Zero-Energy Homes Becoming More Popular

In Arizona, it's the steady sun that's beating soaring energy costs.

Jose and Marciala Reyes built a zero-energy home in Tucson, where solar power produces heat, air conditioning and even hot water. How much are the Reyes' monthly energy bills?

"We pay between, on the average, $20 to $28," said Jose Reyes, a retired businessman.

Sometimes, their bills are as low as $5 a month -- a savings of around $250 compared to others in their area.

Zero-energy homes are springing up in developments across the West. Built with three times as many panels as a conventional solar-powered home, the Reyes sometimes sell power back to the local utility. Then, their electric meter actually runs backward.

"We will save enough energy in this development to power 10 times that many homes that are built under normal condition," said John Miller, a Tucson-area builder.

The Reyeses spent $28,000 more than they would have on a normal home, but with smaller bills and tax rebates, that cost will be recouped in five years.

Energy from Underground

Builders say solar power is perfect for the climate in Arizona, with its 340 days of sun each year. But in places like Oxford, Ohio, there is seldom any sun during the long winter, so residents are finding other alternatives to heating their homes.

Some are finding energy savings in a hole in the ground -- that's where contractors are building geothermal power units. Loops of water-filled pipe are buried below the frost line. From there, they pass the Earth's internal heat through a special furnace.

Contractor Bill Spade has never been busier installing the $15,000 units.

"When you go from doing a couple of jobs a year to doing, like, four jobs a month, it's a big change," Spade said.

There's a simple reason more people are interested: Geothermal heat will cost about $1,100 over the next year, compared to more than $3,000 for natural gas.

Back in Arizona, the Reyeses are convinced their $28,000 cost is a good investment.

"If we had put money in the bank … would I be getting $200, $250 a month in return? I don't think so," Reyes said.

And Reyes said unlike oil, the cost of the sun remains constant.

ABC News' Bob Jamieson filed this report for "World News Tonight."