Geothermal 101

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Article reprinted with permission from The Geothermal Exchange Organization (GEO), a non-profit trade association,


Geothermal Heating and Cooling Works in Harmony with the Earth

Geothermal Heat Pumps are self-contained units that efficiently heat and cool homes and commercial buildings while providing hot water. They use standard electronic thermostats and duct systems, making them appropriate for retrofits of standard heating, ventilation and air conditioning (HVAC) systems. Geothermal Heat Pumps can be sized to heat and cool any building in any climate.

Geothermal Heat Pumps quietly and reliably harness the renewable energy generated by the sun that is stored in the ground near the Earth’s surface. They make significant contributions to a cleaner environment by saving energy, cutting fossil fuel use, and reducing carbon emissions.

graphic of using the earth for heating and cooling

The Earth is a source of heat during the winter months. . .

graphic of heating methods

… and an efficient place to reject heat during the summer months.

photo of using the ground for cooling

Ground Loops Connect Buildings to the Earth’s Heat

Unlike conventional heating and air conditions systems that use the outside air to absorb and release heat, Geothermal Heat Pumps transfer heat from and to the ground. They do that through closed loops of plastic pipes buried either horizontally or vertically in the ground below the frost line where the temperature is consistently between 40° to 80° F depending on where you live. Called ground loops, the pipes are sealed tight, and connected to the geothermal heating and cooling system inside the building. Water circulates through the underground pipes of the ground loop.

graphic of ground loops

During the summer months in cooling mode, unwanted heat indoors is transferred outside through the water in the pipes for cooling by the earth. The cool water is then circulated to the geothermal system indoors to provide efficient air conditioning. During the winter months, the process is reversed in heating mode. The earth heats the water circulating through the pipes, which is transferred to the geothermal system to provide indoor space heating. Hot water can also be provided for little or no additional monthly energy cost.

Geothermal Heat Pumps Can Slash Energy Use in Buildings

Geothermal heat pumps effectively address one of the biggest consumers of U.S. energy — buildings. Indeed, buildings dominate our nation’s energy use, devouring over half of our electricity and natural gas. More than 70 percent of average energy demand for a typical single family home is to meet heating and cooling (thermal) needs. With a geothermal heat pump, that energy use can be cut by 40 percent to 70 percent, reaping significant savings on electricity and natural gas utility bills.

Conventional Heating and Air Conditioning

conventional heating and cooling graphic

Over 70 percent of the energy consumed by a typical single-family detached home is used to meet thermal loads.

Geothermal Heat Pump System

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Total residential site energy consumption is cut in half.

Geothermal Heat Pumps can cut carbon emissions from building energy use by 50 percent.

Building energy use emits 43 percent of total U.S. carbon emission.

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Geothermal Heat Pumps cut carbon emissions from buildings

CO2 emissions graphic

Energy Savings Offer Fast Payback of Installation Costs

Though there is a higher “first cost” for Geothermal Heat Pump systems associated with excavation or drilling for installation of ground loops, energy savings can quickly make up the difference in system cost compared to installation of conventional systems. Energy savings “payback” for typical residential Geothermal Heat Pump installations compared to standard heating and air conditioning equipment is usually 4 to 7 years, and even less time than that with federal, state and utility rebates.

Geothermal Heat Pumps harness on-site renewable energy from the Earth and are a readily available technology that can be used everywhere. Geothermal Heat Pumps are truly a “50-state” renewable technology that provide large energy savings and complementary environmental benefits to both new building construction and retrofits for older structures.

Date of Publication: 
September, 2016