SEER, or The Seasonal Energy Efficiency Ratio, is a rating system that breaks down how efficient a system is into its parts. The Energy Guide develops due to a mandate from the United States Department of Energy that required minimum efficiency ratings to be met by air conditioners. A minimum SEER rating of 10 requires for all central air conditioners upon passing legislation that began in 1987 and took effect in 1992.
Seasonal Energy Efficiency Ratio, also known as SEER, is the ratio of the electrical wattage input into the system to the amount of British Thermal Units (BTU) output by the air conditioner. The higher the system's SEER rating, the more efficient it is, which means it will have lower operating costs during warmer months.