Green Energy: The Basics of Geothermal Systems

Mary Butler

Despite their high cost, geothermal systems are gaining in popularity, as more people discover the benefits of using the earth's unwavering underground temperature to heat and cool their homes.

Sure, installing a geothermal system can cost between $10,000 and $25,000--and sometimes more. But the U.S. government offers a 30 percent credit with no price limit, and depending on your energy needs, a system can pay for itself in less than 10 years. Equipment has improved, costs have come down and last summer's high oil prices all have given residential builders more incentive to consider the systems.

Doing the Math
One Georgia couple, who plan to spend about $32,000 on a system currently in construction, told the Atlanta Journal-Constitution their energy savings should be about $60 greater than their loan payment on the system, and that over 20 years, they could save $26,000 in energy costs. And, depending on your state's laws, you also may not have to pay higher property taxes if the system boosts the value of your home. Not a bad investment at all, especially if you're planning to live in your home for many years to come.

Cool Science
Here's how it works. Deep wells are dug to house the system's looping pipes. Geothermal pipes can be buried either vertically, where space isn't available, or horizontally, if there's a large yard or vacant piece of land. During the winter, water in the pipes move the earth's heat to the house, where it is absorbed by a refrigerant, compressed to a higher temperature and blown into rooms. During the summer, heat is taken from the house and sent underground. Pipes are generally buried at least 6 feet underground, where the temperature is constant.

While electricity is still needed to run geothermal systems, you can bypass the need to depend on the grid by using solar panels or even a small wind turbine to generate power for it.

Right now, fewer than 1 percent of households use geothermal, the U.S. Department of Energy estimates. But that may change as the Obama administration encourages geothermal, among other alternative energy sources, as part of its efforts to wean the nation from it's dependence on fossil fuels. Adding a geothermal system isn't just for new construction, either. Your home simply needs ducts through which the warmed or chilled air can flow.

About the Author:

Colorado-based freelancer Mary Butler writes about homes and gardens.

About the Author
Mary Butler is a Boulder, Colorado based writer and editor, who spends much of her free time remodeling an old house.

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