Grant rules checked against Ofgem on 15 October 2026
Do you need planning permission for an air source heat pump?
Published and last updated 15 October 2026
Most air source heat pumps in England don't need planning permission because they count as permitted development. Since 29 May 2025 the rule banning units within one metre of a boundary has gone, homes can have up to two units, and the size limit has risen to 1.5 cubic metres.
What changed in May 2025?
Three changes took effect on 29 May 2025: the one-metre boundary rule was scrapped, the limit rose from one to two heat pumps per home, and the maximum size rose from 0.6 to 1.5 cubic metres.
Air-to-air units now have the same rights as air-to-water.
What conditions still apply?
The installation must still meet noise limits, set out in the MCS 020 standard, and your installer checks this as part of the design.
Siting and appearance conditions still apply.
When do you still need planning permission?
You may need permission or consent for a listed building, and should check first in a conservation area or if your home's permitted development rights have been removed.
Check with your local planning authority.
What about flats and leasehold homes?
Flats often need permission from the freeholder and may fall outside householder permitted development, so check before getting quotes.
Are the rules the same in Wales?
No. Wales has its own permitted development rules, so check with your local planning authority before installing.
How loud is an air source heat pump?
Modern outdoor units produce a low hum while running, and siting them away from bedroom windows and neighbours' windows keeps noise down.
Frequently asked questions
Do I need to tell my neighbours?
It's not required under permitted development, but it's a courtesy.
Can the unit go on the front wall?
Possibly; your installer checks the siting conditions.
Do I need building regulations approval?
Your MCS installer handles the required notifications as part of the installation.