Heat pumps: The ‘geeks’ obsessing over their new heating systems

A well-installed heat pump might get three kilowatt hours (kWh) of heat for each kWh of electricity it consumes. This ratio is called the coefficient of performance, or COP – the higher it is, the better. Heat pump-watchers tend to use this figure as a means of judging how well their device is working, sometimes in friendly competition with other heat pump owners.