In the heating and cooling industry, SEER stands for Seasonal Energy Efficiency Ratio. A SEER rating is the ratio developed when the cooling output of the system over an average cooling season is divided by the total energy used. More simply, SEER is representative of how much energy and money the unit requires to operate effectively over a single year.

A SEER ratio is determined over the course of a full cooling season. The concept is quite simple. The less energy used by the unit to produce the proper amount of cooling, the higher the SEER rating. The SEER ratio is representative of a unit’s maximum efficiency.

Consider the number of miles per gallon (mpg) your vehicle gets when it’s running at its best. Perhaps you get 25 mpg on the highway. City driving, however, produces less efficient fuel usage. The same is true of your air conditioner. A SEER ratio of 21, for example, is the unit’s maximum efficiency and could be lower based on varying conditions.

A higher SEER rating indicates the unit can operate more efficiently in certain conditions. Less energy used can mean greater savings on your monthly utility bill. The amount you save each month will depend, among other variables, on the difference between SEER ratings of your old unit and the new air conditioner.