A fridge but in reverse? The fascinating science of heat pumps – visualised

Despite being more like a refrigerator than a gas boiler, this home heating technology could slash Britain's emissions, and bills

Only 1% of British homes have a heat pump, but to hit the government's climate goals, an estimated 80% of homes should be heated by one in the next 25 years.

Whereas gas boilers burn gas to produce heat, heat pumps do something more complicated. Sometimes described as working like a fridge in reverse", they use a mixture of evaporation and condensation to transfer heat from outside to inside a building. In a cold winter, it can be hard to understand how these devices work.