House Plans Can Help Make Passive Design Solutions Go Mainstream

Engineer Natalie Leonard founded Passive Design Solutions in Nova Scotia to build energy-efficient houses, mostly certified to the Passive House US (PHIUS) standard. However, many prospective clients for houses were not interested or didn't want to spend the money or time on hiring an architect, so she developed a couple of house plans as a loss-leader to simplify the process. Now, a few years later, and with the help of a Women's Entrepreneurship grant from the National Research Council of Canada, the house plans are flying off the shelves, and have grown to become 40% of her business.

This should not be a surprise; it is more of an indictment of the architectural profession that with few exceptions does custom plans for wealthy clients. Some architects, from Frank Lloyd Wright to the late Hugh Newell Jacobson were happy to sell plans; Wright thought that he was democratizing architecture and making it available to everyone. Given that it seems that 90% of North American houses are basically versions of about four basic plans with three bedrooms and two and a half baths, it's a big opportunity.

What Passive Design Solutions does that is different from the usual stock plan vendors is they design the house to meet the PHIUS standard. This is not just a matter of adding insulation and managing airtightness; it is about optimizing the design, getting the orientation right, putting the windows in the right place (not too many on the north or west sides). It's also about the shape and form; as Leonard notes, "Using compact building shapes that reduce exterior surface area and opportunities for air infiltration and thermal bridging." The result is a building that uses as much as 90% less energy than an average house.

It doesn't even necessarily cost any more; Leonard told Treehugger that with the savings in mechanical systems and the simpler forms, they often cost the same as a conventional house. She notes that right now, materials are very expensive so that the difference in cost might be a bit more, "about the same cost as a granite countertop in the kitchen."

I am showing one particular house design, the North Glen, because I have been talking about the basic form on Treehugger for years. The particular home in the photos is on Lake Huron in Ontario, Canada, and is completely off-grid, which is a lot easier in a passive design where the heating load is so low. The design has its roots in what I have described as a colonial dumb box, noting earlier:

"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." 

Tedd Benson of Unity Homes builds a flatpack version, and told me: "Years ago, I met a contractor in Montana who simplified his estimating by charging a set amount for each inside or outside corner. Not surprisingly, most of his clients chose simple boxes, and the designers found ways to find little surprises in the vernacular of the familiar." It has done the job for hundreds of years; Plant Prefab just introduced one. When I was in the prefab business I commissioned plans from top architects, yet sold five of these for every one of the fancy plans.

The plans have evolved over the centuries; there are now wide open "great rooms" stretching across the width of the home, and main floor offices that can swing into main floor bedrooms for aging in place. But conceptually, it is still a basic box.

The great benefit of selling plans is that they can go anywhere; modular can only travel short distances, flat pack a bit farther, but these houses can be found as far north as Inuvik. The PHIUS standard differs from the original Passivhaus in that it is tuned to local climates, and if the house is in the far north they adapt the insulation accordingly.

The downside is that the client is just buying plans, and works with a local builder, so quality control can be an issue. But Passive Design Solutions says "our experience has proven that any builder who is interested in learning how to build Passive can do it. Our drawings are clear, comprehensive, and detailed, taking into consideration conventional building materials and techniques. If you can build a house, you can build a Passive House!"

Years ago I wrote that good architects selling good plans is a good thing. But selling houses designed to PHIUS standards is an even better thing, making them affordable and accessible to a much larger market. In that post, written in the last economic crisis, I concluded:

"The traditional model of the profession is broken. Now, in the current housing crisis, the traditional development model is broken as well. Instead of sitting on their hands waiting for the phone to ring, why don't all of the underemployed architects flood the internet with plans for small, green, efficient, and lovely architect-designed plans?"

Natalie Leonard may not be pleased with my inviting the entire profession to compete with her, but she is a terrific role model, showing her local market how to build an efficient home, and building a new business helping people do it everywhere. We need so much more of this.

I learned about Natalie Leonard during a Passive House Happy Hour; here is a recording of her presentation;