Geothermal Heat Pumps, Explained

woman holds plant

Geothermal heat pumps use the earth as a heat source in the winter and as a heat storage source in the summer. Typically consisting of an indoor heat pump and a buried system of pipes called a ground loop and/or a well system, these systems utilize the constant temperature of the earth to provide “free” energy.

This method provides extremely efficient heating or cooling all year long in virtually any climate without harming the environment. Plus, the ground loop components can last up to 50 years!

How Geothermal Heat Pumps Work

Geothermal heat pumps exchange heat between the house and the earth to provide heating or cooling. In the winter, a geothermal heat pump system absorbs heat from the earth and transfer it indoors to heat the home. In the summer, it works the other way around: the system pulls the heat from inside and transfers it underground to cool off the house.

Fun fact: the temperature underground does not fluctuate as dramatically as outdoor temperatures do. Thanks to the mass of the earth, ground and water temperatures four to eight feet below ground stay relatively constant throughout the year. On average, this constant earth temperature is higher than winter temperatures and lower than summer temperatures, making geothermal a reliable method for seasonal heating and cooling.

Types of Loop Systems

There are several options out there for geothermal loop systems, depending on the climate, land area, and application.

Talk to your Bosch representative to discuss the best solution for you. Below are the most common types:

pond loop


This tends to be the least expensive application. Pond/lake loop systems work well in areas with a large body of water and where boating, fishing, or other activities do not pose a risk to the system. Pond loops can also provide advantages to marine life.

vertical ground loop

Vertical Ground

The most common system, vertical group loops are a great option for areas with limited space. To create the loops, holes are drilled into the earth and then a pair of High Density Polyethylene pipes, connected by a “U” bend at the bottom, are inserted into each hole. The bore holes are then sealed with an environmentally safe grout material to enhance the transfer heat to and from the earth, as well as to protect the subterranean environments. The underground pipes are connected together and run neatly into the home, where they link to a geothermal heat pump.

horizontal ground

Horizontal Ground

Even though horizontal ground loops are often less expensive to install, they need more surface area. Rather than drilling, trenchers are excavators are used to dig at least 4 to 6 feet deep. Loop variations ranging from single pipes to slinky style are laid at the bottom of the excavation. Then, the piping is joined together so it can run into the home and be connected to a geothermal heat pump. As a final step, the excavation is backfilled and returned to its original condition.

well loop

Well Water

For predominantly warm weather climates, well water systems are often your best choice. First, a pair of boreholes is drilled: one as the source well and one as the injection well. Then, the water is pumped from the aquifer through the geothermal heat pumps and injected back into the aquifer with no chemical change.

Go Green to Save Green

Although geothermal systems do cost a little more to install, the return on investment can be rapid. Geothermal systems help homeowners cut down on their utility bills and reduce energy consumption by 25% to 70%, depending on the region and installation comparisons.

Homeowners who install geothermal systems can also qualify for tax credits. The United States Tax Code was revised to reinstate the tax credit available to consumers related to the installation of geothermal heat pumps retroactively. As a result, consumers who purchased qualified systems in 2020, 2021, and 2022 can take a one-time tax credit equal to 26% of the investment in the geothermal system, including installation costs, without a cap. In 2023, the one-time tax credit will be reduced to 22%.

Additionally, many areas offer local incentives for utilities, counties, or states. Visit the U.S. Department of Energy’s “Database of State Incentives for Renewable Energy” (DSIRE) at to learn how saving energy can help save you money in the long run.

Bosch Geothermal Heat Pumps

Bosch geothermal systems are among the longest lasting, most efficient technologies available for heating and cooling. Browse our residential and commercial portfolio: