As Sarah Susanka's Not So Big Showhouse aptly illustrates, we've come a long way from the days when sustainability was unsightly. Thousands of attendees at this year's International Builders' Show in Orlando toured the 2,660-square-foot house, which marries earth-friendly features with innovation and style. Energy efficiency is designed right into its bones. For starters, Susanka gave the house a compact square shape that's easily insulated, with porches and a breezeway and garage radiating around it. Deep overhangs and covered porches modulate Florida's scorching sunlight, and glazing on the east and west walls is kept to a minimum to block the sun's low angles.
“Part of what I try to do when designing a house is to make it a place that inspires you daily, and a place where you'll want to stay for the long haul,” Susanka says. “So daylight becomes an important quality of the interior.” Because direct sunlight can be too harsh in Florida, she created surfaces that bounce it around. Some of the windows are carefully positioned next to side walls that redirect the light. And the bottoms of soffits, which keep ductwork and recessed lights inside the conditioned space, also reflect the light.
Where site-sensitive design reaches its limits, high-performance materials take over. Susanka worked with a small army of building science consultants, including the DOE's Building America teams, to devise optimal energy-efficient strategies for the lowest cost. Under the stucco and fiber cement siding are walls made of R-24 structural insulated panels, covered with a snug weather barrier that breathes. Soy-based spray foam insulation battens down the thermal breaks. And flashing is made of butyl rubber, which bonds better and lasts longer than conventional materials, says building science consultant Steve Easley, SC Easley & Associates, Chicago.
Technology takes the Showhouse's roof and windows to the next level too. The metal roof is treated with a low-E coating that reflects 38 percent of the sun's rays. Spectrally selective windows reflect 70 percent of the sun's heat without filtering the light, and electrochromic skylights can be made opaque with the touch of a button. “You can easily get 40 percent of your cooling load as solar gain through windows, even in parts of the Midwest,” Easley says.
Other energy-conserving technologies include two 16-SEER heat pumps and solar hot water panels. Consultants who are monitoring the house expect heating costs to run $15 a year and cooling costs to average less than $175. For more information on the Not So Big Showhouse and links to consultants, visit www.notsobigshowhouse.com.