Permitted development rights – what installers need to know for air source heat pump installs
Installing an air source heat pump (ASHP) involves more than selecting the right equipment and designing an efficient system.
Understanding the implications of planning rules and how they could potentially affect the install, assessing the proposed location carefully and keeping the right evidence to demonstrate compliance are all essential aspects that should be considered.
In England and Wales, most ASHP installs are considered permitted development, particularly with rules updated for England in May 2025 and more recently in Wales in June 2026. This means, generally speaking, planning permission isn’t required, though there are some important conditions that still need to be met and specific factors that installers should still keep in mind.
Getting the planning requirements right from the start will help you avoid potentially costly changes, unnecessary delays and potential compliance issues, whilst giving customers greater confidence in their installation.
In this article, we’ll cover:
What the latest permitted development rights for ASHPs are
When planning permission might still be needed
Compliance with MCS standards
Steps you should take during installations
How we can support you with delivering compliant projects
What the latest permitted development rights for ASHPs are
The updated rules have removed or at least lessened many of the challenges that installers have had in the past. One of the main changes is there are no minimum boundary distances, which was previously one metre. This enables greater flexibility for siting the outdoor unit.
Other significant changes are being able to have up to two units installed for detached properties and the size of the heat pump increasing from 0.6 to 1.5 cubic metres for dwellings, making heat pump installations viable for a greater range of properties. ASHPs can also be used for cooling, meaning air-air heat pumps can now also benefit from PDR.
These changes need to be taken into consideration together with the existing PDR requirements of noise limits and whether the property is a listed building and/or considered to be within a conservation area.
Different arrangements remain in place across the devolved administrations. Please refer your relevant administration or local planning authority. Further information can also be viewed below:
