How Geothermal Energy Systems Work In Homes

Written by Andy Stauffer

July 25

geothermal energy diagram

One of the alternative energy systems we build with, in addition to solar systems, is a geothermal energy system, most often used in tandem with an in-floor radiant heat system, which heats an entire home. A commonly-asked question we get with geothermal, though, is “How does it work?” While we’ll let the experts explain it in technical detail, here is a great diagram and description that shows the steps involved.

The Six Stages of a Geothermal Energy System


Step 1: Ground loops filled with fluid absorb heat in the winter, and release heat in the summer.

Step 2: The evaporator transfers heat from the ground loops to the refrigerant fluid circulating in the system.

Step 3: The compressor increases the pressure on the fluid to raise its temperature.

Step 4: The desuperheater takes some of the excess heat and routes it to the hot water heater.

Step 5: A reversing valve lets the heat pump switch directions to either heat or cool the building.

Step 6: The expansion valve lowers the fluid’s pressure and temperature so it flows toward the evaporator, and the cycle starts all over again.

Want to learn more? Here are a few great articles that more about the technical side, including information on the return on investment (ROI) and associated costs:

Among the many benefits of using a geothermal energy system to heat your home is the fact that there are often tax credits available. For example, there’s a federal tax credit available for up to 30% of the cost of the system (for more info, check out this great article in the San Francisco Chronicle about tax credits). If you’re interested in a geothermal energy system, feel free to contact us and we’d be happy to explain more about how it all works, and help determine if geothermal energy is a good fit for your home.

If you’re interested in seeing examples of homes we’ve built that have geothermal systems, you can view the Coyne Residence, or the Thies Residence. These are just two of many homes we’ve built that are run partially using geothermal energy. If you want to see a geothermal energy system in action, just contact us and we’d can arrange for you to visit one of our homes to see how it works and discuss associated costs.


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