The content for this article was originally featured in Treehugger on October 20, 2021.
One of the standard tropes you hear about Passive House design is that it is too expensive or too hard or not worth the trouble. And then you have Solis, a new multifamily project in Seattle that has received PHIUS certification, uses 50% less energy than a conventional building, and only costs 5% more than conventional construction. And they got a lot for that 5%.
Architect Bronwyn Barry has noted that Passive House is a team sport. It’s also been said Passive House has a learning curve. Probably the main reason they could pull this off is because it was such an experienced team. The architects were Weber Thompson, which has been on Treehugger many times with their influential 2008 Terry Thomas Building—it was most definitely not a Passive House design.
The Solis project was conceived and built by Sloan Ritchie, who built the first Passive House residence in Seattle—and I believe lives in it. He also previously built the Pax Futura apartment building, which he also claimed had only a 5% premium.
So why should it cost more at all? According to the Cascade Built website, costs were carefully controlled here. “This was done through the use of conventional materials in innovative ways including pairing an enhanced building enclosure with a top-notch mechanical system for exceptionally comfortable and healthy units.”
Passive House designs have more insulation and more expensive triple-glazed windows, so the exterior wall can be significantly more expensive than a regular building. However, because it is multifamily, the exterior wall is a much smaller proportion of the cost of the building, just one or two walls per unit. But it is also a marketing advantage, earning its keep in comfort and quiet.