Anyone who has retreated to a cold basement on a hot day knows the concept is as old, quite literally, as the hills. Beneath the Earth's surface, the temperature is constant. By tapping that, homeowners with geothermal systems can cool their homes, or provide heat.
A geothermal system circulates a water solution through pipes that are buried beneath the home, yard or, if there is a body of water close by, underwater.
In the winter, the fluid carried by the system is warmer than surface air. In the summer, it is cooler. The home's ventilation system distributes air, warmed or cooled by the fluid, throughout the house.
A geothermal system costs more to install than a conventional heating/venting/air conditioning (HVAC) system, but pumping the warm/cool air through the house uses less electricity than does a typical heating or cooling system. So it can yield long-term energy savings which, in turn, can save money. The system doesn't burn fossil fuels, which makes it the right choice for many environmentalists.
Such systems "are more popular in some areas than in others," says Mike Bell, spokesman for the National Association of Home Builders' (NAHB) green building committee.
"Where they are used more often, there are more HVAC contractors who do them or utilities that encourage them through incentive programs."
This means geothermal systems are more prevalent in homes in Oklahoma, Texas, Wisconsin, New Hampshire and Colorado. In Illinois, "geothermal" is, at least on the residential side of real estate, largely still a foreign term outside "green" circles.
For Rita Angelini of Prospect Heights, the investment was worthwhile.
"My husband wanted to find out how to make this house energy-efficient long-term, so he learned about it," saysAngelini. She and her husband, Norman Riess, tore down the house they owned on the same lot and built their current house in 2005. Built to accommodate their disabled daughter, it has 5,000 square feet plus a room with an indoor therapy pool that is heated to 90 degrees year-round.
Angelini says their electric bill runs $500 a month.
"We can't compare that to our old, smaller house," she says. "But we can compare it to a friend's house that is half the size of ours and also has an indoor, heated pool, but costs $600 to $700 a month for a conventional HVAC system."
Before ComEd's recent price increases, Angelini had figured their payback period for the additional cost of the geothermal system would be five years. Now, she says, it will be longer.
"It is still worth it because we are staying in this house," says Angelini. "My daughter will live here for her lifetime. We'd do it again, despite the increase."
"For me, it was a no-brainer," says Doreen Schweitzer of Naperville, who installed a geothermal system in the 5000-square-foot house she built in 2006. "I feel a responsibility for our environment, and this is a greener way than using a furnace and air conditioner."
Schweitzer's last bill for electricity, which she buys from the city of Naperville, was $200 for two months. "That was during that hot weather this summer, and we were very comfortable," she says.
Schweitzer says she had initially figured it would take her seven to ten years to pay back the added cost of the geothermal system, but increased electrical rates will extend her payback period, she says.
"I'd still do it again," says Schweitzer.
To help cover the cost of a geothermal system, some homeowners employ "energy-efficient mortgages" (EEMs) that allow larger loans based anticipated lower utility bills. (The homeowner pays less money monthly for utilities, meaning he or she can afford more for his monthly mortgage bill.) For more information about this, visithttp://www.resnet.us .
Geothermal systems are more often chosen by high-end home buyers, says Bell. "Then, the buyer works with the architect and custom builder to choose green systems. At the production [home-building] end, the builder doesn't take the time or make the investment," he says.
Jan Mostrum of Evanston, though, isn't as pleased. She and her husband, Terry, tore down their house and built a new, 4,200-square-foot house with a geothermal system.
The good news, says Mostrum, is the system eliminated the placement of a noisy and unsightly compressor on the side of their house, which would have been close to the neighbor's house. The bad news, though, is that this year's Commonwealth Edison price increase sent their electric bill through the roof.
"We pay $650 to $750 a month for our electric bill now, not counting a gas bill of $50 to $150 for our dryer, stove, oven and fireplace starters," says Mostrum. "At this point, it will take us 17 years to recoup the money."
Geothermal systems seem to making more inroads into the multi-family than single-family market here.
Chicago-based Dynaprop Development Corp. is using a geothermal system to heat and cool its upcoming Eco18 project in the South Loop. The building will include one-, two- and three-bedroom condominiums, plus commercial space. In addition to its geothermal system, Eco18 will use solar panels to heat water and include water-saving amenities such as low-flow showerheads and dual-flush toilets. Part of the building will have a green roof.
The additional cost of using a geothermal system, says Dynaprop president Rick Turner, will be built in to the sales price of the units. But, he adds, the owners should see lower electrical bills.
Geothermal was one of the selling points for Carrie and Brian Mattei, who bought a townhouse at Church Street Village in Evanston. She is an environmental engineer and he is an architect, so geothermal systems are familiar to them.
The $367,000 price tag of the Matteis'three-bedroom townhouse beat those of its competitors, says Carrie, so lower electrical bills generated by the geothermal system will be a bonus.
"This is attracting educated buyers who want green features," says Walter Kihm, CEO of Cyrus Homes, of the Church Street Village homeowners.
Homeowners with geothermal systems urge others considering them to find knowledgeable installers because not every HVAC contractor understands these systems. To find an installer who is trained and certified, contact the International Ground Source Heat Pump Association at Oklahoma State University (see sidebar).
"If your HVAC contractor says, 'Oh, sure, I can do this,' that's not good enough," says Bell. "He may not understand it or may not have done it before."
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For more information about geothermal systems, visit these Web sites:
http://www.igshpa.okstate.edu . International Ground Source Heat Pump Association
http://www.geoexchange.org . Geothermal Heat Pump Consortium
http://www.resnet.us . Residential Energy Service Network