Air Heat Pump Vs. Geothermal

Geothermal heat pumps and air-source heat pumps are two of the most popular heat pump technologies for heating a home. The major differences in the technologies are in how efficient they are and what they use as an energy source.

Geothermal

Geothermal heat pumps use a ground heat exchanger to exchange heat with the earth just a few feet below the Earth's surface. Ground temperature remains fairly constant year-round, which means geothermal heat pumps can heat a home with efficiencies as high as 300 percent to 600 percent on cold nights, compared to air-source systems, which can reach 175 percent to 250 percent efficiency. Geothermal units are more costly to install than air-source units.

Air-Source

Air-source heat pumps use a refrigeration system to exchange air from the outdoors to either heat or cool a home. While air-source heat pumps have become more efficient, they are generally not recommended for areas with long periods of sub-freezing temperatures because they can't heat cost-effectively, according to the U.S. Department of Energy.

Dual Source

A dual source heat pump combines the technology of geothermal and air-source heat pumps. While they are less costly to install, dual source heat pumps are more efficient than air-source systems, but less efficient than geothermal units.

References

• U.S. Department of Energy: Energy Savers; Geothermal Heat Pumps.
• EnergyStar.gov: Heat Pumps, Air-Source.
• U.S. Department of Energy: Energy Savers; Air-Source Heat Pumps.