Students at the Endeavour Centre in Ontario helped build a net-zero-energy spec house a few years ago and called it “Canada’s Greenest” when they were finished. There is, of course, no way to prove that, but now they can show just how energy efficient the building is.
The school tracked energy consumption at the 2300-sq.-ft., two-story house between October 2013 and September 2014, logging the amount of power used every month against the amount produced by the home’s 5kw photovoltaic system.
Although total output was 2792kwh less than consumption, some months were so profitable under the province’s feed-in tariff system that the house actually netted $2000 by the end of the year. Chris Magwood, project director and executive director of the school, says that unlike net-metering, which is common in the United States, under Ontario’s Micro-FIT system, the house has two meters–one for outgoing power (which earns 38 cents per kwh) and another for power that’s purchased from the grid (11 cents per kwh).
Three adults, including Magwood, and a child lived in the house during the test period. Compared with averages for a 2500-sq.-ft. Ontario home, the Endeavour House used about 70% less energy, a total of 8867kwh.
Equipped with a rainwater collection system and a composting toilet, the house also used 71% less water than the provincial average: 66 liters per person per day vs. 225 liters (17.4 gal. vs. 59.4 gal.).
House uses prefabricated straw panels
In addition to building in energy and water efficiency, designers also tried to lessen the project’s environmental burden in other ways.
Magwood wrote that 90% of the materials used in the house were sourced within 250 km (155 miles) of the job site and that construction waste was a total of 852 lb., or roughly 10% for a typical 2000-sq.-ft. house in the region.
“It didn’t take government grants, corporate R&D or high-tech components to make the home,” Magwood wrote. “Every material and system used was an off-the-shelf item available to any builder, and the home was largely built by students in The Endeavour Centre’s Sustainable New Construction program.”
The walls were assembled from prefabricated straw-bale panels 8 ft. tall and 3 ft. wide. The 16-in.-thick panels, finished with drywall and plaster on the inside and stucco on the outside, have a two-hour fire rating and an R-value of 35.
Other features include a foundation made from insulated concrete forms, triple-glazed windows, a composting toilet, an air-source heat pump, solar thermal collectors for hot water, and triple-glazed windows.
The project was described in more detail in an earlier post at GreenBuildingAdvisor.com and in a blog posted at the school’s website.
Lessons learned for next time
Were they to build again, Magwood said a few things would be handled differently.
- No full basement. The house has a full basement, mainly to accommodate a Clivus Multrum composting toilet. Since then, Magwood has discovered an alternate system called the Envirolet vacuum-flush system that doesn’t require a full basement. Building on a slab or over a crawlspace would have saved roughly $25,000.
- More efficient ductwork. “We couldn’t find anybody who would stand behind a design with the outlets in the central walls of the two floors, and we ended up with old-school ducts under each window,” Magwood wrote. “We’ve since found a licensed heating designer who would have stood behind such a design, saving quite a bit of money and material.”
- Water storage outside. Instead of putting rainwater storage in the basement, it could have gone outside the house at a lower cost–another reason not to build a full basement.
- Make the house a duplex. A key change would have been to turn the single-family design into a duplex. “This would have made the slightly higher costs for the more efficient systems/materials a much easier sell from a financial point of view,” Magwood said, “and also contributed more to urban density.”
Construction costs were $398,000, or $173 per sq. ft. Rainwater collection, the composting toilet, and renewable energy systems accounted for $46,500 of the total. The construction budget also paid for 2.5 full-time instructors as well as professional trades.
The house is expected to go on the market this spring.
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This high-performance spec house in Ontario was billed by its creators as the country's greenest home. The Endeavour Centre now has energy performance data for a full year.
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Many green initiatives have been in the rise over the past few years to encourage a more environmentally-friendly lifestyle for all. People are strongly encouraged to develop their own green house or they should consider moving to a ready made one that has all the fixtures necessary to support the living concept. Not only can they save living costs but also help save the environment.