When a home-building company called Deltec Homes first launched in 1968, they focused on designing houses that could survive a hurricane. Now one of their main focuses is a different challenge—how to make affordable prefab houses that don’t require any electricity from the grid.

The company has been developing a line of net-zero homes for the last decade. “People 10 years ago didn’t call them net-zero homes,” says Steve Linton, president of Deltec. “But people were building homes that essentially produced all their own energy and asking us to play a big part in that type of project. It’s sort of a long evolution for us.”

Solar Homestead

At first, it was a limited experiment, but the company quickly realized that they could make an entire line of houses. “We kind of had an ‘aha’ moment where we said look, we’ve gotten really good at designing homes this way,” he says. “We really can drive down the energy consumption piece so that the amount of renewable energy required is really affordable—so why not apply it to other architecture?”

The company currently makes nine different models of net-zero houses, each designed to cut out two-thirds of the energy used in a typical house of the same size. The rest is powered by rooftop solar.

“It starts the energy conservation,” Linton says. “We know that ultimately it’s better to save a kilowatt hour of electricity than to produce an extra one.” By making the walls in a factory, for example, it’s possible to include gaskets that make them more airtight than if they were built piece by piece on site. The company also works with clients to plan a design based on their land—how the sun can warm and light the house, and how trees can keep it cool. Windows are chosen to either let in heat from the sun or keep it out, based on the location.

Rhododendron

The company also helps save energy by encouraging people to buy smaller homes. “The average home size today in America is twice what it was in the 1950s,” he says. “It’s gone from a 1,000-square-foot home average to over a 2,500-square-foot home average. That, at the end of the day, is really driving energy consumption. . . . We’ve got to find a way to start changing that dynamic for new homes if we’re really going to have an impact on the overall sustainability of homes.”

Though the line includes larger houses for larger families—up to around 2,100 square feet—it also sells models that are only 800 square feet.