Because water transfers heat much better than soil, closed loops can also be sunk in lakes or ponds. The coiled pipe can be placed on the bottom of the pond or lake, where it transfers heat to or from the water. A 1/4 to 1/2-acre, 6-foot-deep pond is acceptable. Pond or lake loops often require less excavation than vertical and horizontal loops. Therefore, they are often less expensive to install.

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If land area is limited, closed loops can be inserted into vertical bore holes (as pictured in animated image on previous page). Holes are drilled to a depth of about 125 to 200 feet per ton of unit capacity. U-shaped loops of pipe are inserted into the holes. The holes are then backfilled with a sealing solution.

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If an abundant supply of good, quality well water is available, an open loop system can be installed. A well must have enough capacity to provide adequate water flow for domestic use and the geothermal unit throughout the year. A good way to discharge the water once it has been used must also be available. Ditches, field tile, streams and rivers are the most common discharge areas; however, be sure to check all local codes before selecting a discharge method. If the installation area meets these guidelines, an open loop system can be used. And, since no closed loop is necessary, this installation usually costs less to install and delivers the same high efficiency.

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