This was a new house located in Duvall, a small town in King County. The clients were two teachers, one of whom, a high school physics teacher, took a year sabbatical to act as the general contractor for the project. The site is in a rural area on the outskirts of town.
The homeowners goals for the project were to:
- Build a Net-Zero Energy home (incl. an electric car – no utility or gasoline bills for the rest of time).
- Use only renewable/ sustainable/ non-toxic materials (no foam!).
- Make the project affordable.
- Build something that would last for 100’s of years.
- Help revolutionize the building industry.
- Promote Passive Houses for all!
The house is two-stories with an attic, and no basement. It’s traditional in style, but very cutting edge in its performance:
- R-50 walls, R-85 roof, R-38 floor
- Sustainable materials (No foam)
- Vapor open (drys to inside and outside)
- Protected OSB air barrier
- 2/3 Insulation outside of OSB (keep OSB above dew point)
- Space heating by ductless mini-split heat pumps
- Heat recovery ventilator for fresh air
Passive House stats:
- Space Heating – 3.12 kBtu/s.f/yr (below req’d. limit of 4.75)
- Primary Energy – 25.8 kBtu/s.f/yr (below req’d. limit of 38)
- Blower door test results – 0.40 ACH at 50 Pascals!