Ground source heat pumps work in a very similar way to air source heat pumps but instead, they absorb energy from the ground, which has been heated by the sun’s rays. They’re more efficient than their air-source sisters, because in winter when we need more heat, the ground is much warmer than the air.

However, they are more expensive to install. For every kW of electricity used by your ground source heat pump, you could get up to 4kW of heat back, so it’s definitely worth the investment.