Do heat pumps work in cold UK winters?

Yes. Modern air-source heat pumps operate efficiently at outdoor temperatures as low as -15°C to -25°C depending on the model. The COP decreases at very low temperatures but remains above 1 (i.e., still more efficient than direct electric heating). Proper sizing and insulation are key to good performance.

Is a heat pump zero carbon?

A heat pump produces zero direct emissions (no Scope 1). However, it consumes electricity, which has associated Scope 2 emissions based on the grid carbon intensity. As the UK electricity grid decarbonises, heat pump emissions approach zero. Pairing a heat pump with renewable electricity (via a green tariff or solar PV) further reduces the carbon footprint.

Heat Pump

A heat pump is an electrically powered device that extracts heat from the air, ground, or water and transfers it into a building for heating (or reverses for cooling), producing 2–4 times more heat energy than the electrical energy it consumes.

What is Heat Pump?

Heat pumps are a key decarbonisation technology for heating, which accounts for approximately 37% of UK carbon emissions. By transferring heat rather than generating it through combustion, heat pumps are 2–4 times more efficient than gas boilers — this ratio is called the Coefficient of Performance (COP). An air-source heat pump with a COP of 3 produces 3 kWh of heat for every 1 kWh of electricity consumed.

The three main types are air-source (most common, extracting heat from outdoor air), ground-source (extracting heat from the ground via buried pipes), and water-source (extracting heat from a water body). Air-source heat pumps are the most widely deployed in the UK due to lower installation costs and simpler retrofitting.

The UK government’s Boiler Upgrade Scheme provides grants of up to £7,500 towards the cost of installing a heat pump in domestic and small commercial properties. For larger commercial and industrial applications, the Renewable Heat Incentive (now closed to new applications) was replaced by other support mechanisms. As the electricity grid decarbonises, the carbon savings from heat pumps will increase over time.

Practical Examples

A commercial office replaces its gas boiler with an air-source heat pump, reducing its Scope 1 heating emissions by 75% and its energy bills by 30%.

A hotel chain installs ground-source heat pumps at three rural properties, eliminating oil heating and reducing Scope 1 emissions by 200 tCO₂e per year.

A school installs an air-source heat pump alongside improved insulation, achieving the dual benefit of lower heating emissions and improved thermal comfort.

How Climatise Helps

Climatise models the emissions impact of switching from gas or oil heating to heat pumps, quantifying the Scope 1 reduction and any increase in Scope 2 electricity consumption to provide a clear net benefit analysis.

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