Frequently Asked Questions



What is a geothermal heating and cooling system?
A geothermal heating and cooling system (also called geo-exchange or ground-source heat pump system) is one that uses heat stored in the ground to heat or cool a home or building.

These systems work by circulating a fluid through a well or a trench in the ground and “capturing” the heat of the shallow earth. The fluid then transfers the heat into a structure where it is distributed by an air-blower or through hot water piping. In the summer, these systems can commonly be operated in reverse, capturing the heat from the structure and subsequently transferring it to the earth, thereby cooling the structure during hotter weather.

What are the different options for geothermal systems in New Hampshire?
There are essentially two types of geothermal systems used in New Hampshire. The most common type is referred to as an “open-loop” geothermal system, and includes a groundwater well (or wells), a water well pump, piping and a compressor [heat pump] installed in the structure. In this type of system, groundwater is used as the heat transfer fluid and is pumped out of the well, and circulated through the structure’s heat pump where heat is extracted from or injected into the water. Then the heated/cooled water is re-injected into the same groundwater well from which it was withdrawn or a separate well dedicated to re-injection.

The less frequent type used in the state is a “closed-loop” geothermal system. In these systems, an antifreeze solution or refrigerant is circulated through a continuous loop of plastic or copper pipe, which is installed in either a drilled well, horizontal trench or the bottom of a surface water body. Similar to the above, heat is either injected into or extracted from the antifreeze/refrigerant by the heat pump; after which, the fluid is re-circulated back into the loop of pipe installed in the ground.

What are the advantages of a geothermal system?
Savings - Geothermal systems can cut your home or business hearing an cooling costs by 50 percent and provide hot water for free or at a substantial savings.

Durability - Ground source heat pumps last longer than conventional systems because they are protected from harsh outdoor weather. The heat pump unit is housed indoors and the loop is underground.

Low Maintenance - Geothermal systems have fewer mechanical components, making them more reliable and less prone to failure. The ground loop has an expected life of over 50 years and requires no maintenance.

Cleanliness - Geothermal systems work toward the preservation of the environment by minimizing present environmental problems like acid rain, air pollution and the destruction of the ozone layer.

Low Noise - Ground source heat pumps have no exposed, noisy outside units. The unit operates quietly to satisfy your needs without disturbing you or your neighbors. Conservation - Geothermal systems work with the environment by using the earth's moderate ground temperature to heat your home or business in the winter and to cool it in the summer.

Health - Geothermal systems keep indoor air cleaner and free of pollens, outdoor pollutants, mold spores and other allergens.