[IMAGE: Residential GeoExchange Systems (Cooling Mode)]

"Switching from oil-based to electricity-based heating was simplified by the fact that the local electric cooperative already had her on an interruptible rate. Like most of the local co-ops, this coop had the right to interrupt the power supply for the home's electric heating, cooling, and hot water by radio signal during peak-load conditions to reduce peak demand. As compensation for this periodic inconvenience, the company cuts the price of electricity during peak periods to specific interruptible mechanicals in half."

"With a geothermal heat pump, the client can now take 75 percent of the energy from a free renewable in the earth. Therefore, 75 percent of the homeowner's energy is free, while the other 25 percent is at this reduced rate--roughly 4-cents-per kilowatt. While it doesn't happen everywhere, this isn't an unusual program among the Wisconsin coops."

HORIZONTAL AND VERTICAL LOOPS

[IMAGE: Residential GeoExchange Systems (Heating Mode)]

Geothermal heat pumps use the natural heat storage capacity of the earth or ground water to provide energy-efficient heating and cooling. These graphics show how the system works to make the home more comfortable, regardless of the season. Graphics courtesy of the Geothermal Heat Pump Consortium.

"If you have the space, horizontal loops are usually less expensive than vertical loops. The client was in an excellent location for horizontal loops--a low area that was just cropland. It was also adjacent to a low-lying wet area, and the pipes were laid in sand saturated with water. We dug a horizontal trench 12 feet wide, 8 feet deep, and 300 feet long. We put in 600 feet of 3/4 inch polyethylene pipe per ton for a four-ton system. We installed 2,400 feet of pipe and closed the trench back up in one day."

"The loop was almost half the total price tag, around $5,500 to $6,000. It's less expensive than a vertical loop and usually easier to schedule. A vertical loop is at least another couple thousand dollars, since we have to call in a driller. Drillers are very busy with the increasing demand due to high fuel costs. It seems like there are a few more companies getting into it, and I think in the next few years, demand is going to expand that market. However, if you have the right piece of property with adequate open space, you can usually do a horizontal loop and not require a driller."

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