Geothermal provides long-term, cost-saving, sustainable energy for homeowners.
This illustration demonstrates how energy is pulled from the earth and circulated through a home.
Sunrise Alternative Energy has designed and installed geothermal heating and air conditioning systems for more than 25 years now. “One of the biggest misconceptions about geothermal is that it is a new technology,” says Bob Willis, owner of the Edmond, Okla.-based company. And this efficient alternative energy source is not just for new construction. “We retrofit geothermal into many existing homes,” adds Willis.
Geothermal heat pumps, also referred to as ground source heat pumps (GSHPs) are similar to ordinary heat pumps, but instead of using heat found in outside air, the system relies on the free energy of “the greatest solar collector in existence,” the earth, to provide heating, air conditioning and even hot water. Even though summers can be blazing hot and winters frigid, at six feet underground temperatures typically range from a stable 45 to 75 degrees.
In winter, natural heat from the earth is collected as fluid circulates through a series of underground pipes, called a loop. Then, using an electrically driven compressor and a heat exchanger, the heat is released inside the home. During the summer, the loop draws excess heat from the house where it is absorbed into the earth.
“Geothermal reduces electricity use, shifts high use to off-peak loads and creates American jobs. It’s a win-win-win,” explains Willis. Approximately 70 percent of the energy used in a geothermal heat pump system is renewable energy from the ground.
Geothermal systems can be installed in virtually any size residence and on almost any size lot, with pipes under lawns, driveways and even the house. Underground horizontal loops, the most common and cost efficient system, are used when the size of the lot is large enough. If the yard is too small or the soil is too rocky, a vertical loop plunging several hundred feet deep is utilized.
Initially installing a geothermal HVAC system is expensive, but consumers can expect at least 30 to 40 percent lower energy bills, according to estimates from the U.S. Environmental Protection Agency, who also includes geothermal heat pumps in the EnergyStar program. The systems are rated to last around 25 years.
“Geothermal is approximately 30 percent more up-front than a conventional system, but after the 30 percent federal tax credit and various available rebates, the initial cost is paid back fairly soon,” says Willis. Check the Database of State Incentives for Renewables and Efficiency (www.dsireusa.org) for the list of rebates and tax credits available throughout Oklahoma.
Oklahoma happens to be the epicenter of geothermal research and development since the International Ground Source Heat Pump Association (IGSHPA) World Headquarters is located on the Oklahoma State University campus in Stillwater.
Geothermal heat pump systems are usually not do-it-yourself projects. You’ll want the professional expertise from an accredited installer familiar with IGSHPA procedures to calculate a home’s heat load and design a system based upon various factors including soil condition, lot size and the home’s overall square footage. Retrofit projects typically can utilize current ductwork while new construction installations should be coordinated with the builder.
Eight years after Willis installed a geothermal system in Edmond homeowner Veta Roberts’ spacious, five-bedroom home, she continues to be thrilled with the results. “It’s quiet, low maintenance, and our monthly utility bill is considerably less than if we had conventional heat and air conditioning,” she says.