Green living: Sustainable design is Big Thunder's big payoff

Green living: A $40,000 investment in sustainable design pays off in seven years at Big Thunder

This was the year the dream finally came completely true at "Big Thunder," the house that John Sagebiel and Mary Cablk built.

Seven years after moving in, they figure the $40,000 they invested in sustainable architecture and solar energy has finally been recouped in the savings they've had in heating, cooling, and powering their two-story, 3,200-square-foot home outside Reno, Nev.

"People see this," Mr. Sagebiel says of the desert-hued exposed-timber-frame "Big Thunder," "and say that must have cost you a fortune."

"Are you kidding me?" he laughs. "This is making me a fortune! It's expensive only if you look at the day you install it. It's just a matter of how you do the math."

Sagebiel is an environmental chemist who studies air pollution, and his wife, Ms. Cablk, is a wildlife ecologist specializing in desert tortoises. Both work at the University of Nevada's Desert Research Institute in Reno. So when they set out to build their house on a stretch of beautiful high desert, there was no question it would rely on clean power and sustainable architecture.

The home's array of stand-alone photovoltaic solar panels generates more energy than the couple needs, so they send clean energy back to the grid. The utility company essentially gives them "credits," which Sagebiel plans to use in the future to power an electric car. And they avoid the $2,000-a-year electric bill they'd otherwise pay.

The biggest "bang for the buck," he says, is the solar thermal system. It heats the home as it pumps warm water through an eight-inch-thick concrete floor. The system, which has seven temperature zones, cost $10,000, and saves them $6,000 in propane heating per year. "If you heat 200,000 pounds of concrete, it stays hot for a long time," Sagebiel says. "You have this enormous mass that's warm, so rather than heating the air in the house, which dissipates quickly, we're heating the house itself."

Strategically placed windows and overhangs also help: Eaves are wide enough to block overhead summer sun but narrow enough to let in low-in-the-sky winter rays.

They collect gray water from the sink and shower to irrigate the garden. And the house frame is built largely from recycled timbers, including from a demolished grain elevator. Between saving money, helping the environment, and creating lovely surroundings that blend with the desert outside, Sagebiel sees their house as a manifestation of their personalities and life goals.

"Environmentally, it's so many things, from the local to the global," he says. "This home is an expression of who we are and what we want, financially, aesthetically, and environmentally. And it has to just be a joy. If it's not, what are we doing it for?"