Seasonal Energy Efficiency Rating (SEER)
Main article: Seasonal Energy Efficiency Rating
For residential homes, some countries set minimum requirements for energy efficiency. In the United States, the efficiency of air conditioners is often (but not always) rated by the Seasonal Energy Efficiency Ratio (SEER). The higher the SEER rating, the more energy efficient is the air conditioner. The SEER rating is the BTU of cooling output during its normal annual usage divided by the total electric energy input in watt hours (W·h) during the same period. [6]
SEER = BTU ÷ W·h
For example, a 5000 BTU/h air-conditioning unit, with a SEER of 10, operating for a total of 1000 hours during an annual cooling season (i.e., 8 hours per day for 125 days) would provide an annual total cooling output of:
5000 BTU/h × 1000 h = 5,000,000 BTU
which, for a SEER of 10, would be an annual electrical energy usage of:
5,000,000 BTU ÷ 10 = 500,000 W·h
and that is equivalent to an average power usage during the cooling season of:
500,000 W·h ÷ 1000 h = 500 W