Jason and Kelly Joseph, 32 and 31

Grand Rapids, Mich.

Jason and Kelly Joseph don't drive a hybrid car. They don't shop exclusively in the natural foods aisle. And they don't lose sleep worrying about global warming.

But their house, a 2,800-square-foot Craftsman near Grand Rapids, would make the Environmental Defense Fund proud.

The walls are insulated with draft-stopping foam; the floors are covered in wood from a sustainable forest; and the rooms are decked out with nontoxic paint, just to name a few of its earth-friendly features.

The Josephs weren't planning to go green. But when their builder described the benefits - lower heating and cooling bills and better indoor-air quality - they agreed that it was worth adding $10,000 to their total tab.

"If you're building a house as a lifelong investment, it just seems like the right thing to do," says Jason. And only a year after the house was completed, many of the upgrades are already beginning to pay for themselves, he notes. "Our friends' energy bills were almost double ours last winter."

Would going green work for you?