Imagine living in a house so efficient that the builder guarantees you'll have no energy bills for the first 10 years of ownership.

Such is the promise of Houze Advanced Building Science, a real-estate company in Houston, Texas. The company is building net zero-energy homes, equipped with walls that insulate like a thermos, appliances that sip little electricity and one-of-a-kind power cells.

The houses are some of the first affordable, net energy-producing homes in the United States. And, in Houston, they're moving in to support an otherwise underserved neighbourhood, Independence Heights.

David Goswick, founder and chief executive of Houze, came up with the idea behind the company in 2008, when the US housing market slowed to a standstill. He gathered a team to assess the needs of homebuyers of the future.

"We pushed the pause button and re-evaluated for two years. We realised that the best home investment is in efficiency first," Goswick says. In fact, the "ze" in the company's name refers to "zero energy", he says, because he guarantees the homeowner won't have to make any electricity or gas payments.

The smart thing about Houze is its proprietary residential co-generation power cell, which is about size of an exterior air-conditioning unit. The power cell uses seven different energy sources to power homes – and an entire block. It's fuelled by natural gas and solar, and also captures heat generated onsite for heating and cooling needs.

Because the power cell produces much more energy than each house consumes, it sells excess power back to the grid. Insurance discounts of 40% further cut the costs of ownership.

Independence Heights is one of seven US markets where Houze residences are being constructed. By the end of 2014, the company is planning to establish itself in 50 markets. Construction is under way on as many as 80 homes.

But how energy-efficient are these really? The home energy rating system ranks a home's energy use, with lower numbers representing better efficiency. While a typical new home scores a Home Energy Rating of 100, a Houze home, by comparison, gets 44, which will fall to 0 when in use (because it will supply more energy than it consumes), Goswick says.

Lauran Spanjian, sustainability director for the city of Houston, teamed up with Houze through a public-private partnership. The Independence Heights development is part of a greater plan to position Houston as a pioneer in sustainability and environmental policy.

The city has already become the largest municipal purchaser of green energy in the US, with renewables making up approximately half of its energy mix. It also boasts the third-largest municipal electric-vehicle infrastructure network in the United States and ranks fourth among US cities in buildings that are certified by the Leadership in Energy and Environmental Design, including eight at the platinum level.

Houze is part of a new crop of eco-friendly modular housing companies that include BluHomes, MethodHomes, Living Homes and Connect Homes, among others.

Typically, green residential construction has been much more expensive than conventional home building, and homebuyers have been willing to spend more for their eco-motives. BluHomes, for instance, builds comparably sized, green, pre-fabricated homes for between $590,000 to $885,000, depending on the floor plan. Meanwhile, Houze's Houston homes are priced between $145,000 and $235,000.

Houston's Spanjian says Houze is an attractive building partner, both because its construction satisfies Independence Heights' historic district requirements and because the company is the first green construction she has seen that's affordable to the masses.