Five builders in four provinces are constructing 26 homes as part of the largest net zero energy community project in Canada.
“We wanted to demonstrate that it’s feasible across Canada, so our objective was to find five production builders that have experience building green in their track process and take it one level further and go net zero,” said Candice Luck, director of strategy and programs for buildABILITY Corporation, a housing industry consulting firm that’s leading the project along with insulation and roofing products manufacturer Owens Corning Canada.
Owens Corning’s Net Zero Housing Community Project is part of the federal government’s ecoENERGY Innovation Initiative. Natural Resources Canada is contributing almost $2 million towards consultancy fees to help the five builders design the houses and create technical specifications they can use in the future.
Building science and technical consultant companies Ameresco Inc., Building Knowledge Canada Inc., MMM Group (formerly Enermodal Engineering Ltd.), HAWK-EYE Technical Services and SAIC Canada are also involved.
Projects in five cities
Construction Voyer is building a three-storey condominium with six units in Laval, Que. Minto Communities is constructing a single detached model home (shown in image) and a row of four townhouses in the Ottawa suburb of Kanata. Mattamy Homes Limited, Provident Development Inc. and Reid’s Heritage Homes are respectively building five single detached homes in Calgary, Halifax and Guelph, Ont. (shown in image under construction).
Project partners include: solar manufacturer Canadian Solar Inc.; window and door manufacturer JELD-WEN; electronics product manufacturer Mitsubishi Electric Sales Canada Inc.; and heating, cooling and water heating solutions company Rheem.
To date in Canada there have been few demonstrations of net zero energy housing on a community scale that are market-ready for production builders. It’s hoped the project will demonstrate affordable net zero energy housing is possible and act as a platform for the broader adoption of net zero energy housing across Canada.
The project is also meant to assess and resolve challenges related to site planning, construction, equipment, grid connections, cost, trade capability, warranties, reliability, sales, marketing, and homebuyer information and education.
Net zero housing elements
While the houses in each city will be different, they’ll share common elements to help them achieve net zero energy status. They include:
* walls and an envelope with rigid insulation and an exterior air barrier to make things airtight and prevent leakage of warm air in the winter and cooler air during the summer;
* triple-pane windows;
* a higher-than-normal amount of roof insulation;
* a heat recovery ventilator;
* an air source heat pump, which exchanges air between the outside and the inside of the house, as the main heating component instead of a furnace;
* a hybrid heat pump water heater that uses the air source heat pump to heat the house’s water;
* and power generated by electricity supplied through solar photovoltaic panels on the roof, which will also allow homeowners to connect to the electricity grid and offset electricity consumption.
The builders are funding all of the materials and construction costs and aren’t permitted to make a profit on the net zero portion of the houses, but can make their margins on other parts of the residences.
“They’re budget-conscious and they need to build it in a fashion that they can sell it,” said Luck. “They’re very, very careful about what technologies they can include and the consultants that are working with the builders have to keep costs in mind.”
Construction has begun on all four communities and all of the houses are scheduled to be completed by March. A few will have grand openings this fall and the houses will be occupied as soon as they’re finished and purchased.
Importance of net zero
Housing accounts for 17 per cent of Canada’s secondary energy use and 15 per cent of greenhouse gas emissions. While significant progress has been made in reducing the energy intensity of individual homes through retrofits and new housing programs, growth in housing stock has contributed to a net 14 per cent increase in household energy use since 1990.
Net zero energy buildings produce at least as much energy as they consume on an annual basis and they’re seen as a means of helping eliminate air pollutants and greenhouse gas emissions from energy production. There’s a goal of making net zero energy housing commonplace in North America by 2030, but Luck said that will be dependent on the market approach.
“It’s not going to happen tomorrow. Even in March, when all of these houses are done and we’ve made a case that it’s affordable and doable, builders aren’t going to start doing this right afterwards. But they’ll offer it as an upgrade.
“Building isn’t the biggest hurdle. It’s marketing or having customers understand that they can have a product that has the potential to be net zero, but it really depends on how you operate it.”
There may also be capacity and infrastructure barriers to overcome before widespread adoption of net zero energy housing occurs, as not every utility or region will allow a home to connect to the electricity grid.
But building codes are moving in the right direction and Luck expects incremental steps towards achieving net zero, citing increases in energy efficiency requirements in Ontario that are starting to be followed by other provinces and at the national level.