Hot Rocks
Heating your house from the ground up
By Milly Hart

Beneath the Adirondack Park's arctic-zone plants, glacier-carved mountains and dark forests it's always 50 degrees.

Even in February, that's the temperature of the earth under northern New York, from the frost line to about 2,000 feet below, and it's stable throughout the year.

Home and business owners looking for an alternative to heating with fossil fuels are tapping into the underground. Solar power isn't an option for a lot of park residents because trees and mountains (not to mention clouds) block the rays. A few homesteaders have gone off the grid with wind power, but giant turbines haven't been permitted inside the Adirondack Park yet because of concern they might harm birds and bats, as well as the scenery.

If granite underlays your building site, as it does much of this region, you may have to drill a little deeper to tap the earth's warmth, but it's there. Two major new institutions, Tannery Pond Community Center, which opened in North Creek in 2002, and the expanded Arts Center in Old Forge, due to open next year, both chose geothermal energy to heat and cool their facilities.

Marty DeVit, owner of Thermal Associates, in Glens Falls, installed Tannery Pond's system and dozens of others in the southeastern Adirondacks over the past 24 years. Most of his sales have been clinched by economics: The earth's heat is free, and geothermal systems make up the comparatively high cost of installation in fuel savings over anywhere from three to 18 years, varying with how deep pipes must be sunk, the size of a building and other factors. "It all depends on what kind of real estate you have," DeVit says. Tannery Pond estimates an annual saving of $24,000 in energy costs, for a three-year payback.

The earth's heat is also nonpolluting, and a new wave of environmentally aware buyers are motivated by a desire to minimize carbon emissions, he adds. For them, saving money on fuel oil (which was hovering near two dollars a gallon at press time) is a bonus, as is the equipment's long life expectancy, built-in water-heating and the elimination of boilers.

"It would nicely fit in with our personal dreams—a small, easy-to-care–for home that is not greedily consuming. So, comfort and absolution at the same time," says Susan Moody, who with her husband, Alan Brown, is planning to build four energy-efficient town houses on the Saranac River, in Saranac Lake. "Saving the planet is going to require a change in our energy infrastructure and a change in our attitudes. It is not going to have one solution. Geothermal energy is one that seems to make sense in many ways. If we all took a step, any step, forward, we might see a trend that could turn the tide before it is too late."

Moody and Brown are studying an estimate of $35,000 per 2,000-square-foot unit. Five loops of pipe would be sunk 400 feet beneath each home. The depth is needed because the lot is too small to lay horizontal pipes, and the tubes must have ample surface area to absorb the earth's temperature.

Geothermal isn't the answer for every home, although DeVit says even a middle-income family living in a bungalow on a small village lot could consider it. Get an on-site assessment of your property from an expert to determine what kind of system would work best. Any geothermal system requires three things: 1. A place to lower pipes into the earth (in a horizontal pattern about 10 feet down if you have a large property or sandy/clay soils, or straight down if your building sits on a small lot or rock). 2. A heat pump, to exchange cool water for warm inside and outside the house. 3. A heat distribution system like those inside any house (radiant floor heat or hot-air ducts, for example).

Ground-source heat pumps are not like furnaces, according to Natural Home Heating, by Greg Pahl. Inside a sheet–metal box usually small enough to fit in a closet, a cold liquid refrigerant absorbs heat from the ground. The liquid evaporates as it warms, becoming a gas, he writes. "This refrigerant gas [contained in coils] then passes through a compressor, where it is pressurized, raising its temperature to 160 degrees. The heated gas then circulates through another heat exchanger, where heat is removed from the gas and transferred to water or air that is circulated into your home." Or vice versa to cool a house. The pump runs on electricity, so unless you install solar or ternative-source power, geothermal is not a grid-free technology.

Contrary to popular belief, rock is a good base for the tubes, say DeVit and John Manning, a Skaneateles-based contractor who has worked on the Akwesasne Mohawk reservation and Fort Drum Army base. Holes drilled in granite are unlikely to shift. Also contrary to popular belief, DeVit and Manning say the technology makes sense for cold climates. Sunbelt dwellers who use the earth to cool their homes get a faster payback (using 70 percent less energy than conventional air-conditioning), but in the long run the numbers still add up.

The saving Alan Brown anticipates, compared to an oil or propane system, is 40 to 60 percent, so he expects to make up his investment in 10 or so years. "This is not great financially but, if you believe fossil fuels have nowhere to go but up, it begins to look better," he says.