Early in the new year, the Hamilton YWCA will open a 50-unit affordable housing complex fitted out with a full complement of energy efficient design elements: extra-thick, heavily insulated walls, triple-glaze, high R-value windows and air-tight exterior cladding designed to minimize conductive heat loss.
The project, designed by Kearns Mancini Architects Inc. (KMAI) and partially funded with a $10-million grant from a federal housing co-investment fund, will be Canada’s first completed mid-rise “passive house” certified buildings. These structures can achieve up to 90-per-cent reductions in operating costs because they retain and reuse heating and cooling far more effectively than traditionally designed buildings.
The Hamilton Y’s construction costs have come in at about 2.5-per-cent to 5-per-cent higher than the typical rate, but KMAI principal Jonathan Kearns says the premium on capital costs will be recouped within about two years due to the sharply lower energy outlays associated with passive house design.
The exacting German environmental standard has been popular in Europe for two decades, and has caught on in recent years in B.C. due to the increasingly stringent building codes there.
KMAI is positioning itself as a passive house shop in response to federal and municipal climate policies promoting so-called net zero buildings; in fact, the chief operating officer, Deborah Byrne, was one of the founders of Passive House Canada. The firm’s next major PH ventures include a 10-storey apartment in Windsor, Ont., called Meadowbrook and work on a 750-bed residence at the University of Toronto’s Scarborough campus where it was responsible for supervising design compliance to Passive House standards.
While many early Canadian passive-house projects are affordable or institutional multi-unit residential housing, the same design principles have been adapted for high-end residential architecture, as Mr. Kearns himself can attest.
He and his partner, Corrine Spiegel, have completed two PH projects in Ontario’s Prince Edward County and are planning several more “at a very relaxed pace,” as he put it recently.
They started visiting the Prince Edward County in the 1980s when their kids were young. In 2015, the couple acquired a property with a 1890s post-and-beam guest house they dubbed “The Reach.” Mr. Kearns and Ms. Spiegel stripped off layers of accumulated stucco and drywall until they reached the original structure. Then, with the help of a contractor knowledgeable in PH design, they began to backfill the energy efficient elements. “The house became an inside-out production,” Mr. Kearns says.
The Reach, he explains, has been “encapsulated” within a second skin – a new roof packed with R70 insulation, 14-inch walls made from structural insulated panels and wood siding, and triple-glazed, recessed windows. In a somewhat tricky maneuver, the contractors also managed to underpin the ground floor with additional insulation to create a barrier against the chilly basement and the original stone wall foundation, itself a major conductor of cold.
The house is fitted out with an energy recovery ventilation system (ERV), an important feature of PH projects. ERVs continuously circulate and filter fresh air – there are 0.3 complete air changes an hour – while capturing waste energy with a heat exchanger.
The monthly energy bill for the 1,600-square-foot dwelling is just $100. “To me,” Mr. Kearns says, “The Reach was a laboratory project. I learned a lot about passive house in the approach.” Since completing it in 2018, he and Ms. Spiegel have undertaken a far more ambitious PH venture in Prince Edward County – a “great house” on the crest of a hill on a ten-acre site, dubbed Endymion, a randy figure from Greek mythology.
A three-level, 3,600-sq.-ft insulated concrete dwelling in the shape of an elongated rectangle with a south-facing façade, Endymion is effectively two conjoined homes connected by a central staircase. The internal program is meant to enable guests – Mr. Kearns and Ms. Spiegel have five grown children with their own families – to use a self-contained space while visiting.
Besides the 12-inch walls, heavily insulated and PH-certified glazing (see sidebar), Mr. Kearns' design features deeply inset windows that produce shade in the summer and bring in thermal energy during the winter. “The windows,” he explains, “are part of the heating system.”
But so are a host of far less sexy details, which, in the aggregate, will deliver the drastic energy reductions that differentiate passive-house projects from other less demanding environmental standards. In the case of this project, Mr. Kearns notes, for example, the use of vent-less dryers, as well as building’s flat roof, which is intended to eventually accommodate solar panels.
Unlike a more conventional design, roof access is via an exterior ladder instead of an interior stairwell in order to minimize the number of openings, and therefore energy leaks, in the building envelope. “The only holes in the roof are the vent stacks in the bathrooms,” Mr. Kearns says. With those, the ERV is already siphoning off the waste heat before it disappears into our warming atmosphere.
Globe and Mail Real Estate is exploring the evolution of passive house design in Canada, including the development of a townhouse pilot project being built by Toronto Community Housing and Tridel in Alexandra Park.
Made-in-Canada passive house-certified windows
One reason passive-house design has been slower to catch on in North America has to do with access to certified components, such as highly insulated windows and specialized heat recovery systems. These elements are widely available in Europe, but Canadian builders, until recently, had to import them, adding to project capital costs and reduced margins.
Two years ago, Cascadia, a Langley, B.C.-based window manufacturer, decided to fill one of those supply chain gaps, introducing a line of PH-certified windows geared at both residential and commercial projects.
President Mike Battistel says the decision reflected the firm’s reading of the direction of both the market and regulation. B.C.'s provincial building code, also known as the “step code,” is steadily ratcheting up energy efficiency requirements, meaning developers will need more high-efficiency materials in the near future. “We realized everything was moving in that direction, but there were no solutions for passive-house windows suitable for commercial grade construction.”
Cascadia’s R&D team, he says, responded by developing (and then patenting) the first PH certified windows to be manufactured in North America.
Unlike most windows made with aluminum or vinyl frames, Cascadia’s engineers developed a hollow fibreglass version injected with polyurethane insulation. The glazing is a triple-pane construction with argon gas and the assembly is designed to minimize air and water penetration – one of the key design goals of all passive-house buildings. Mr. Battistel says the r-value, a measure of insulation effectiveness, exceeds R-7 (most triple glaze windows don’t go beyond R-5) and is about 15-per-cent to 20-per cent more expensive than conventional products.
Cascadia’s PH-certified windows are now being installed in various projects, including a deep retrofit of a Hamilton community housing tower and a Vancouver new-build called The Chelsea, mid-rise residential project by Cressey Development Group.
Mr. Battistel says the market is responding well to Cascadia’s first mover strategy. About 15 per cent to 20 per cent of units sold are now PH certified, and another 50 per cent are triple glazed, with slightly lower R values.
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