How to Build Affordable Social Housing to Passive House Standard

Designing to the Passive House standard of energy efficiency and airtightness is hard. Designing social housing on a tight budget to the Passive House standard is incredibly hard. That's why the work of Emma Cubitt and Invizij Architects is so interesting and important. We previously reported on how a run-down rooming house found redemption as Passive House social housing; now, right next door in a gritty part of Hamilton, Ontario, they have built McQuesten Lofts with 50 one-bedroom residential units, developed for housing charity Indwell "in conjunction with local Indigenous organizations to address issues of Indigenous homelessness."

Indwell is a remarkable organization, "a Christian charity that creates affordable housing communities that support people seeking health, wellness and belonging." It has built over 570 units and was an early adopter of the Passive House standard.

The building has a simple, boxy form; as architect Mike Eliason explains in his article In Praise of Dumb Boxes, "Every time a building has to turn a corner, costs are added. New details are required, more flashing, more materials, more complicated roofing. Each move has a corresponding cost associated with it."

Boxy buildings are also cheaper to operate. As Eliason notes, "Dumb boxes are great from an energy consumption standpoint because they’re more efficient owing to lower surface area to volume ratio over buildings with more intensive floor plans. This has the added benefit of making it easier to achieve high levels of building performance without additional cost or effort."

Breaking down the massing and making it look a little less boxy, "The building’s overall design aesthetic references stacked shipping containers, reflecting its nearby industrial neighborhoods in East Hamilton," Invizij explains. "The shape of the building creates a protected courtyard between the two buildings, with large south-facing communal balconies. On the street-facing portion of the ground floor, a commercial storefront unit is designed to suit a future use with community benefit. The site plan also includes a private dog-park for tenants, as the complex is pet-friendly."

We have discussed shipping container aesthetics before, but I think this is a different kind of project; designing a building like this can be a real challenge, and this part of town could certainly use some color. You really have to compare the before and after photos to get a feel for what is going on here.

Emma Cubitt tells Treehugger that "this is the largest building in Canada going for PHIUS certification, as far as I am aware." PHIUS, or Passive house US, is a standard developed as an American alternative to the PHI or Passive House International and has evolved to have some subtle differences. Asked why she went PHIUS, Cubitt tells Treehugger:

"We first designed 2 PHI projects which are to be certified and one PHIUS which did not go for certification. We wanted to be able to compare the process, cost implications, and benefits of PHIUS designed and certified building so that we could share about that with the passive house community. So, the reason was mostly for curiosity."

We will be following up to find out what she has learned after working with both systems.

The project is also all-wood construction (floors, walls, roof, windows)." It has a simple, affordable wall section with 3 inches of Roxul Comfortboard (compressed rock wool) wrapping around 6-inch studs full of Rockwool batts.

"We have started to replicate it on most future projects because it meets PH targets and is cost-effective," Cubitt says. "It is also close to typical construction with just 3” continuous insulation outside the studs. We are using through-fasteners to hold the insulation/furring for the cladding in place instead of girts or clips to reduce costs and thermal bridging."

They have left the cheap and cheerful industrial look at the front door; once you are inside, it is quite warm and inviting, with interesting wood details in the ceiling and elevator lobby.

We often complain that stairways are ignored, but here the main stair is bright, with views from the hallway and windows to the exterior, a reasonable alternative to the elevator. Perhaps Indwell has met Fitwell.

The units look quite comfortable, and the window doesn't look that small from the inside. The architects were confident enough that they even painted a wall dark grey. Notice also that there is no radiator under the window as is more typical; when you build to Passive House standards, you can put your heating and cooling anywhere because the window and the exterior wall are warm. The fan is probably more useful in winter than summer, pushing the warm air down.

It's all topped off with a 46kW photovoltaic array, which was included in the construction costs of about C$258 per square foot (US$201 at the time of writing) which is really remarkable. It's what one of my architecture professors used to describe as what the best buildings have: economy of means, generosity of ends. Hamilton, Ontario is so lucky to have charities like Indwell and architects like Invizij; no wonder everyone is moving there.