What Are Geothermal Heat Pumps?
Geothermal (or Water Source) Heat Pumps have been long recognized by the U.S. Department of Energy (DOE) and the Environmental Protection Agency (EPA) as the “most energy efficient and environmentally friendly” systems available. This is a worthy commendation yet the first question for a savvy home owner is often, “what does this mean to me in a practical sense?”
Geothermal heat pump systems have two energy ratings, the Coefficient of Performance (COP) and an Energy Efficiency Ratio (EER).
Standard air-source heat pumps also have EER ratings making this an easily comparable factor. A good EER for an air-source heat pump would be 12.5 EER (that which qualifies the system for federal and state energy efficiency tax credits). Geothermal heat pumps require a 14.1 EER for a tax credit but often greatly exceed this requirement with ratings up to 27.0 EER! This means the geothermal heat pump would be twice as efficient as the air source heat pump in cooling mode.
The COP is the most straight-forward standard of measurement in that it measures the amount of energy used compared to the amount of energy delivered to your home in heating & cooling. Minimum COP for geothermal tax credits is 3.4 yet many two-stage geothermal heat pumps achieve ratings up to 4.8 COP when properly designed. This means that for every $1 of energy used by the heat pump, you are effectively receiving $4.80 of heating/cooling energy into your home. Another way to look at it is that the geothermal heat pump is 480% more efficient!
As you can see in the graph below, the majority of your monthly energy costs go towards heating & cooling as well as hot water. Geothermal heat pumps take a massive bite out of these monthly bills. An experience geothermal contractor will be able provide a payback schedule to help determine if the typically higher installation cost makes sense.
Compare this to a standard gas furnace that measures energy efficiency by an Annual Fuel Utilization Ratio (AFUE) and can only achieve up to 98% efficiency in burning fossil fuels. That’s a significant difference! Air-source heat pumps will, as a rule of thumb, achieve 200 – 300% efficiencies (although Carrier’s Greenspeed heat pump is closer to 350%), still approximately 30% less than a geothermal heat pump.
A guide to Energy Efficiency Ratings
AFUE (annual fuel utilization efficiency)
SEER (seasonal energy efficiency ratio)
(energy efficiency ratio)
(heating seasonal performance factor)
(coefficient of performance)
Air Source Heat Pumps
7.5 – 13
Geothermal Heat Pumps
3.0 – 5.0
Here is a photo of a typical loop field installation for the geothermal system and the single-piece indoor unit.
Specialty Heating & Cooling has been installing geothermal heat pumps since 1990, one of the first contractors to become experts in the Portland Oregon area. We have installed several hundred throughout the area and have learned through the school of hard knocks exactly what is needed for geothermal heat pump systems to perform as promised!
Contact us at 503-862-2050 to learn more or set up a no-obligation consultation.
See the map below for a large sampling of Specialty Heating & Cooling geothermal system installations since 1990!