|The Ballard house’s 6.4 kW PV system was planned for future expansion, which would provide power for an electric vehicle.||Rainwater collection reduces the load on storm drains and provides some water storage.||Eric and Alexandra make the commitment to net-zero energy.|
This single-family home was the first net-zero energy house in Seattle, Washington. Owners Eric Thomas and Alexandra Salmon built it in part as a platform for sharing what they’ve learned. They help organize public tours of homes in the area, and started a series of free green-building talks that bring in experts to speak at green-built or green-retrofitted homes in the neighborhood. Their blog—zerohouse.wordpress.com—documents the building process of their home, as well as provides information on local green home talks and tours.
Recently married and on a tight budget, Eric and Alexandra demonstrate that net-zero energy building doesn’t have to be the domain of the wealthy. By using stock plans, avoiding costly additions (like granite counters), and keeping focused on net-zero energy, they kept building costs to $124 per square foot (including the PV system)—much less than Seattle’s average of $200 per square foot.
Absent from their home is a heat recovery ventilator (HRV). In Seattle’s mild climate, the amount of heat recovered by an HRV is outweighed by the electricity needed to run it. HRVs are essential to serious efforts to conserve energy in very cold climates—they just don’t make sense in the maritime region of the Pacific Northwest. In this house, adequate air exchange is provided by exhaust fans.
Similarly, in this climate it was cheaper to add more PV capacity to heat water electrically with a heat pump than to add a SHW system. And the extra room on the roof may one day be used to PV-power an electric car.
|An air-to-water heat pump sends energy to the hydronic in-floor heating system, seen here before the concrete slab was poured.||Structural insulated panels make for a quick-to-assemble, well-insulated envelope.||The Interior of the finished home.||Even with 100% electric heat, the gridtied PV system is producing surplus energy.|