SEER stands for Seasonal Energy Efficiency Ratio. The SEER measures air conditioning and heat pump cooling efficiency, which is calculated by the cooling output for a typical cooling season divided by the total electric energy input during the same time frame. A SEER rating is a maximum efficiency rating, similar to the miles per gallon for your car. Your car might get 28 miles per gallon on the highway, but if you’re stuck in city traffic it could be lower. If your air conditioner is 21 SEER, that’s its maximum efficiency.
A higher SEER rating means greater energy efficiency. The minimum standard SEER is 13 for air conditioners. Most modern air conditioners have a SEER that ranges from 13 to 21. Trane air conditioners range from 14.5 SEER up to 22 SEER. It’s important to remember the efficiency of your system can also depend on the size of your home your current ductwork and other variables.