The Seasonal Energy Efficiency Ratio (SEER) is a measure of the efficiency of air conditioners and heat pumps. It is calculated by dividing the cooling output of the system over a typical cooling season by the total energy input during the same period. SEER is a measure of the cooling efficiency of the system and is usually expressed as a number ranging from 8 to 23. The higher the SEER rating, the more efficient the system is. In order to meet current energy efficiency standards, air conditioners and heat pumps must have a SEER rating of at least 13. This means that the system must be able to produce more cooling output than the energy it consumes. By investing in a system with a higher SEER rating, you can save money on your energy bills while helping to reduce your carbon footprint.