A forthcoming change to B.C.’s Building Code that will require all new homes to have at least one temperature-controlled room presents an important opportunity to build creatively for the future, says an expert in environmental design and sustainable architecture.
The government is proposing that all new homes have a minimum of one living space that is designed not to exceed a temperature of 26 C, through either passive cooling measures, such as shading, or a cooling appliance.
Two years ago, a deadly heat wave killed 619 British Columbians. A coroner’s death review panel found that the majority of victims were older adults with compromised health, who lived alone in homes without adequate cooling systems.
“Mandatory requirements for new buildings will help address the effects of extreme heat events on building occupants to improve public safety and better prevent future fatalities,” said a statement from the Ministry of Housing, provided by communications manager Tasha Schollen. The updated building code is expected to be implemented in December.
Vivian Loftness, a professor of architecture at Carnegie Mellon University in Pittsburgh, with 30 years of focus on environmental design and sustainability, said there are proven design strategies to help cool the home.
These include “cool roofs” designed to reflect more sunlight than conventional roofs, strategic window placement and retractable awnings and other window coverings. Rainscreen facades – a cladding layer separated from the exterior wall by a small gap – offer additional protection against rain, heat and cold.
New condo towers can be built with quiet, high-efficiency heat pumps and dynamic shading devices over balcony windows. Transom windows with exhaust fans can pull cool nighttime breezes through the condo unit.
“The design professions, and the building professions, are perfectly capable of delivering a house that does not overheat as long as the outside air is 30 degrees Celsius or less,” Ms. Loftness said.
“It gets tough to do it when it’s 40 outside, but I think the important thing for the design profession is to not let them get sloppy, not let them just say, ‘Oh, well, we’ll just put in an air conditioner.’ They really have to be held to account for keeping that cooling load just to the hours and the days when the outside is really too hot.”
In Switzerland, strict environmental laws set at the canton level make it difficult to purchase an air conditioner; in Geneva, for example, a homeowner must prove that they have a legitimate need for one. Other cantons require that air conditioners meet certain energy-efficiency standards.
Ms. Loftness said it would be wise for B.C.’s updated Building Code to include some conditions so that builders don’t simply default to air conditioning. A surge in air conditioner usage would contribute to electricity demand, which is already expected to increase by 15 per cent between now and 2030. BC Hydro reported in June that new sources of electricity will be required sooner than previously expected.
Mark Bernhardt, vice-president of the Canadian Home Builders’ Association of B.C. (CHBA BC) and a licensed builder and developer based in Victoria, said recent updates to the Building Code regarding energy-efficiency requirements have already spurred changes in how homes are built and designed. These have included extra insulation, strategic window placement and slightly bigger overhangs on the south side of a single-family home to shade windows.
Exterior roller blinds on east- and west-facing windows is another cost-effective solution that requires little to no maintenance, and basements would likely stay relatively cool, he said. Mr. Bernhardt said condos will be more difficult, citing as an example smaller units with one bedroom, one living room and not many options to reconfigure.
In parts of B.C.’s Southern Interior, where temperatures regularly exceed 30 degrees in the summer, most homes are already being built with cooling devices or the required hookups if the devices are not installed at the time of construction.
“More energy use is not desirable, of course; there’s emissions associated with the electricity use,” Mr. Bernhardt said. “Shifting that demand from the winter, where it’s currently peaking, to the summer, is a really sort of different way of thinking about our grid.”
BC Hydro set a new record for highest August peak hourly demand on Monday when 14 daily temperature records were set and consumption reached more than 8,400 megawatts. That is about 1,000 megawatts more than usual, and the equivalent of turning on about one million portable air-conditioning units, according to the energy supplier.
Mr. Bernhardt said where he foresees challenges is with the existing housing stock.
“You can’t force people to spend money on their homes, as much as we’d like to, in the name of saving people’s lives,” he said. “The hope is that over time, these buildings will go through an upgrade process and solve that problem. But in the meantime, I think we’re going to see a lot of portable air conditioners and things like that.”
Editor’s note: An earlier version of this article implied that B.C.’s electrical needs rely heavily on electricity generated by burning fossil fuels. In fact, BC’s electricity demand is almost entirely satisfied by renewable sources. This version has been clarified to state that B.C.’s growing electricity demand will require new sources of electricity sooner than previously expected.