Every House Should Be a Passive House

As we noted after the United Nations' Intergovernmental Panel on Climate Change (IPCC) report, every ounce of carbon dioxide emissions adds to global warming. It's one reason I have always been a fan of the Passive House concept, where buildings (not just houses) are designed to minimize heat gain and loss. It should probably be the legal minimum, as it is in parts of Europe.

The Saltbox House, designed by L'Abri and built by Construction Rocket, built on a hillside in Bromont, Quebec, shouldn't be our poster child in a discussion of the future of green building post IPCC. It's a big 3,100-square-foot single-family house in the country. But it does have a lot of interesting attributes that more homes should have, and it is LEED Platinum and PHIUS 2018+ certified.

According to the architect:

"The basic principles of the standard are simple: a highly insulated and very airtight envelope, superior heat recovery of the mechanical ventilation system and a design which optimizes the orientation and sizing of openings to promote passive heating of the building."

But much depends on the form and shape of the house, and how it is sited. "The house borrows its silhouette from the vocabulary of rural Saltbox-type buildings which sprang up in 17th century New England and which still pepper the countryside of the Eastern Townships."

Passive House proselytizer Bronwyn Barry often says "Passive House is a team sport" and it certainly shows in the Saltbox House:

"Achieving the performance criteria of a passive house is only possible with the close collaboration of the architect, the consultants and the builder, which is why we favoured an integrated design approach from the very start. This experience confirmed to us that a building can be both aesthetic, in harmony with its environment and extremely efficient."

The builders have an interesting take on how they got interested in healthy and efficient buildings:

"Renovating sick houses gave us a deep appreciation for the new tools and techniques that promote the longevity and health of the house and those who live in it. Our climate can be brutal on building envelopes but the technology and practices exist and we are committed to using them and retooling to create energy-efficient, beautiful homes."

Some find the limitations in Passive House design difficult to cope with; you want to minimize jogs and bumps that create thermal bridges, and lean toward simple forms. The classic New England saltbox lends itself perfectly for this, as I noted in "Party Like It's 1799 in Your Colonial Dumb Box." I wrote:

"There were good reasons for the colonial designers to build their houses this way: simple boxes enclose more space with less material. Windows are small because they are really expensive compared to wood siding. Shingles were usually wood, so you want a steep roof to shed snow and water quickly."

This is also true in Passive House designs, in a cold climate like Quebec, the windows are expensive and they can't be too big. So you want it to be, as Bronwyn Barry hashtags it, #BBB or "Boxy But Beautiful." This takes skill, as I note in "Buildings Can Be Boxy but Beautiful if You Have a Good Eye." The architects, L’Abri, definitely have a good eye.

Their work also reminds me of a dictum I learned in architecture school, that windows are not walls, but should be thought of as picture frames that enhance a view.

The windows here are lovely. They are triple-glazed with frames made of Unplasticized polyvinyl chloride (UPVC) which are certainly not my favorite but are much more affordable than other materials.

Other material choices are more Treehugger correct; the retaining walls are excavated stone, the walls are double-stud with cellulose insulation and wood siding. You can't beat that for low upfront carbon. The grey steel roof is "discreet and timeless."

The architects note that Passive House can be "an answer to the climate crisis." Indeed, what the Saltbox House demonstrates is that you can design a house with minimal upfront carbon emissions by using local and natural materials, and negligible operating emissions by building to the Passive House standard. It's also nice that the little bit of electricity that they might need comes from Quebec's water-powered carbon-free grid.

There are not a lot of Passive House buildings in Quebec; the architects say this is just the third to obtain certification. But they want to spread the word and say they want to "share our personal experience with architecture and construction professionals. For our firm, this initiative is part of a broader approach that aims, through projects of all types, to approach ecological architecture in a holistic way."

In this climate crisis, we need more Passive House and more sharing. The Saltbox passive house demonstrates that it is possible to have beautiful, comfortable homes that still have low carbon footprints.