Below are some of the more commonly used HVAC ratings and a basic description of what they mean:
SEER: The Seasonal Energy Efficiency Ratio is a measure of the cooling efficiency of your central air conditioner or heat pump. It is the amount of cooling that an air conditioner (or heat pump) delivers per watt of electricity used. The higher the SEER number the better the system is at converting electricity into cooling your home. The industry minimum SEER is currently 14.00.
HSPF: The Heating Seasonal Performance Factor is a measure of the heating efficiency of a central heat pump. The higher the HSPF number the better the heat pump converts electricity to heat for heating your home. HSPF is a measure of a heat pump’s energy efficiency over one heating season. Heat pump industry minimum HSPF is currently 8.2.
AFUE: The Annual Fuel Utilization Efficiency tells how efficiently a gas or oil furnace converts fuel into heat. An AFUE of 80% means that 80% of the fuel is used to heat your home while 20% is wasted. AFUE is limited in that it only refers to the unit’s fuel usage and not its electrical consumption. The industry minimum AFUE is currently 80%.
COP: The Coefficient Of Performance is a measure of heating capacity (in Btu/h) at standard heating conditions divided by its electrical input (in watts). The higher the COP, the more efficient the unit is at converting electricity into heat. This rating is commonly used for geothermal heat pumps where the source of heat (ground) is a stable temperature year round so does not require “seasonal” averaging like SEER or HSPF. The industry minimum COP for geothermal heat pumps is currently 3.6 on closed loop systems and 4.1 on open loop systems (water-to-air).
EER: The Energy Efficiency Ratio is a measure of cooling capacity (in Btu/h) divided by its electrical input (in watts). The higher the EER, the more efficient the unit is at converting electricity into cooling. EER is not seasonally averaged (see SEER above). The industry minimum EER for geothermal heat pumps is currently 17.1 on closed loop systems and 21.1 on open loop systems (water-to-air).