Now, that’s not to say that meeting the Passivhaus standard in certain localities is a walk in the park – it’s certainly difficult in many places, like Siberia; the north slope of a steep, east-west valley (GraubÃ¼nden!); Fairbanks… That being said, there are projects (certified, even) that meet the Passivhaus standard in climates north of 7,000 heating degree days (HDDs) – and with the advent of something like Super Windows – well, much of that nonsense could become completely moot.
In the next year, I’m certain we’ll see several more projects that disprove the cost-ineffectiveness of meeting 15 kWh per square meter in cold climates. It is definitely something that merits debate – but hey, it’s not like anyone’s been censoring posts, or anything…
Chris Corson’s Maine Passivhaus
The first project is the house that Chris Corson (the owner of EcoCor Design/Build) recently wrapped up in Knox, Maine. The project has seen some good press (including a GBA story) and great praise recently – I ran into many people at the recent Passivhaus conference in Hannover, Germany, discussing it, including some Canadians and Germans.
The 1,600-square-foot two-bedroom house sports a treated floor area of 1,140 square feet (106 m²), which some would say falls under the “small” category. It also happens to be a detached home in a really cold climate (modeled at 7,345 HDDs). Chris was able to bring the cost of construction to under $130/sf.
The modeling bests the specific space heating demand, coming in at 3.11 kBTU/ft²a (9.82 kWh/m²a). This was done through a combination of superinsulation, phenomenal windows (from Intus) and a phenomenally low blower door test of 0.286 ach50.
The most impressive bit about getting the space heating demand so low, outside of achieving affordability in a difficult climate, was leaving wiggle room for future additions or modifications. Furthermore, cost savings may have been realized by dialing back the insulation closer to 4.75 kBtu/ft²a.
G•O Logic’s red house
The second project is G•O Logic’s 1,500-square-foot, three-bedroom Passivhaus in Belfast, Maine – just down the road from the project above (by the way… WTF is up with Maine?!?).
This one also garnered lots of press, and recently snagged a LEED for Homes Project of the Year award. Yup, they were able to garner PH and LEED Platinum certifications for ~$160/sf. You can read up more on the project at Maine Home + Design.
The NewenHouse Passivhaus in Wisconsin
The third project throwing a wrench in the ever-weakening argument is the Ã¼ber-compact NewenHouse in Viroqua, Wisconsin (7,795 HDDs), with Carly Coulson as the certified Passive House designer. This tiny (968-square-foot) kit house has a treated floor area of 888 square feet (82.5 m²).
This project sports local windows and Cardinal triple-pane glass, while the doors are Energate. Like the Knox, Maine, Passivhaus, the NewenHouse is wrapped in a jacket of cellulose – and similarly comes in well under the specific space heating demand.
Carly recently presented the project at the Hannover Passivhaus conference. Here are some of the project specs:
- Space heating demand: 11.4 kWh/m²a (3.61 kBTU/ft²a)
- Primary energy demand: 104 kWh/m²a (32.9 kBTU/ft²a)
- Blower door: 0.51 ach50
- Wall U-factor: 0.09 W/m²K (R-63)
- Slab U-factor: 0.10 W/m²K (R-57)
- Roof U-factor: 0.06 W/m²K (R-94)
The project is also rocking a solar domestic hot water system (Velux) that is expected to provide nearly two-thirds of the domestic hot water needs, and a PV system for site net zero energy.
The project went through BRE in Watford, UK, for Passivhaus certification, is Energy Star certified, and is expected to hit LEED for Homes Platinum.
Total cost for NewenHouse – including solar DHW, PV, and accessory structures – is a whopping $173/sf. If there was a LEED Titanium, this Ã¼ber-tiny Passivhaus in an “extreme” environment would surely qualify.
While these may not be the modernist jewels we tend to drool over – these are sound, extremely cost-effective houses and further proof that there is more of a bad design/shoehorning penalty in extremely cold climates – rather than a detached housing one. And if locally made PH windows and glass ever become available, that cost-effectiveness will only improve.
Mike Eliason is a designer at Brute Force Collaborative in Seattle, Washington.