Geothermal Heat Pump Resource
Teaching you how to make your home more comfortable!



Residential Geothermal Furnace System

How Does A Geothermal Home Heating System Work?

  The basic elements of a geothermal heat pump (GHP) system include a:

  • Ground loop — system of fluid-filled plastic pipes buried in the shallow ground, or placed in a body of water, near the building
  • Heat pump — removes heat from the fluid in the pipes, concentrates it, and transfers it to the building (for cooling, this process is reversed)
  • Air delivery system — conventional ductwork used to distribute heated or cooled air throughout the building.
   Residential Geothermal Furnace

Simply put, a GHP works much like the refrigerator in your kitchen, with the addition of a few extra valves that allow heat-exchange fluid to follow two different paths: one for heating and one for cooling. The GHP takes heat from a warm area and exchanges the heat to a cooler area, and vice versa. The beauty of such a system is that it can be used for both heating and cooling—doing away with the need for separate furnace and air-conditioning systems—and for free hot water heating during the summer months.

Geothermal heat pumps use electricity to heat and cool, just like a conventional heat pump. However, unlike a conventional heat pump, GHPs use the relatively constant temperature of the shallow Earth as a source of heat in the winter and as a repository for heat in the summer.

In the winter, the fluid passing through the underground (or underwater) loops of piping is warmed by the Earth's heat. The collected heat is extracted and concentrated by the heat pump, and distributed through the building's ductwork.

To cool the building in the summer, this process is reversed — the heat pump moves heat from the indoor air into the underground loops, where it is transferred to the relatively cooler ground. The heat removed from the indoor air during the summer can also be used to produce some of your hot water, or to heat swimming pools, instead of transferring it to the ground.

 Types of Residential Geothermal Furnace Systems
Geothermal heat pumps are generally classified as "closed-loop" or "open-loop" systems based on the type of ground loop that they use:
  • Closed-loop systems. Closed-loop systems circulate a solution of water and antifreeze through a series of sealed loops of piping. The loops can be installed in the ground horizontally or vertically, or they can be placed in a body of water, such as a pond.
  • Open-loop systems. Open-loop systems circulate water drawn from a ground or surface water source. Once the heat has been transferred into or out of the water, the water is returned to a well or surface discharge (instead of being recirculated through the system).  Open-loop systems are not recommended for residential use.


Heating Water for Buildings and Pools with GHPs

  • Buildings. Most geothermal heat pumps sold today are equipped with a "desuperheater" to meet up to half of your home or business's hot water needs. Desuperheaters provide the greatest benefit during the summer, when hot water is produced using the excess heat removed from the building during the cooling process. In the winter, desuperheaters can also reduce your hot water bills by preheating water. Desuperheaters are standard on some units, optional on others. Stand-alone systems that will heat water on demand (instead of only when space heating/cooling takes place) can also be purchased.
  • Pools. Pool heating using a GHP is effective in warm climates, where a great deal of excess heat is produced during the space cooling season. You will need to purchase a separate "water-to-water" heat exchanger to heat your pool.




Are you building a home and looking for a custom, energy efficient house plan?  Visit my home design site at for more information.

 phillip rye custom home design