The SEER (Seasonal Energy Efficiency Ratio) rating measures the cooling output of an air conditioner over a typical cooling season, divided by the energy it consumes in Watt-Hours. It is a metric used to gauge the efficiency of air conditioning units. The higher the SEER rating, the more efficient the air conditioner is. As of 2024, the U.S. Department of Energy requires a minimum SEER rating of 14 for new air conditioners in most of the United States, with some regions requiring a minimum of 15 due to their hotter climates. A good SEER rating for an air conditioner would be one that is higher than these minimum standards. Generally, a SEER rating of 15 or above is considered efficient and can lead to significant savings on energy bills in the long run. Units with SEER ratings of 20 or above are considered highly efficient, although they come with a higher initial cost. When selecting an air conditioner, balancing the SEER rating with the upfront cost and your long-term energy savings is crucial to making a cost-effective decision.