Determining Heat Pump Swimming Pool Heater Efficiency
The energy efficiency of heat pump swimming pool heaters is measured by coefficient of performance (COP). The higher the COP number, the more efficient. However, there is no standard test for measuring the COP. Therefore, you really can't compare the COPs of different models unless you know that the manufacturers used the same test for each model. For example, the same heat pump will operate at a higher COP when the outside air temperature is higher.
Typically, manufacturers measure the COP by testing a heat pump pool heater with an outdoor temperature of 80ºF and pool temperature of 80ºF. COPs usually range from 3.0 to 7.0, which converts to an efficiency of 300%–700%. This means that for every unit of electricity it takes to runs the compressor, you get 3–7 units of heat out of the heat pump.