What is Cop? and is Air Conditioning an effective heater?

What is COP? COP, or Coefficient of Performance, is the ratio of cooling (or heating) to energy consumption. For example, a refrigerator with a COP of 2 moves 2 watts of heat for every watt of electricity consumed. An air conditioner with a COP of 4 moves 4 watts of heat for every watt consumed. For domestic heating, COP is also used. An electric heater has a COP of 1: each watt of power consumed produces 1 watt of heat. Conventional heat pumps have COPs of 2-5, delivering 2 to 5 times more energy than they consume. Our Air Conditioning systems heat as well and cool and are increasingly becoming more popular as a form of heating for Domestic homes as well as commercial sites, especially for those who live in an area not supplied by gas.