For nearly 25 years, Michael Sykes has been honing his design of an energy-efficient wood home that heats and cools itself. The History Channel has honored his efforts by awarding the Youngsville builder the $25,000 grand prize in its Modern Marvels Invent Now Challenge.

Sykes, an N.C. State University mechanical engineering graduate, calls his invention the Enertia House. Homes are built with Southern yellow pine, which Sykes says is best at maintaining a constant temperature. His business, Enertia Building Systems, sells kits that the home-owner then has built. For details and to see the homes, go to his Web site at enertia.com. Staff writer Vicki Parker talked to Sykes about his business and his award.

Q: How did you get started?

A: I started building log homes to help pay my way through school. I enjoyed it, so I stayed with it. In 1973, I built one for a friend in Wake Forest, and I just wondered why it was more energy efficient. I started to tweak it. ... I wanted it to be totally energy efficient.

In 1986, I came up with the idea of using a small atmosphere between the walls to put energy into the wood. The sunspace connects to the attic and the basement, forming a convection loop. The sun comes in through the south windows, heating the air, which rises and travels around the space. The wood absorbs energy during the day and at night the wood radiates the energy to the occupants. The key is that the walls are massive solid wood, not 2-by-4's packed with insulation.

Q: Is the Enertia House easy to build?

A: Yes. The house is put together with wood blocks called glulams [glued wooden blocks]. All you need is an electric drill, and just connect the numbered blocks, and you've got a house. ... It's like a big Lego set.

Q: Some people think using wood to build homes is bad. How do you respond?

A: That's not true. The Southern yellow pines we use are harvested on tree farms. When the lumber company harvests the trees, more trees are planted to replace them. None of these trees are cut from original forests.

Q: How many Enertia Houses have you sold and where?

A: I've built 80 homes in 25 states. I've built six homes in North Carolina.

Q: Who are your typical customers?

A: All types. But I have a lot of retired clients who don't want to be worried about paying oil and electric bills. They want the house to take care of them, not the other way around.