |
Annual Heating Demand Intensity
|
Before
134.77 kWh/m2/a |
After
9.41 kWh/m2/a |
Annual Natural Gas Consumption
|
Before
84 GJ |
After
1 GJ |
Energy Use Intensity
|
Before
198.19 kWh/m2/a |
After
47.07 kWh/m2/a |
Carbon Emissions
|
|
Before |
After |
Annual Operational Carbon Emissions – Electricity
|
Before
179.17 KgCO2e |
After
233.33 KgCO2e |
Annual Operational Carbon Emissions – Natural Gas
|
Before
4427.45 KgCO2e |
After
52.6 KgCO2e |
