Air Source Heat Pumps
Central heat pumps operate much like a central air conditioner except that they can reverse the cycle in the winter to deliver heat to the house. They are much more energy-efficient than electric furnaces; however, conventional air-source heat pumps are only appropriate in mild or warm climates. Because heat pumps provide both heating and cooling, they have two efficiency ratings: seasonal energy efficiency ratio (SEER), and heating system performance factor (HSPF). When selecting a new heat pump, look for the following:
High Seasonal Efficiency
ACEEE recommends SEER at least 14.5 and HSPF in the range of 9.0. Heat pumps meeting these performance criteria can be found by running a search in the ARI/CEE HVAC Directory.
Compatibility
Depending on the indoor unit installed, SEER and HSPF can vary significantly within the ranges of efficiency provided for the outdoor condensing units. Make sure all of the components of the system are designed to work together. Check with your contractor or visit the Air-Conditioning and Refrigeration Institute to see the specific SEER and HSPF values for the combination you are considering.