In Joe Turner's ultra-efficient house in Salt Lake City, the windows never feel cold nor do the concrete floors even though they don't have in-floor heating.

"The whole house is the same temperature," says Turner, a computer programmer who built it with his partner, Rebecca Guymon. "It's nice not to have these drafty spots. The house is also super quiet."

The secret? Their house -- picked as "This Week's Green House" -- is among the first in the United States to be certified by the Passive House Institute, an Illinois-based firm that verifies whether homes meet strict efficiency standards.

Thousands of passive homes, which use up to 90% less energy than other houses, have been built in Europe, especially Germany.

Yet fewer than a dozen exist in the United States, according to Turner's architect David Brach, who is fully certified by the institute. The institute lists fewer than 100 approved consultants nationwide.

Passive homes are very well-insulated and almost airtight, so the little energy they need can come from passive solar gain, solar panels or tiny HVAC equipment. To ensure good air circulation, they use mechanical ventilation.

Turner and Guymon had lived on the property for years in an old home that they initially considered remodeling. Instead, in December 2007, they began working with Brach to design a new passive house.

They moved into a basement apartment four blocks away during construction, which begin last April. "We'd walk by every day," recalls Turner, often wishing the project would go faster. In December, they moved into the 3,000-square-foot house, twice the size of their old one.

Their house, including design, cost about $175 per square foot. He says they spent $30,000 on their 2.2-kilowatt solar array but got $12,000 back in federal and state credits.

Aside from the solar panels, Turner says the house cost about 16% more than a regular new house. He says the bulk of that was because of its fiberglass Serious Windows, which are perhaps the most efficient ones made in the United States. He expects the payback will come in about 11 years.

Their energy bill for March, which was quite cold in Salt Lake City, was $40 and it's on track to be $10 this month, Turner says. In the summer, he expects to sell power back to the grid, receiving a credit from the utility that he'll then use in the winter for heating.

"It's probably not net zero but close," says Brach, referring to whether the house produces as much energy as it uses.

Turner says they also did the simple stuff, such as using Energy Star appliances, dual-flush toilets and, instead of a gas cooktop, an induction one.

He says he knew his house would be energy-efficient but he never realized just how comfortable and quiet it would be. He adds: "I love it."