COP Rating

The COP rating (Coefficient of Performance) is a measure of a heat pump's energy efficiency, expressed as the ratio of heat output to electrical input. For example, a heat pump with a COP of 3.5 produces 3.5 kilowatt-hours of heat for every 1 kilowatt-hour of electricity consumed. The higher the COP, the more efficient the heat pump and the lower its operating costs.

COP is not a fixed value — it varies with operating conditions, particularly the temperature difference between the heat source and the heat output. An air-source heat pump has a higher COP in mild weather and a lower COP during extreme cold, because extracting heat from very cold air requires more energy. At minus 20 degrees Celsius, a typical air-source heat pump may have a COP of only 1.5 to 2.0.

To account for this variation, the industry uses SCOP (Seasonal COP), which represents the average COP over an entire heating season weighted by the local climate. SCOP provides a more realistic picture of real-world efficiency than a single COP measurement at ideal conditions. When comparing heat pumps, always compare SCOP values for your climate zone.

A declining COP — manifested as higher electricity bills for the same heating demand — can indicate maintenance issues such as dirty filters, low refrigerant charge, a frosted outdoor coil, or fan problems. Regular professional maintenance helps maintain the heat pump's rated COP throughout its service life and ensures optimal energy efficiency.