The choice of straw bale as an insulating material for the 11 newest homes on Washington State's Lopez Island was an easy one for Sandy Bishop, who as executive director of the Lopez Community Land Trust is overseeing the development. Members of the Trust, which raises money for construction on the 15-mile stretch among the San Juan Islands, foresee a self-sufficient neighborhood whose low- and middle-income residents spin electricity from sunlight, water for washing and flushing from the rain, and warmth from the earth-in the form of straw bale insulation and earthen plasters.
Straw, notes Bishop, is plentiful on the island, and three of the project's primary organizers have built with it before. Plus, the Trust recruited an international collection of college students and young apprentices hoping to break into the building trades to help the future homeowners build their homes, and straw bales are easy for the novices to work with, says Bishop.
"It lends itself well to a lot of hand work," she notes, "and doesn't require as many tools or a high level of skill to make it look good." Even more important, perhaps, is that the 18-inch bales render an insulation value of between R-35 and R-43 in the one- and two-bedroom homes' north and east walls-a sizable jump from the state's required R-21 to R-23.
The Trust's goal for the community-formed as a housing cooperative with 11 detached, single-family homes, plus an office building with two attached rental units-is for each 740- to 1,100-square-foot home to operate at zero net energy within five years.
Straw bales are just one component of that strategy. Blown-in cellulose will give the ceilings an insulated value of R-50, and a bank of double-pane fiberglass windows in each home is designed to catch light and warmth from the sun. The slab-built homes feature a solar hot-water system that is expected to allow residents to avoid using the electric backup water heaters for at least six months a year.
The island, located about 80 miles north of rain-drenched Seattle, sits in a "rain shadow," and the development, in the middle of the island, enjoys a moderate 24 or so inches a year. Still, harvested rainwater will be enough to flush toilets when residents move in early next year, says architect Brian Cloward, an associate with Seattle-based Mithun Architects who helped design the community. The five-year goal for zero energy, says Cloward, will allow the Trust more time to raise money for a 300-foot photovoltaic array, to be installed on the southern end of the neighborhood, where sun exposure is greatest. And the Trust is testing a wind-energy project that could reduce the need for utility-supplied electricity in the future.
The Trust compromised when it came to heating the homes, opting for resistance heating instead of the higher-priced, super-efficient heat pumps that organizers hoped for. It turned out that the nearest heat pump technicians are a ferry ride away in Anacortes, Wash., so repairs could take up to four days if parts weren't in stock.
"We didn't always do the big, sexy stuff," says Cloward, who notes, "There are 1,000 little steps to green."
Indeed, the energy success of the project could depend more on the residents' lifestyles once they move in, he predicts. The Trust will launch a homeowner education project, and each one-story home will be equipped with monitors that show the residents how much water and electricity they're harvesting from the sun and rain-and how much their Energy Star appliances and heating systems are consuming.
"They'll have to work hard to get to zero because they're the biggest piece," says Cloward.
Sharon O'Malley is a freelance writer in College Park, Md.