Rutherford Cottage, built by Alberta's first premier in 1908, received a deep retrofit in 2023 that preserved its historic charm while bringing the building up to net-zero standards.
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Banff, Alberta
The Rutherford Cottage, built in 1908 for Alberta’s first premier, Alexander Rutherford, underwent a remarkable transformation in 2023 thanks to the Bowstrings Heritage Foundation and the organisation’s commitment to preserving the building’s heritage while making it energy efficient. Joel Piecowye and the team at Shugarman Architecture + Design designed a modern addition to complement the original structure. With the help of Peter Amerongen from Retrofit Canada, they devised a plan to make the cottage net zero while maintaining its historical integrity. The retrofit included the following:
Refitted and resealed original windows with new putty and weather stripping.
Installed new double-glazed storm windows for added performance.
Installed new windows on the main and second floors.
Painted and restored original cedar siding to preserve historical integrity.
Located new air tightness control layer on the inside due to crumbling lath and plaster walls, and to preserve the original aesthetic.
Increased wall thickness, filled cavity with dense-packed cellulose, and added air/vapour barrier to boost insulation to R25.
Stabilized dug-out foundation with new insulated retaining walls and floor slab.
Insulated original foundation and exposed earth with 6” low-environmental-impact foam.
The cottage now meets the CHBA Net Zero standard for new homes gets all of its heat from air-source heat pumps.
The gasline was disconnected in winter 2023.
Insulating the interior walls
Inside, main floor exterior wall strapped with horizontal 2x4s, ready for insulation.
Second story, inside exterior wall strapped, blowing mesh installed to hold blow-in cellulose insulation.
Before & After
BEFORE
AFTER
ENERGY CONSUMPTION
BEFORE
250.3
GJ/year
AFTER
39
GJ/year
COMFORT
BEFORE
Drafty, inconsistent temperatures. 10 ACH50 or worse
R24 eff- 2x4 16" OC framing with 2x4 2x4" horizontal straping with R15 Roxul Comfortbattin both cavities
Ceiling Insulation
BEFORE
Sloped Ceiling ~ R8
AFTER
R24 eff- 2x4 16" OC framing with 2x4 2x4" horizontal straping with dense packed cellulose in both cavities
Foundation Insulation
BEFORE
Slab: None. Foundation: None.
AFTER
Slab: R6- 2 layers of 2" EPS. Foundation: ~R22 4" of low GWP spray foam.
Windows
BEFORE
Single glazed wood with a few storm windows
AFTER
Orginal single glazed inner window restored with the new dual glazed LowE argon filled storm windows , both air sealed with advanced weatherstripping system.
Ventilation
BEFORE
None
AFTER
vänEE G2400H ECM ERV
Heating
BEFORE
Induced Draft ~80% efficient
AFTER
Daikin Skyair: Outdoor Unit RZQ36TAVJUA Airsource Heat Pump, Indoor Unit FTQ36TAVJUD Air Handler
Cooling
BEFORE
None
AFTER
Per Above
Hot Water
BEFORE
Old gas hotwater tank ~55% efficient
AFTER
Rheem 80-Gallon hybrid air source heat pump hot water tank
