This is a new house located in Duvall, a small town in NE King County. The clients were two teachers, one of whom, a high school physics teacher, took a 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+ 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);
- no thermal-bridging;
- protected OSB air barrier;
- 2/3 Insulation outside of OSB (keep OSB above dew point);
- triple-glazed windows;
- space heating by ductless mini-split heat pumps;
- heat recovery ventilator for fresh air;
- heat pump water heater;
- 10 kW PV array.
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!