Skip to main content.
Family of Four Relaxing on Couch

Geothermal Energy

Geothermal energy (derived from the root words "geo", meaning earth and "thermal" meaning heat) is generated from heat energy contained deep within the earth. By taking advantage of the warmth of the earth, both utilities and homeowners can utilize a renewable source of energy that can be used to produce power or heat and cool a home efficiently.

Get savings from the ground up with a geothermal heat pump

Although homeowners do not drill wells into the earth to find steam and hot water, geothermal heat pumps provide a technology that utilizes the near-constant ground temperature in order to heat and cool your home. Rebates are often available for residential customers who convert from gas to a geothermal heat pump.

Get more helpful information on renewables from one of our Energy Experts by calling 800-268-9644.

How It Works

Everyone knows it’s cooler underground in the summer and warmer underground in the winter. Geothermal systems take advantage of the earth’s constant temperatures to provide the highest efficiency available today. Special plastic piping is buried below the ground’s surface which allows heat to be transferred to and from the earth. Water is simply re-circulated to and from the underground piping where it is warmed by the earth in the winter and cooled by the earth in the summer. Rebates are often available for residential customers who convert from gas to a geothermal heat pump.

Benefits of Geothermal Energy

Energy savings - Customers can cut heating and cooling costs in half. Add optional hot water units to save even more.

Energy efficiency - Because the ground or water temperatures are much more constant year-round, geothermal heat pumps operate more efficiently.

Lower cost - lower operating, maintenance, and life cycle cost.

Comfort - Constant temperatures are easier to maintain with Geothermal systems. Provide greater comfort than other heating and cooling systems.

Low maintenance - Fewer mechanical components and no outdoor equipment make repairs less likely.

Durability - Closed-loop systems lie underground, protected from harsh weather.

Quiet - No outdoor compressor noise. Enjoy your patio, pool or deck without disturbing mechanical noises.

Aesthetics - no visible outdoor unit.

Environmentally friendly - Near-constant ground temperatures make it possible to use the earth's natural thermal qualities to provide energy to heat or cool your home without burning fuel and polluting the environment.

What is a geothermal heat pump?

An electrically powered device that uses the near-constant temperature of the earth to heat and cool your home. Geothermal heat pumps operate like traditional air-to-air heat pumps, moving heat rather than creating heat. However, they use the ground or water as a heat source, rather than outside air, creating an air-to-liquid heat exchange.
The geothermal system connects an indoor heat pump with a matrix of outdoor buried plastic piping. The system circulates water through these underground pipes where it is warmed by the earth in the winter and cooled by the earth in the summer. This natural heating and cooling action, in conjunction with heat pump technology, can maintain indoor spaces at a constant, comfortable temperature without burning fossil fuels.

What components make up a Geothermal system?

The heat pump unit, the underground closed-loop system and the ductwork.

What is a closed-loop system?

A continuous loop of special buried plastic pipe connected to the indoor heat pump. Unlike an open-loop system that draws water from a well, a closed-loop system recirculates the same water under pressure, functioning as a heat exchanger with the earth. Because the water is sealed inside the piping, it remains pure, requiring less filtering and less potential maintenance.

How long will the pipe last?

High-density polyethylene pipe properly heat fused should last over 50 years. This material is unaffected by chemicals normally found in soil and has good conducting properties. PVC pipe should not be used.

Can anyone install the system?

Do-it-yourself installation is not recommended. It is best to employ IGSPHA or manufacturer certified technicians and contractors to install your Geothermal system. Retrofits in buildings with existing ductwork are typically easy to install. Consult your local dealer to determine any modifications that might be necessary.

What if I need heating but have no ventilation?

Geothermal uses no combustion and therefore needs no outside venting.

How effective is this underground system?

Conceived in the 1940s, refined heat pump designs and improved pipe materials make Geothermal systems the most efficient heating and cooling options available today.

Will the buried pipes affect my lawn or landscape?

After installation, closed-loop piping has no effect on grass, trees and shrubs. Installation requires displacement of some turf which can be restored with grass seed or sod.

Can a Geothermal system also heat water for my house?

Yes. Using a device called a "desuperheater," Geothermal systems can preheat tank water to save up to 50% on water heating bills.
For more on Geothermal heating and cooling systems, visit these websites:

GeoExchange Heat Pump Consortium
Electric Power Research Institute