The first spec home in the Pacific Northwest to meet Passivhaus standards is in the Columbia Station green micro-community built by the award-winning design+build boutique firm, Dwell Development. Passivhaus is an energy standard that is more difficult to achieve than LEED with respect to energy efficiency. Homes that meet the Passivhaus standard must reach thermal comfort levels by postheating or postcooling fresh air without necessitating recirculation.
â€œWe made the committment to building a Passivhaus on spec because we believe so strongly in creating energy efficient homes and keeping them affordable,â€ said Dwell Development principal, Anthony Maschmedt, in a recent press release. â€œItâ€™s paying off now. The home pre-sold in November 2012, in the early framing stage of the project.â€
In mid-February, Dwell conducted a blower door test that â€œresulted in 0.58 ACH50, or .58 air changes per hour under 50 pascals of pressure.â€ By comparision, regular code homes change air at a rate of around seven times per hour under 50 pascals of pressure. Energy Star standards permit up to 5 or 6 air changes per hour.
The three-bedroom, 2.5 bath home is part of Columbia Stationâ€™s Phase 4 and features a super-insulated building envelope, heat recovery ventilation, airtight construction, reduction and elimination of thermal bridging, high-performance windows, and a reliance on passive heat sources with the aim of reaching 90 percent efficiency.