SEER (Seasonal Energy Efficiency Ratio)
SEER stands for Seasonal Energy Efficiency Ratio. It is used as a measurement of how efficient your heat pump is, which is found by dividing the amount of cooling the heat pump does, in BTUs, by the total amount of electric energy used, in kilo-watt hours, to run the heat pump. This means that the SEER measures how efficient your heat pump will be at its maximum efficiency. The higher the SEER rating, the more efficient your heat pump is. Most modern appliances have a SEER between 13 and 21.
For an appliance to be eligible for the EnergyStar label it needs to have a SEER of at least 14.5. It is important to note that the given SEER rating for an appliance may not actually be true in your home. There are a variety of factors that can keep the unit from performing at maximum efficiency such as: the unit is not sized correctly for the home, the duct system is inefficient in distributing the conditioned air, there is insufficient insulation to keep the conditioned air in, and other variables around the home or environment. However, a unit with a higher SEER value will still be more efficient than a unit with a lower SEER value.