Ground Source Heat Pump Basics
Ground source heat pumps (GSHPs) utilize the relatively constant temperature of the earth as a heat source in cold months and as a heat sink in warm months. They consist of an electric heat pump and a water pump in a building as well as underground coils of plastic tubing. The water pump circulates water (or an antifreeze solution) through the underground tubing, where it collects or dumps heat. The underground tubing can be run in coils either horizontally at least six feet underground or vertically 250 feet or more underground in a “loop field”. Horizontal loop fields require more space but can be less expensive to install than vertical loop fields. After exchanging heat with the ground, the liquid in the tubing gets further heated or cooled by the heat pump. The liquid can then be used to condition air blown through ducts or as a heat source for radiant floor systems.
Ground Source Heat Pumps vs. Air Source Heat Pumps
GSHPs can be considerably more efficient than air source heat pumps (ASHPs), don’t necessarily require backup heat, and can heat either air or water to run through the home. On the other hand, they can be significantly more expensive and land-intensive to install than ASHPs even with incentives. Like ASHPs, the success of the system depends largely on the quality of the installation. If using electricity from Colorado’s grid to power the pump, greenhouse gas emissions from GSHPs are comparable to emissions associated with a combination of high efficiency natural gas furnaces and conventional air conditioners.
Is A Ground Source Heat Pump Right For You?
A ground source heat pump may be right for you if:
- You wish to both heat and cool your building
- You have enough land area for a horizontal system or are willing to pay more for a vertical system
- Your land area for the loop isn’t rocky
- You currently use expensive fuels like electricity or propane to heat your building
- You have access to an experienced installer with a proven track record of success
- You are prepared to pay significantly more for a GSHP than a conventional heating and cooling system in order to recoup operating costs over time