[多项选择]Joe Harberg became an energy-efficiency guru because he didn’t know the first thing about energy efficiency. In 2003 he was constructing a new home in Dallas and wanted to work with his builder to make the place as environmentally friendly as possible. But neither Harberg nor his designer had any training in how to turn an ordinary house green, and they found few resources to help them. "It was so frustrating," says Harberg, 46, a Dallas-based entrepreneur.
Relying principally on the Internet, Harberg—who previously had worked as a marketing expert and real estate developer—did manage to build an energy-efficient home. He boasts that his electricity bills are regularly 50% less than those of similar homes in his neighborhood, and the entrepreneur in him saw an opportunity. Lots of people worry about global warming, not to mention the soaring costs of powering a home, but they don’t know what to do about it. Working with his brother-in-law Josh Stern, Harberg helped launch what wou