Air Source Heat Pumps in the UK - Complete 2026 Guide

How do air source heat pumps work?

An air source heat pump extracts heat from outside air - even when temperatures are as low as -20°C - and uses it to heat your home and hot water. It works like a refrigerator in reverse: a refrigerant absorbs heat from the air, is compressed (which raises its temperature), and then transfers that heat to your heating system.

For every 1 unit of electricity the pump uses, it typically produces 3-4.5 units of heat. This ratio is measured as the Seasonal Coefficient of Performance (SCOP). A SCOP of 3.5 means 3.5 kWh of heat for every 1 kWh of electricity consumed.

Is my home suitable?

Most UK homes can accommodate an air source heat pump. The key requirements are:

• Outdoor space for the unit (typically 0.5m x 0.5m x 1m - similar to a large fridge)
• A hot water cylinder (most homes with combi boilers will need one adding)
• Some level of insulation (loft and cavity wall recommended, but not essential)
• Radiators sized appropriately (often need upgrading in older properties)

How much does air source installation cost?

Total installed cost before grant: £10,000-18,000. After the £7,500 BUS grant: £2,500-10,500. Typical all-in cost for a 3-bed semi: £11,000-14,000 before grant (£3,500-6,500 after).

The wide price range reflects differences in unit size, installation complexity, whether a hot water cylinder is needed, and local installer rates.

Running costs vs gas boiler

With current Ofgem Q1 2026 tariffs (electricity 24.5p/kWh, gas 6.4p/kWh), running costs are broadly comparable for gas-heated homes. Oil and LPG users typically save £400-900/year with a heat pump.

As the electricity grid decarbonises (target: 60% renewable by 2030), heat pump running costs and emissions will improve further.