Geothermal Heating & Cooling

Geothermal heat pumps (also known as Ground Source Heat Pumps or a GSHP) heat and cool buildings using the constant year-round temperature of the ground. A GSHP is highly efficient, runs using a refrigeration cycle, and operates using the same scientific principles as your household fridge. During heating season, a GSHP extracts heat from the ground and transfers it to a building. In the cooling season, a GSHP runs in reverse; it extracts heat from the building and rejects it into the ground. Contrary to popular belief, a GSHP works well in cold climates, does not require deep earth high temperature thermal energy, nor is it out of the price range of homeowners due to many incentive and rebate programs. A GSHP can save homeowners money in the long run, can reduce their carbon footprint significantly, and can free them of the need to combust fossil fuels.

Geothermal Heat Pump Infographics

Learn about Geothermal Heat Pumps

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A GSHP system is made up of three main components: two heat exchangers and a referigerant loop.

1. Ground Loop: The ground heat exchanger, also commonly called a ground loop, is the mechanism by which a GSHP system exchanges thermal energy with the ground. The ground loop is a series of underground pipes that circulate a fluid with a pump. The fluid transfers and transports the thermal energy. Ground loops may be open or closed loops, depending on the layout of the land and energy loads. Furthermore, there are different configurations of open and closed loops. For a detailed comparison of open and ground loops, see Infographic 5, 6 and Resource 2.

2. Distribution System: The distribution system removes heat from a building in cooling mode and emits heat to a building in heating mode. GSHP systems are compatible with forced air and hydronic systems. For more details on distribution systems see Resource 1.

3. Heat Pump: The Heat Pump is the loop of mechanical devices that make up a basic refrigerant cycle to transfer heat to and from the ground loop fluid to heat, cool, and produce domestic hot water for a building. Depending on the size of the house, a GSHP system may utilize a 3-ton, 4-ton or even a 5-ton heat pump. For more information about heat pump sizing and compressor staging see Resource 1 and Resource 3.

Cost of a Geothermal Heat Pump

The cost of a geothermal heat pump depends on multiple factors; every situation is different. The initial cost of the system and well drilling may be high but there are numerous rebates, incentives, and tax credits available to help offset this cost. For example, homeowners can now receive a federal tax incentive equal to 30% the cost of a qualified geothermal heat pump system. With proper sizing and analysis, most systems will have a reasonable payback period (See example of a homeowner’s geothermal system with $25,000 initial cost). For more details about system features, check out our pricing guide in Resource 4.

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