SEER ratings refer to the Seasonal Energy Efficiency Ratio of an AC unit. It is a measure of an air conditioner’s cooling efficiency over an entire cooling season, taking into account both the energy consumed and the cooling output provided. The higher the SEER rating, the more electrically efficient the air conditioner is, which means it can provide the same level of cooling while using less energy.

SEER ratings are determined by dividing the total cooling output of the system in British thermal units (BTUs) by the total energy consumption in watt-hours. The U.S. Department of Energy sets minimum SEER requirements for air conditioners to promote energy efficiency and reduce environmental impact.