Most heat pumps will operate down to around -20c. This may seem odd, however, there is still sufficient energy in the air at these temperatures to be extracted; according to science, there is still energy all around us down to absolutely zero (−273.15 °C).

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Of course, the available energy in the air drops as the external temperature drops, so the amount of energy a heat pump can provide will also drop. As such, all our calculations are made at an appropriate design temperature (e.g., -1.8c in the south of England), as ultimately, it is at these temperatures that we need to ensure your heat pump has sufficient output to keep you warm.