Edmonton, Alberta is one of the biggest hubs of industry in the Prairie provinces, centring around its largest commodity - oil! In fact, the oil industry is so integral to the city's identity, that they named their beloved hockey team after it: The Edmonton Oilers!
But Edmonton is known for a lot more than just its oil and die-hard hockey fans. Edmonton has some of the highest daylight hours of any Canadian city, it also has enough festivals year-round to earn its nickname as “the Festival City” (my personal favourite is K-days!), and Edmonton has the highest number of Net Zero homes in Canada.
What is a Net Zero home? It's a dwelling that generates more renewable electricity than it uses annually, which not only saves the occupants the high costs of heating and cooling but serves our collective well-being by respecting the environment.
Behold Canada's first Net Zero residence - the Riverdale NetZero project - completed by Habitat Studio, and a response to the EQuilibrium Housing Initiative, a national challenge by the Canada Mortgage and Housing Corporation in 2007. The goal? To challenge Canadian builders and developers to be more environmentally aware in their conventional building practices. The initiative resulted in 12 projects across Canada and the completion of the Riverdale NetZero project.
The Riverdale NetZero project is a three-bedroom duplex, with each two-storey unit being about 234m2 (2510 square feet).
The Riverdale neighbourhood is just east of downtown, adjacent to the River Valley along the North Saskatchewan River, Canada’s largest urban park with over 150 km of trails, as well as connections to attractions such as the Edmonton Valley Zoo, Fort Edmonton Park, and the Muttart Conservatory. Very fitting that the pilot Net Zero project in Edmonton has such a strong connection to Edmonton’s most treasured park!
So how did the very first Net Zero house in Canada achieve success?
Consider this: An average house uses about six times more heating fuel energy than electricity. Therefore, the design team's biggest challenge was to ensure the dwelling stayed warm because, like most Canadian cities, Edmonton's winters are very, very cold. So in order to achieve net-zero energy usage, the Riverdale home incorporated passive solar heating techniques by maximizing the placement and exposure of all its windows, ensuring it had a sufficient concrete mass to absorb heat, as well as a super tight building envelope to mitigate heat loss through the walls and roof. A Heat Recovery Ventilator (HRV), in combination with heavy insulation and extra-thick windows, reduced the heating needs of the house to the equivalent of six hairdryers when it is -32 degrees celsius outside which helped reduced the heating load. As well, the heating unit of the project doesn’t use a natural gas line, so there are no emissions because it's heated through electricity!
For the cooling during the summer months, a combination of the highly insulated building envelope, concrete thermal mass, and HRV act to regulate temperatures without adding significant electrical loads to the project.
On top of dealing with the major issue of heating, high-efficiency appliances, and a solar panel electrical generation system work together to achieve net-zero energy usage. Recycled building materials such as glulam beams from an old liquor store, hardwood flooring from a school gymnasium, and recycled newspaper as insulation were used to further embody the ideas of environmental stewardship that were at the foundation of the EQuilibrium initiative. As a ground-breaking project, the design team allowed half of the duplex open for presentations and teaching on how Net Zero homes can be achieved. Quite wondrously, this led to the desired outcome as Net Zero homes are possible and more importantly, successful.
If you would like to read more regarding the legacy of the Riverdale NetZero project, check out this article about the award-winning Windsor Park Net-Zero project, also found in Edmonton!
Interested in sustainable design? Take a look at these other Houseporn articles!
All photos courtesy of Habitat Studio.
Researched and written by Matthew Mun, a student in the Masters of Architecture Program, Azrieli School of Architecture and Urbanism, Carleton University