DOE Tour of Zero: Greenlake Cottage by Bellingham Bay Builders
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Bellingham Bay Builders built this 752-square-foot custom home in Seattle, Washington, to the high performance criteria of the U.S. Department of Energy Zero Energy Ready Home (ZERH) program.
Durable fiber-cement siding and trim protects the exterior in the damp northwest climate.
All interior and exterior lights in the home are supplied with LED bulbs.
The sealed concrete floors provide thermal mass for passive heating that supplements the 800-square-foot home’s single mini-split ductless heat pump.
ENERGY STAR-labeled appliances in the home include a refrigerator, dishwasher, ceiling fan, and exhaust fans.
Four inches of rigid foam, a 6-mil vapor barrier, and a bed of gravel separate the ground from the slab, providing both a thermal break and a capillary break to keep the floor warm and dry.
The coated OSB sheathing is sealed at the seams with a paint-on flashing to provide a seamless weather-resistant barrier over the walls. A paint-on flashing seals and protects the window sills.
The double-pane windows have low-emissivity coatings and an argon gas fill between the panes to boost their insulating value to a U factor of 0.25.
Three inches (R-12) of cork insulation covers the walls and the unvented roof deck of the home.
Fiber cement lap siding will attach to the 1-by-4 wood battens, which also provide a ventilating air gap between the siding and the cork insulation.
“This house is so comfortable! The temperature is never hot or cold.”
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"This house is so comfortable! The temperature is never hot or cold.”