When consumers are looking to purchase a new air conditioner, they should consider a few different factors in the decision making process. One factor that should play a major role in the purchase of an air conditioner is the energy efficiency of the unit. The energy efficiency of the air conditioner is an important deciding factor because this will determine the cost of operating the machine.

What is the SEER rating?

The most common measure used to demonstrate the overall efficiency of an air conditioner is the Seasonal Energy Efficiency Ratio, which is commonly known as the SEER rating. With this system the unit is tested for the BTU output and that is weighed against the operational electricity across a range of temperatures. Depending on how many BTU are produced per kilowatt hour of electricity across the range of tests, the air conditioner will be assigned a numeric SEER rating. With a SEER rating, a higher number represents better energy efficiency. Units that are sold in the United States must have a SEER rating of at least 13, but some models have a rating that goes all the way up to 23.


When an air conditioner is tested for its SEER rating there are few factors that are considered. These factors are the temperatures that the system will be subjected to during the cooling season, the BTU output per season and the total kilowatt hours of electricity that are consumed by the air conditioner during the cooling season.

During the SEER test, the unit will be set to operate for a set amount of hours per day with temperatures varying to represent the realistic operation of the air conditioner. When the complete season of testing is completed, the total amount of BTU that the air conditioner has produced will be compared to the total amount of electricity consumed. This will allow the testers to determine the average BTU production of the unit per kilowatt hour over the course of the season.


The SEER rating of an air conditioner should be an important consideration for any consumer. An air conditioner that has a SEER rating that is a few points higher than the next can save the owner a few thousand dollars over the life of the unit. This rating should be a key purchasing factor for any consumer and it should carry even more weight for individuals that live in a warmer climate. In warmer climates, the cooling season will be longer, which means a higher SEER rated air conditioner can save a significant amount of money per year.


The most notable difference between the SEER rating and the EER rating is that SEER is the more commonly used efficiency metric for air conditioners on the modern market. The EER rating used to be the standard, but the SEER was later introduced and has since taken its place as the standard.

The technical difference between the SEER and the EER is in how they are tested. The EER tests for operational efficiency under specific conditions and is a more direct method of calculation, whereas the SEER is a test to determine the operational efficiency over the course of a whole season.

Checking the SEER rating of an air conditioner can be a convenient way to determine whether the unit will provide adequate efficiency. While it may not be the only factor when it comes to getting the right air conditioner, it should be a major factor. If an air conditioner that costs slightly more has a SEER rating that is better by a couple of points, the user can expect to recover the additional costs through lower energy bills. Every air conditioner comes with a SEER rating and the number can usually be found on the unit’s energy efficiency label.