What is a Geothermal Heat Pump?

By Avery Dietzen on 01/14/2021

Geothermal heat pumps continue to make a name for themselves as an energy efficient and environmentally friendly heat source. They don’t rely on electricity to generate heat, which leads to less greenhouse gas emissions as well as energy savings for you!

But how do geothermal heat pumps warm a home? A few feet below the surface, the ground remains between 45-70 degrees Fahrenheit. Depending on the location, that temperature remains the same all year long.

Geothermal heat pumps utilize underground heat, exchanging heat energy with the ground to heat or cool a home.

How do geothermal heat pumps work?

Geothermal, or ground-source, heat pumps attach to ground loops. These ground loops install in trenches, underground, or underwater. A liquid refrigerant circulates within the ground loops, absorbing heat energy as it passes through. The refrigerant collects the heat, evaporates into a gas, and carries the heat inside the heat pump system. The gas condenses back into a liquid, which releases the heat energy. This allows the indoor unit to then distribute that heat back to your home.

The same process works in reverse to cool your home, pulling heat from the room and depositing it into the ground.

Geothermal heat pumps can function in warm and cool climates. However, if you live in a colder climate, we recommend using supplemental heating as well.

How efficient are geothermal heat pumps?

While many heating systems require electricity to create or generate heat, geothermal heat pumps transfer heat instead. They only require electricity to power them, which reduces the amount of energy you use, as well as your energy bill.

You can check the efficiency of geothermal heat pump with the Energy Efficiency Rating (EER) and Coefficient of Performance (COP) rating. The EER rating will tell you how efficiently the heat pump cools. The COP rating will tell you how efficiently it heats. The higher the rating, the more efficiently the heat pump performs.

Types of Geothermal Heat Pumps

You have options when it comes to geothermal heat pumps, including ground loop orientation and heat exchange method.

Closed vs. Open Loop Systems

Closed loop systems continuously circulate the same refrigerant within ground loops. As a closed system, nothing goes in or out except for heat energy.

Open loop systems use water from a nearby clean water source as a refrigerant. Unlike closed loop systems, they only use this water once. Open loop systems may return the water through a discharge well or drainage ditch. They may also direct it back to a pond or lake.

Not all municipalities allow open-loop systems as they can disturb or contaminate the water source.

Closed Ground Loop Orientations


Horizontal closed loop systems require deep trenches to install the loops into. According to the U.S. Department of Energy, they serve as cost-effective options for residential installations.


The vertical closed loop system works best in areas with shallow soil or areas with strict landscape requirements. Instead of trenching, the ground loops install vertically in holes, using a U-Bend to form a loop.


Pond/Lake closed loop systems exchange heat energy with a body of water instead of the ground. As a closed loop system, water from the pond or lake does not enter the system, only heat energy.

Though they function as a lower cost alternative, pond/lake systems must meet strict volume, depth, and quality requirements to install.

Dual-Source Heat Pumps

You can find dual-source heat pumps that combine geothermal and air-source heat pump technology. They function as a more affordable alternative to only geothermal heat pumps. While not quite as energy efficient as geothermal heat pumps, they provide more energy efficiency than air-source heat pumps.


Heat and cool your home in an energy efficient and eco-friendly way with a geothermal heat pump system. Find geothermal heat pumps at HomElectrical!


Related blogs:

Environmentally Friendly Heating and Cooling Options

Go Green With Outdoor Lighting!

Should I Switch to a Ductless Heating and Cooling System?

Panasonic Mini Split Air Conditioner