Coefficient of performance. Electric resistance heat has a COP of 1, while a heat pump with a COP of 3 delivers three units of heat for each unit of electricity, by moving heat rather than making it. COP falls as the temperature gap between source and sink grows, so heat pump COP drops on cold days. Multiply COP by 3.412 to get EER.
At 47 outside this heat pump runs a COP of 3.6, at 5 degrees it's down near 1.9, still beats the strips.
Also heard as
- coefficient of performance
Related terms
EER
Energy efficiency ratio: cooling output in Btu per hour divided by watts of input at one hot, full-load test point.
HSPF
Heating seasonal performance factor: a heat pump's seasonal heating output in Btu divided by its electricity use in watt-hours.
Heat pump
A refrigeration system that can reverse its flow to move heat indoors in winter as well as outdoors in summer.
IPLV
Integrated part load value: a single weighted chiller efficiency figure that reflects operation at 100, 75, 50 and 25 percent load.