How to Install a Residential Geothermal System

Dig a trough or pit, between 6 and 20 feet deep. There are many different designs to ground source heat pump layouts, which usually depend on what amount of space you have available. The deeper you go the more consistent the temperatures are year round, but the deeper you go, the more expensive it can become. The key is to get as far below the winter frost line as possible.

Lay loops of geothermal piping in the trough or along the floor of the pit you have dug. Either end of the piping system should be mounted at a convenient location within your basement or your HVAC/furnace room. This is to allow for the connection of both the water pump and the return line, in such manner that glycol will be pumped into one tube, and will flow back from the other tube. Label one pipe "in" and the other "out."

Cover the piping with soil and backfill the pit or trough to permanently bury and insulate the piping.

Fill the piping system with liquid glycol. Glycol holds and transfers heat energy better than water, and will not freeze.

Connect the "out" tube to the inlet nozzle of the heat exchanger element in your furnace using a length of tubing. On the other side (outlet) of the heat exchanger, attach a length of tube from it to a water pump, which will then be connected to the "in" tube of the underground tubing network. The pump will cycle glycol through the piping system underground, where the glycol will absorb the temperature of the ground and then will transfer this temperature to the heat exchanger coil in the furnace. These systems are used to either increase the base heating temperature, or to help heat or cool a heat pump condenser/evaporator, depending on the setup. Basically, these geothermal systems provide you access to a constant temperature that you can tap to help offset cooling costs in summer, and likewise help in winter by providing a warmer-than-ambient-air heat source such as traditional central air systems need to bring a room to a comfortable temperature. A fan in the furnace blows air over the heat exchanger coil, warming or cooling it to the temperature of the glycol from underground.