Ground Source Heat Pumps: Clean, Cost-effective and Quiet

Considering the potential cost savings, it’s surprising that more people aren’t familiar with ground source heat pumps (also known as geothermal heat pumps or “Geoexchange” systems), which capture solar energy that’s absorbed by the earth and stored a few feet underground.

Commonly used for heating and cooling and to meet some hot water requirements, they’re suitable for any size structure—from homes to large commercial buildings—and may be installed during initial construction or retrofit.

In a closed loop system, high density polyethylene piping is buried underground (horizontally at 4-6 feet deep or vertically at 100-400 feet deep, depending on the site) and filled with a solution of water and antifreeze.  During winter, this liquid absorbs geothermal heat and carries it into the building; in summer, it absorbs heat from the building and pushes it into the earth.  Open loop systems are similar, but need an outside source of water and an appropriate place to discharge waste. In both cases, the main unit is about the size of a typical furnace.

Installation is relatively straightforward, but requires specific knowledge and equipment and should be done by a certified professional.  To achieve optimal performance, for example, it’s important to configure and size the system correctly, use the correct type and amount of refrigerant, seal and insulate ducts in attics and crawlspaces, and ensure proper air flow.

Ground source heat pumps cost more to install than traditional heating and cooling systems (though prices are coming down), but the investment is recovered within three to five years. According to the US Environmental Protection Agency, they’re about 40% more energy efficient than air source heat pumps, 48% more than natural gas furnaces and 75% more than oil furnaces. This translates into utility bills that are 30-50% lower than conventional technologies.

Among their other benefits, the EPA says that “greenhouse gas emissions associated with the use of geothermal heat pumps are 50-60% lower than those from standard air-source heat pumps.” They’re also quieter than other systems, offer low maintenance costs, and are known to deliver extremely high consumer satisfaction.

For more information or to find a qualified geothermal specialist, please visit:

US Department of Energy
International Ground Source Heat Pump Association
Geothermal Heat Pump Consortium