Do You Need Planning Permission for An Air Source Heat Pump?

Since 1 December 2011, the installation of air source heat pumps on residential premises has been considered "permitted development"—meaning no planning permission is required—provided that all the following limits and conditions are met.

These permitted development rights apply to the installation, alteration, or replacement of air source heat pumps on houses or blocks of flats, or within their curtilage (gardens or grounds), including on outbuildings within that curtilage. Blocks of flats must consist entirely of flats (e.g., they must not contain commercial premises).

Limits and conditions to be met:

1. Development is permitted only if the air source heat pump installation complies with the Microgeneration Certification Scheme (MCS) planning standards (MCS 020) or equivalent standards. Learn more about the scheme. From 28 May 2026, MCS 020 will be the only permitted certification scheme.

2. The volume of the outdoor compressor unit (including its housing) must not exceed 1.5 cubic metres for houses or 0.6 cubic metres for blocks of flats.

3. Only the first installation of an air source heat pump qualifies as permitted development for non-detached houses or blocks of flats. For detached houses, the first two installations qualify as permitted development.

4. Development is permitted only if there are no existing wind turbines on the building or within its curtilage. Adding a wind turbine or an air source heat pump to the same plot requires planning permission.

5. Installing an air source heat pump on a pitched roof is not permitted development. If installed on a flat roof, all components of the air source heat pump must be at least one metre away from the outer edge of the roof.

6. Permitted development rights do not apply to installations within the curtilage of a listed building or on a site designated as a scheduled monument.

7. In a conservation area or World Heritage Site, air source heat pumps must not be installed on a wall or roof facing a highway, nor be positioned closer to any highway adjacent to the plot than any other part of the building. 8. On land outside a conservation area or World Heritage Site, if the wall faces a road, the air source heat pump must not be installed on any part of the wall above ground level.

* Please note: Planning conditions, Article 4 Directions, or other restrictions may remove "permitted development" rights.

In addition, the following conditions must be met. The air source heat pump must:

1. Not be used solely for cooling purposes.

2. Be removed as soon as reasonably practicable when no longer needed for microgeneration.

3. Be sited to minimize the impact on the building's appearance and the surrounding environment.

You may wish to discuss with your local planning department whether all these restrictions and conditions can be met.