Healthy, Resilient, Passive: A Look at One of Canada’s First EnerPHit Homes
Homeowners Tracy Johnson and Kevin McKenny were looking for a home to retire in. Allergic to many toxic building materials, they wanted a home with good air quality, a home with reduced energy demands and a home that displayed their mindfulness of limited resources for future generations. They knew they wanted a healthy house, a resilient house and ultimately a Passive House, but they weren’t sure how to go about it. They needed a mentor on the subject and reached out to various consultants, ultimately deciding on German Vaisman, a Passive House architect working with Cool Earth at the time. Curious to learn, Vaisman proved to be quite the comprehensive teacher for them, bringing the couple along to various Passive House conferences and tours.
Open to the idea of a new build or a retrofit, Tracy and Kevin ultimately decided on a property that would undergo a retrofit and extension. The chosen property, 51 Sammon Ave, located in the Danforth area, was about 80 years old before they began construction. The 2-storey home originally featured 1200sqft of space, but with the addition of a 500sqft extension, the completed project now totals 1700sqft. “With the addition of the extension, I didn’t think we would qualify to certify under EnerPHit, Passive House Institute’s retrofit certification option,” says Vaisman, “we thought we might aim for Passive House Classic due to the partial new build, but it turned out we did qualify for EnerPHit. Which is nice because EnerPHit is the less stringent option in comparison. For example EnerPHit demands an ACH of 1, compared to the 0.6 required for Passive House Classic. We haven’t certified yet, but we will be submitting our package for consideration soon.” The extension features a living room and kitchen, while the old kitchen is now the entrance and the old entrance, now a laundry room.
Unsurprisingly the project was not free from its share of challenges. The roof needed a lot of added insulation and a vented cavity needed to be built on top of the existing roof to reduce thermal bridging. The basement was lowered, and asbestos was cleaned out. Non-toxic materials were a priority, so the home is almost entirely insulated with cellulose.
Austin Todd, of CoEfficient Building Science, was hired to perform several airtightness tests for the project. “We had to do quite a bit of testing. It was one of the final barriers standing between the project and EnerPHit certification. Every time we tested, we found a number of deficiencies, and we still weren’t where we needed to be. We didn’t have access to certain areas to test, because of the existing wall assemblies, we did not want to disturb the exterior brick, whereas if it were a new construction it wouldn’t be as complex. Because we didn’t want to touch the exterior, insulation was solely added to the interior, except for the added extension that was built onsite. We performed two preconstruction tests, and then a final test, after the residents moved in. The introduction of Aerobarrier sealing finally got us to our goal. It’s a product getting a lot of coverage right, it is great for retrofits.”
Vaisman is really proud of his work on the project and offers some words of wisdom for other architects considering EnerPHit, “the air control layer and transitions can really be a struggle if you aren’t planning on demolishing any walls, because when you start opening up the cavities you realize things are not as you assumed while in the design phase. Try to build in contingencies for that if you can.”
Homeowners Tracy Johnson and Kevin McKenny are also really proud of their new home. They were able to move in early March, just a week before the province went into lockdown due to Covid-19. The air quality of their Passive home has provided the relief they were looking for, but they are most proud of the architectural design. “It is a successful project because they are happy with it,” says Vaisman, “because it is one of the first EnerPHit projects in Canada, but also because we collaborated and communicated really well with each other throughout the project. I’m really proud of that.”