They are buildings so energy efficient they don't need a furnace, an air conditioner or any other kind of active climate control to keep their residents comfortable through the sticky summers and icy winters in many parts of Canada.

"Passive houses" are buildings that rely on insulation, ventilation and heat from their occupants or sun falling on them to maintain the perfect temperature.

In Canada, up until now, they've mostly been single-family dwellings — green dream homes for those who can afford them. But now, builders using international passive-house design principles and standards are scaling up to big apartment buildings.

The pioneers on this new frontier aren't custom home builders for the rich and eco-conscious — they're non-profit organizations that build affordable housing. And they're promising more comfortable apartments with extremely low utility bills for some of Canada's most vulnerable residents.

Graham Cubitt of Hamilton-based social housing provider Indwell spoke about his organization's passive-house projects at the Buildings Show in Toronto last week. He said most current multi-residential projects trying to incorporate passive-house design are tied to 'some sort of affordable housing target.' (Evan Mitsui/CBC)

The first multi-residential passive-house apartment building in Canada was completed just last year. Karen's Place in Ottawa is a four-storey building with 42 bachelor apartments. Also known as Salus Clementine, the modern-looking building has been fully occupied since February by people with severe mental illness, half of whom were previously homeless.

They pay $489 a month, including utilities, for apartments that are designed to use 66 per cent less energy than if the building were built to the standards of the 2012 Ontario Building Code. Each unit costs about $30 a year to heat.

'Natural fit'

Lisa Ker, executive director of Ottawa Salus Corp., the non-profit organization that runs Karen's Place, said the rental rate for people on a disability pension is set by the province, and it hasn't changed in years despite rising costs. That's forcing social housing providers to look for ways to save on operating costs like utilities.

Building green is a natural fit for the affordable housing sector just out of sheer necessity. - Lisa Ker, Ottawa Salus Corp.

"Building green is a natural fit for the affordable housing sector, just out of sheer necessity," Ker told CBC News.

It tends to fit with the values of organizations that are trying to make the world a better place, and to serve the vulnerable people who will be most affected by climate change, she said.

The new building has given residents a sense of pride for being part of the solution. Many are keen to open up their homes and share their experience with visitors touring the building.

"It's amazing," Ker said.

Salus won a 2017 Ontario Non-Profit Housing Association innovation award and has inspired other social housing providers in B.C., Alberta, Manitoba and across Ontario, Ker said.

Among them is Indwell, a Christian charity that's building two passive-house apartment complexes in Hamilton, each with around 50 apartments for people with mental illness and other disabilities. One also includes a church and community space. Indwell has also started work on two others in Oxford County in southwestern Ontario.

Graham Cubitt, director of projects and development for Indwell, said most current multi-residential projects trying to incorporate passive house design are tied to "some sort of affordable housing target."

Climate targets

That's partly because governments are trying to hit two birds with one stone by including climate change targets when they put out requests for proposals for social housing projects, he said after presenting at the IIDEX Buildings Show in Toronto last week.

According to the most recent report from the Intergovernmental Panel on Climate Change, buildings generate about 20 per cent of global greenhouse gas emissions linked to human-caused climate change, and 47 per cent of all indirect emissions from electricity and heat production.

Canada is one of the 196 countries that signed onto the 2015 Paris accord, committing to cut greenhouse gas emissions. Canada has committed to cutting its emissions to 30 per cent below 2005 levels, but has only reduced emissions about two per cent so far.

Governments are starting to recognize that making buildings more efficient is one of the simplest ways to get closer to meeting their climate change targets.

Hughson Street Baptist Church is a mixed-use passive-house development that Indwell is building in Hamilton. It will include a church and about 45 units of affordable housing. (Indwell)

Jamie Stephens, manager of housing development for Ontario's Oxford County, said everyone needs to be concerned about climate change in everything they're doing.

Her own municipality committed in 2015 to relying on 100 per cent renewable energy by 2050. Given that and climate change priorities of other levels of government that fund social housing, she said, "it only makes sense to be trying to achieve a much higher energy performance in any publicly funded projects that we're involved with."

That includes Blossom Park, a complex that Indwell is building in Woodstock, Ont., that includes a 26-bedroom residential care facility and 27 supportive-housing apartments for people with mental and physical disabilities.

Growing pains

Pioneering the techniques needed to build passive-house buildings on a bigger scale hasn't been easy — likely one of the reasons that private developers have been slower to jump in, although it's starting to happen.

Blossom Park is a passive-house complex that Indwell is building in Woodstock, Ont., that includes a 26-bedroom residential care facility and 27 supportive-housing apartments for people with mental and physical disabilities. (Indwell)

Karen's Place cost $9.1 million to build, an estimated six to nine per cent more expensive than a similar complex built to code, Ker says. Design and construction were challenging.

"It was a huge learning curve."

Cubitt says Indwell's first two passive-house developments took a year to design, compared to three or four months for a traditional building. They also cost about five per cent more. But he thinks Blossom Park might be on par with a traditional building for costs.

"Hopefully we can get the price even more competitive than the market so that adopting this won't be impossible for either the affordable sector or the market sector."

Both Salus and Indwell are now sharing their knowledge with others. Salus provides tours to developers, including many in the private sector.

Stephens already plans to offer tours of Oxford County's green social housing projects to local builders and hopes it will encourage them — and maybe even manufacturers of building materials like high-performance doors and windows — to become leaders in passive-house building.

"We want to show this can be done," she said. "There's lots of economic and job growth opportunities by changing the way these projects are being constructed."