Geothermal Heat Pumps

Efficient and environmentally friendly, geothermal heat pumps use the stable, even temperature of the earth to heat and cool your home.

A Down-to-Earth, Smart Energy Choice

A geothermal heat pump takes advantage of the earth’s constant temperature to provide highly efficient heating and cooling. In the winter, fluid circulating in underground pipes carries the earth’s heat to your home, where it is concentrated to provide heating. In the summer, the process is reversed and heat from your home is carried back to the earth through the pipes to provide cooling.

According to studies, ENERGY STAR®-certified geothermal heat pumps can reduce energy costs by 20 to 70 percent. Approximately 70 percent of the energy used in a geothermal heat pump system is renewable energy from the ground. The systems use a small amount of electricity to operate the heat pump, ground loop pump, and distribution fan or pump.

A geothermal heat pump is a reliable, low-maintenance, and environmentally friendly heating and cooling choice. It operates safely and quietly, with no combustion, direct emissions or exposed outdoor equipment, such as a fuel tank. Because it is mechanically simple and all exterior equipment is below ground, protected from the weather, maintenance costs are often lower than other heating and cooling systems.

How We Help

We make it affordable to install a geothermal heat pump system with rebates of $750 per ton or $1,500 per ton when replacing oil or propane, rebate not to exceed $15,000 per home. Provided by the Connecticut Energy Efficiency Fund for qualifying systems.

Heat and cool your home from the ground up. It’s a down-to-earth, smart energy choice.

Call 877.WISE.USE (877.947.3873) for more information. 


How a Geothermal Heat Pump Works

A few feet below the earth’s surface, the ground temperature remains fairly stable through the year, ranging from 45 degrees in the North to 70 degrees in the South. Ground temperatures, like those in a cave, are warmer than the air above in the winter and cooler than the air in the summer. A geothermal heat pump taps these conditions, carrying energy through a series of fluid-filled copper or plastic pipes installed underground. This allows the geothermal heat pump to provide space heating and cooling. Some systems can also heat water.

A geothermal system consists of three elements:

  • A closed loop circulates fluid through an underground field. The loop is enclosed in vertical and/or horizontal trenches.
  • Single or multiple pumps, fans and compressors provide heating and cooling.
  • A distribution system, typically ductwork, carries air throughout the home to maintain an even temperature.

How to Apply

Existing Homes: If you haven’t invested in making your home energy efficient, now is the time. To be eligible for a geothermal heat pump incentive, homes must meet energy efficiency standards. Learn how to upgrade your home with help from the Home Energy Solutions program.

New Construction: For new residential construction geothermal measures, all applicants must participate in the Residential New Construction program.


Eligibility is determined based on the existing heating system. Rebates are not to exceed $15,000 per home.

  • Existing customers with electric or natural gas heating systems will be eligible for $750 per ton.
  • Existing customers with oil or propane heating systems will be eligible for $1,500 per ton.

When your application is approved, your UI Program Administrator will send you a stamped Connecticut Energy Efficiency Fund Residential Geothermal Performance Incentive Final Application.


Choose a geothermal contractor for your installation. Although you are free to use any geothermal contractor, feel free to choose a contractor from the list on

Please find the rebate application here.

Save time and apply online.


Who is Eligible and System Requirements

UI residential electric service customers are eligible for incentives for the installation of a geothermal closed loop or direct expansion, packaged or matched coil/split* including water to water-designed types up to six tons per unit.


Eligible Systems are closed loop water to water, water to air and direct expansion ground source heat pumps. They must be a matched assembly that is a model combination that is listed in the AHRI Directory of Certified Equipment at When multiple sections are installed simultaneously, a matched assembly shall include the air handler, furnace, coil or other component that is used to determine the rating according to ARI/ISO/ASHRAE 13256-1/2 or ARI 370 published current standards. Water and DX to Water Systems must meet the utility-derived efficiency goal comparison. System(s) must be ENERGY STAR® certified and meet 2021 efficiency requirements as listed at

  • GLHP – Closed Loop Water to Air 17.1 EER1 / 3.6 COP2 Minimum
  • DX – Direct Expansion Refrigerant 16.0 EER / 3.6 COP
  • W to W – Water to Water 16.1 EER / 3.1 COP

A list of ENERGY STAR-certified geothermal equipment can be found on the ENERGY STAR website.

UI residential electric service customers are eligible for incentives for the installation of a geothermal closed loop or direct expansion, packaged or matched coil/split* including water to water-designed types up to six tons per unit.

Geothermal equipment must be a closed loop or direct expansion type and ENERGY STAR® certified in order to be eligible for a rebate.

Field testing must be done under appropriate test conditions.

  • AHRI/ISO/ASHRAE Standard 13256-1 closed loop systems
  • AHRI/ISO/ASHRAE Standard 870 for DX systems

The Connecticut Energy Efficiency Fund rebate for qualifying units is $750 or $1500 per AHRI reported cooling ton in 1/2 ton increments up to a maximum of $15,000 per home. Rebate amount determined by existing heating system fuel.


Geothermal FAQs

Geothermal heat pumps take advantage of the earth’s constant temperature to provide efficient heating and cooling. A few feet beneath the earth’s surface, the temperature of the ground remains fairly stable year-round, ranging from 450F (northern latitudes) to 700F (deep south). Like a cave, this ground temperature is warmer than the air above it during the winter and cooler than the air during the summer. Geothermal heat pumps take advantage of these conditions by exchanging heat with the earth. This allows the GHP to heat, cool, and if so equipped, supply the home with hot water.

A GHP system collects the earth’s natural heat through a fluid-filled series or loop of pipes made of copper or plastic that is installed below the surface of the ground. The pipes can also be submersed in a body of water such as a lake or pond. Fluid circulating in the pipes carries the earth’s heat to the home. In the winter, an electric compressor and heat exchanger concentrates the earth’s heat and releases it into the home at a higher temperature and then distributes it through ductwork or pipes. In the summer, the process is reversed so that excess heat is drawn from the home, expelled to the pipes and absorbed by the earth.

Geothermal heat pumps are efficient because they are using electricity to remove heat from the ground rather than converting electricity directly to heat. During the summer, geothermal heat pumps take advantage of the cool earth to provide efficient air conditioning. Geothermal heat pumps can also use the waste heat from air conditioning to provide “free” hot water heating in the summer.


Because geothermal systems do not rely on fossil fuels to operate, they do not rely upon combustion. Therefore, there are no direct emissions, fuel tanks, or chimneys. With few moving parts, these systems are reliable and have low maintenance costs.


Geothermal Heat Pumps have a higher installed cost compare to traditional systems due to the ground coupling. However, the low-operating cost can save money over the life of the system.


Geothermal systems do not provide free heat. Rather, they use electricity to operate single or multiple pumps, fans and compressors. Depending on the size and design of the system, the electricity consumption can be significant. However, since the systems are taking advantage of the earth’s constant temperature, they are an efficient heating system and may save anywhere from 20 percent to 70 percent compared to a conventional heating and cooling system.


Geothermal systems are extremely safe. There isn’t any exposed outdoor equipment, and geothermal units do not rely on combustion so there isn’t a need for fuel tanks or gas lines.


Units are extremely quiet. Since there isn’t any visible outdoor equipment, outdoor activities are not disrupted by the cycling of a fan.

The most common type of geothermal system relies upon a closed loop which circulates fluid or refrigerant through the ground. These fields are either vertical and/or consist of horizontal trenches, and can run several hundred feet or more.


Geothermal Heat Pumps have the ability to provide both heating and cooling with the simple flick of a switch on the indoor thermostat. In winter, heat pumps extract heat from the ground and distribute it throughout the home. In summer, the process is reversed and heated air is drawn from the home and allowed to be absorbed into the ground.


Information on tax credits can be found at: or contact your tax professional.