What Changed
From 29 May 2025, homeowners in England can install air-source heat pumps under permitted development rights, removing the previous requirement for planning permission in many cases.
Key changes:
- One-metre boundary rule removed: heat pumps no longer need to be at least 1 metre from property boundaries
- Larger units allowed: increased size limits for external units
- Fewer restrictions: simplified rules for siting and noise compliance
This removes a bureaucratic bottleneck that affected an estimated 30-40% of households (based on typical property boundary constraints), making heat pump installation faster and cheaper for many homeowners.
Impact on Homeowners
Simpler planning rules mean more homeowners can proceed without planning permission delays. However, technical survey evidence requirements remain the same: installers still need clear documentation of siting, clearances, and noise constraints for system design and compliance.
Key survey requirements (unchanged):
- External unit siting: location, clearances, access routes
- Noise constraints: distance from neighbours, existing noise sources
- Air flow clearances: obstructions, ventilation requirements
- Property boundaries: measured distances (even if planning isn't needed)
These details are still documented because they affect system performance, MCS compliance, and installer liability, regardless of planning requirements.
Technical Survey Requirements
Planning permission rules changed, but technical survey evidence requirements haven't. Installers still need clear documentation of:
- Siting and clearances: where the unit goes, how much space is available
- Noise and airflow: constraints that affect system design
- Access routes: how installers will get equipment on site
Surveyors typically photograph external unit locations, measure clearances, and document constraints to support system design and MCS compliance.
What's Still Required
Even with permitted development, some properties still need planning permission:
- Listed buildings: planning consent usually required
- Conservation areas: may require planning depending on location
- Flats/apartments: building regulations and leaseholder consent still needed
- Very large units: if exceeding size limits, planning may still be required
If in doubt, homeowners should check with their local authority. Survey evidence helps support planning applications when needed.
What This Means for the Industry
The planning changes reduce administrative delays for homeowners, but technical survey evidence quality remains critical for system design and MCS compliance. Clear documentation of siting, clearances, and constraints supports smooth installations and prevents callbacks.
The changes are expected to increase the number of heat pump installations proceeding under permitted development rights, reducing the planning application burden on local authorities and speeding up installations for homeowners.