The owners of this certified Passive House in Ann Arbor, Mich., cherish their nearly five-acre property, which backs up to a wildlife-rich estuary. Seeing its natural beauty from the house was a top priority. They wanted most of the glazing on the north side in order to optimize views of the prairie fields and to ensure privacy on the other sides of the house, which are subject to potential eyesores from future development. That orientation would limit exposure to desirable solar gain and heat energy. The solution was to incorporate a thermal storage and delivery system in the form of three Trombe walls. Of course, high-performance building materials and mechanical systems contributed to the house’s tight, energy-efficient envelope, which measures 0.6ACH50, but there were a few low-tech strategies at play, too.
Architecture as problem-solver
According to Michael Klement, principal of Architectural Resource, the design concept for the single-story ranch house was “21st-century Craftsman Prairie”—after Frank Lloyd Wright’s Prairie homes, which had their heyday in the 1920s. It is visually distinct for its long, extended horizontal lines meant to emulate the plains, and the two-story center section, which houses the guest bedrooms. The hip roof is notably detailed with 5-1/2-ft.-deep overhangs with a pronounced knife-edge. The overhangs are key. During the hot summer months, the walls (and interiors) are fully shaded; come late December, low winter sun is able to reach inside the house thanks to upwardly angled soffits.
The approach is from the southeast, which means the…