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Energy efficiency ratio, a measure to asses heat pumps;
Seasonal energy efficiency ratio
The efficiency of air conditioners are 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 a simulated, typical cooling-season divided by the total electric
energy input in watt-hours (W·h) during the same period.
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 (e.g., 8 hours per day
for 125 days) would provide an annual total cooling output of:
5000 Btu/h × 1000 h = 5,000,000 Btu
With a SEER of 10, the an annual electrical energy usage would be about:
5,000,000 Btu ÷ 10 = 500,000 W·h
This is equivalent to an average power usage during the cooling season of:
500,000 W·h ÷ 1000 h = 500 W
The average power usage may also be calculated more simply by:
Average power = (Btu/h) ÷ (SEER, Btu/W·h) = 5000 ÷ 10 = 500 W
