Air source and ground source heat pumps gained permitted development rights in England in 2011. Most domestic installations don’t need planning permission — but the rules differ by type.
Air source heat pumps (ASHPs) on dwellinghouses and flats are permitted development under Part 14, Class G of the GPDO 2015, provided there is only one unit on the property, it is not on a wall or roof fronting a highway, and noise levels meet the MCS Planning Standards. Ground source heat pumps (GSHPs) are permitted development under Part 14, Class I. Listed buildings are excluded from both rights. In conservation areas, ASHPs are only permitted if not on a wall or roof fronting a highway. The ‘one pump per property’ rule for ASHPs is strict.
Air source heat pumps (ASHPs) are permitted development under Part 14, Class G of the GPDO 2015. The permitted development right covers the installation, alteration, or replacement of an air source heat pump on a dwellinghouse or a block of flats, or within the curtilage of a dwellinghouse or block of flats.
Class G is a MCS Permitted Development designation — the installation must be carried out by an MCS-certified installer or to equivalent standards, and must comply with the MCS Planning Standards (which set noise limits for ASHP installations).
Ground source heat pumps (GSHPs) are permitted development under Part 14, Class I of the GPDO 2015. Class I permits the installation, alteration, or replacement of a ground source heat pump within the curtilage of a dwellinghouse or block of flats — including the installation of ground loops or boreholes associated with the system.
Ground source heat pumps are generally less visible than air source units (the plant equipment is typically indoors and the ground loops are underground), so planning permission is rarely an issue. The main practical constraint is whether ground conditions are suitable for the installation, not planning.
| Condition | Detail |
|---|---|
| One unit only (ASHP) | Only one air source heat pump is permitted per dwelling — if one already exists, a second requires planning permission |
| Not on highway-facing wall/roof | An ASHP cannot be installed on a wall or roof that fronts a highway |
| MCS compliance | Must comply with MCS Planning Standards (sets noise limits — 42dB at nearest habitable room facade at 3 metres) |
| Volume limit | The volume of the unit must not exceed 0.6 cubic metres |
| Listed buildings excluded | Both Class G and Class I do not apply to listed buildings |
| No effect on chimney stack | The installation must not affect a chimney, flue, or soil and vent pipe |
The ASHP permitted development right (Class G) has specific exclusions:
Ground source heat pumps (Class I) have fewer restrictions — there is no conservation area restriction on Class I because the ground works are below ground and don’t affect the character of the area. Class I does not apply to listed buildings.
Extensions, loft conversions, outbuildings, solar panels — our complete guide covers everything you can build without planning permission.
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