A heat pump takes heat at a low temperature from the air or ground and increases it to a higher temperature, before transferring it into homes for central heating and hot water. This heat extraction method means that the efficiency of heat pumps declines in colder temperatures.

However, experiments from researchers at Oxford University and the Regulatory Assistance Project think tank have shown that, even at temperatures as low as -30°C, heat pumps still outperform fossil-fuel-powered systems.

Heat pumps have emerged as a key tool in the global transition towards clean and reliable energy as they can be powered by renewables such as solar and wind, which are carbon neutral. However, concerns have been raised that their declining efficiency in cold weather presents a barrier to their adoption.

The researchers found that even well below 0°C, heat pump efficiency is still significantly higher than fossil fuel and electric resistive heating systems at an...