An air source heat pump extract heat from the air outside your building – even at temperatures as low as minus 15 degrees celsius. It then uses it to warm up water for radiators or under floor heating systems or to warm the air indoors. The pump used to extract the heat needs to be powered by electricity, so to make it a genuinely renewable technology you should generate as much of your own electricity as possible using a renewable energy source, such as solar PV.


There are 2 main types of air source heat pump systems: 

  1. air-to-water system: this uses the heat to warm up water – though not as hot as a standard boiler system would, so it’s better suited to under floor heating than conventional radiators.
  2. air-to-air system: this produces warm air, which is circulated around your building by fans. Typically one unit would be used for one room. These units can often also be used in summer for cooling.


Is my building suitable? You will need a space outside your building where a unit can be fitted to a wall or place on the ground. A sunny wall is ideal. Air source heat pumps produce less heat than regular boilers so it is essential that your building is highly insulated and draft proof for the system to work effectively. Air source heat pumps work most efficiently on new build or highly refurbished buildings, as these are built to current insulation standards.


How much do air source heat pumps cost? As a guide, a system for a domestic property may cost between £7,000 and £15,000.