What Geothermal is and How it Works

Simply put, geothermal means heat from the ground.

Just like a refrigerator or air conditioner, a geothermal heating system uses a heat pump. The heat pump in an air conditioner cools your home by transferring hot indoor air to the outdoors. The heat pump in a geothermal furnace transfers heat from a different source -- the ground -- sending the warm air inside your home. At just a few feet below the surface, the ground in West Michigan maintains a constant year-round temperature of 49 to 52 degrees, making it a good source of heat.



A mixture of water and small amounts of an environmentally friendly antifreeze solution circulate underground through loops of pipe buried either horizontally or vertically (shown above). The fluid absorbs the heat from the ground, and the geothermal unit extracts the heat using electricity. The extracted heat is distributed throughout your home or business via a standard forced-air system (ductwork). The fluid returns to the ground through the pipe to continue the cycle.

For cooling, the process is simply reversed. The heat pump transfers heat from the building to the ground.

The following brief video explains and shows the entire process in action.

Also see our Frequently Asked Questions.