R9 windows positioned to make big difference
April 5, 2008
Elvira Cordileone
STAFF REPORTER
The three-unit Top of the Annex Townhomes infill development will incorporate high levels of insulation and advanced window glazing to cut energy demands, says project architect Lou Ampas, a principal with Coolearth Architecture.
To be built on Davenport Rd. near Avenue Rd., each of three 2,500-square-foot townhouses will have wall and roofing insulation ratings of R60 and R76, respectively, compared to R28 and R19 minimum building code requirements, Ampas says.
Since most of the heat loss will be through windows, they'll be R9-rated, compared to a typical good new window, which rates R2, he says.
In addition, Ampas says windows will be positioned thoughtfully to best capture solar heat and light and to deal with obstructions caused by surrounding buildings and trees.
To further enhance the effect of the sun's heat, the design turns the usual placement of living spaces upside down: the most-used rooms, the living areas, sit at the top, where it's warmest and brightest, to reduce the need to heat and light them.
Ampas says the homes will have ground source heat pumps for cooling and heating, powered by electricity generated through photovoltaic cells on the roofs.
While residents may need to draw power from the electricity grid during peak periods, they'll feed the power the houses generate back into the grid when they produce more than they need.
In the course of a year, Ampas says each unit will create as much power as it consumes – R100 or net zero energy.
(Natural Resources Canada's EnerGuide rating chart indicates a house that uses little or no purchased energy, such as EQuilibrium's demonstration projects, rates 91 to 100; an energy efficient new house, such as those carrying the Energy Star label rate R80; an energy efficient upgraded old house or typical new house rates R66 to R74.)
Ampas says the units cost 25 per cent more than a townhouse built to Ontario building code minimum standards, with sticker prices of $900,000 to $1.2 million.
But owners would not only save money on energy bills, they'll never have to worry about energy shortages in the future.
"The interest of people wanting to buy a unit site unseen is amazing," Ampas says.
Ryerson University's faculty of engineering, architecture and science and Coolearth Architecture head the Sustainable Urbanism Initiative project team.
Toronto Star