TC Legend Homes built this small 400-square-foot apartment over an existing garage behind a larger home in Seattle, Washington, to the performance criteria of the DOE Zero Energy Ready Home (ZERH) program.
The south-facing shed roof of this home is optimally angled for solar energy production should the homeowner decide to install solar panels in the future; however, even without solar panels, the home cut utility costs $454 compared to a similar-sized home built to the 2012 energy code. The home is expected to have utility bills of about $824 per year or $69 per month.
Fiber cement siding on the walls and ice-and-water shield under the standing seam metal roof help provide long-lasting protection for the home’s exterior.
The home’s walls and roof are constructed using structurally insulated panels (SIPs) with an insulation value of R-29 in the walls and R-42 in the roof. The SIPs are taped at the seams and the cement board siding is caulked at the seams to properly air-seal the home.
For healthy indoor air quality, only low-VOC paints and finishes were used. A 24-hour timered exhaust fan exhausts stale air and brings in fresh air through passive inlets embedded under the slab.
Low-flow plumbing fixtures, ENERY STAR appliances, and advanced LED lighting add to water and energy savings.
Low-e, triple-paned vinyl-framed windows and slider doors provide ample daylighting without sacrificing thermal comfort.
Low-flow fixtures reduce water use so a 30-gallon electric water heater can supply all of the hot water the apartment needs.