What is SEER in an air conditioning unit?

SEER is an acronym that stands for Seasonal Energy Efficiency Ratio. It is essentially a rating that reflects the efficiency of an air conditioning unit. A SEER rating is the cooling output in BTUs divided by the total electric energy input in Watts over the same period. The higher the SEER number, the more energy efficient the unit. Higher rated SEER A/Cs and heat pumps can pay for themselves since they often consume less electricity per BTU used.