Air Source Heat Pump – Supporting Information

The information below provides further detail on the efficiency and environmental performance figures referenced on our Air Source Heat Pump page. These figures are based on manufacturer technical information and recognised industry and UK Government data.

Air Source Heat Pump Efficiency – Around 300%

Air source heat pumps work by transferring heat from the outside air into your home. This allows them to provide more heat energy than the electrical energy they use.

Their performance is measured using figures known as Coefficient of Performance (COP) and Seasonal Coefficient of Performance (SCOP). For example, a seasonal performance figure of 3 means that, on average, approximately 3 units of heat are provided for every 1 unit of electricity used.

This is the basis of our statement that air source heat pumps can operate at an efficiency in the region of 300%.

The Vaillant aroTHERM plus range installed by Union Technical has published seasonal performance figures of up to 5.03, depending on the model and operating conditions.

Modern Gas Boiler Efficiency – Around 94%

Unlike a heat pump, a gas boiler produces heat by burning fuel. This means its efficiency is measured differently.

Modern A-rated condensing gas boilers typically have a seasonal space-heating efficiency of around 92–94%, depending on the manufacturer and model.

We therefore use “around 94%” when comparing the efficiency of a modern gas boiler with an air source heat pump.

Examples of this level of performance can be found within published technical information for modern Ideal Logic+ Combi² and Vaillant ecoTEC/ecoFIT boilers.

Environmental Impact

Air source heat pumps use electricity rather than directly burning fossil fuels within the home.

Although electricity generation still has an associated carbon impact, a heat pump can provide approximately 3 units of heat for every 1 unit of electricity used at a SCOP of 3. This means significantly less energy is required to provide the same amount of useful heat.

Using UK Government greenhouse gas conversion factors alongside an illustrative heat pump performance of SCOP 3 and a modern gas boiler efficiency of 94%, our comparison indicates that the carbon emissions associated with providing the same amount of heat can be approximately 60% lower with an air source heat pump.

Actual performance and emissions will vary depending on factors including the heat pump system, property, operating temperatures, electricity supply and how the heating system is used.

Important Information

The figures above are provided as general comparisons to help explain the potential performance of air source heat pump technology. Actual system efficiency, energy use, running costs and carbon savings will vary between properties and depend on factors including the property itself, system design, external temperatures and how the heating system is operated.