DOE Tour of Zero: Birch House by Bundle Design Studio
Photos
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Bundle Design Studio built this 2,065-square-foot home in Bellingham, Washington, to the performance criteria of the U.S. Department of Energy Zero Energy Ready Home (ZERH) program.
Photo courtesy of Bundle Design Studio
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Sliding wooden screens provide shading on south-facing windows, while the planted “green” roof helps control storm water runoff.
Photo courtesy of Bundle Design Studio
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Over the 2-by-6 framing, the builder installed a continuous thermal blanket, draft protection, and water barrier consisting of plywood sheathing covered with a roller-applied elastomeric weatherproof coating, then mineral wool insulation board, then furring strips to create an air gap behind the metal and cedar siding.
Photo courtesy of Bundle Design Studio
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Roof lines were angled to optimize the angle for solar energy production from the 9.28-kW photovoltaic electric generation system.
Photo courtesy of Bundle Design Studio
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The harvested rainwater irrigation system provides water to the large vegetable garden.
Photo courtesy of Bundle Design Studio
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The mild and moist Northwest climate contributes to the house achieving both zero-energy and zero-water goals. Rainwater provides all of the home’s domestic water. Passive solar design combines with electricity-producing solar panels and a highly efficient thermal envelope to bring annual utility costs to a calculated -$91 a year. (Yes, that’s negative $91 annually.)
Photo courtesy of Bundle Design Studio
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The majority of the home’s triple-pane windows face south to capture passive solar energy as part of a natural comfort system.
Photo courtesy of Bundle Design Studio
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The home was equipped with a high-efficiency ENERGY STAR refrigerator and dishwasher for energy and water savings.
Photo courtesy of Bundle Design Studio
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The home meets the requirements of the U.S. Environmental Protection Agency’s Indoor airPLUS certification, including the use of structural wood products, primer, paint, cabinets, and flooring that emit no or very few air contaminants.
Photo courtesy of Bundle Design Studio
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A heat recovery ventilator supplies all living spaces with fresh air while exchanging much of the heat or cooling between the incoming and outgoing air.
Photo courtesy of Bundle Design Studio
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The builder tested heat flow with an infrared camera to help ensure a complete continuous thermal blanket and comprehensive draft protection.
Photo courtesy of Bundle Design Studio
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Careful sealing of roof sheathing joints helps to ensure comprehensive draft protection. Blower door testing showed the home achieved a very tight building envelope of only 0.4 air changes per hour at 50 Pascals; that’s 30% tighter than required by the Passive House standard.