Most air source heat pumps on houses in England do not need planning permission, because they count as permitted development as long as they meet set conditions, including the MCS planning standards and noise assessment. Since 29 May 2025 those conditions have been relaxed: up to two units are allowed on a house, each outdoor unit can be up to 1.5 m³, and the old rule about siting within 1 m of a boundary has gone.
Wales, Scotland and Northern Ireland each have their own permitted development rules for heat pumps, and listed buildings, flats and some conservation-area positions need more care everywhere. This guide explains the rules in England, when permission is needed, and how the installer checks what applies at your home.
What is permitted development for heat pumps?
Permitted development rights let you carry out certain types of work without applying for planning permission, provided the work meets set conditions and limits.
In England, air source heat pumps on houses have been permitted development for some years, and the rules were updated on 29 May 2025. Each nation of the UK sets its own permitted development rules, so the details in the next two sections apply to England only.
Permitted development is a set of conditions rather than a blanket exemption. If an installation does not meet every condition, such as the number or size of outdoor units, the position or the noise limit, it needs a planning application instead. That is why the details of your home and the chosen position are checked at survey rather than assumed.
What changed for heat pump permitted development in England?
Since 29 May 2025, permitted development in England allows larger and more flexibly sited air source heat pumps on houses.
| Rule (England) | Since 29 May 2025 |
|---|---|
| Number of air source heat pumps on a house | Up to two |
| Size of each outdoor unit | Up to 1.5 m³ |
| Distance from the boundary | The old rule requiring planning permission within 1 m of a boundary has been removed |
| Noise and siting | The installation must still meet the MCS planning standards, including the noise assessment |
Removing the 1 m rule matters most for terraced and semi-detached homes, where the only sensible spot for a unit is often close to a side or rear boundary. A unit can now go there under permitted development, as long as the other conditions are met.
The larger size allowance makes room for bigger outdoor units, which some larger or older homes need to meet their heat loss.
What are the MCS planning standards and noise assessment?
The MCS planning standards are the technical conditions a heat pump installation must meet to count as permitted development in England, and the noise assessment is the central part of them.
The noise assessment estimates the sound level from the outdoor unit at the nearest window of a neighbouring home, using the unit's published sound power level, the distance, and any barriers or reflecting walls nearby. If the result is within the limit, the position qualifies. If not, the installer looks at another position, a different unit or a barrier, or the installation needs a planning application.
Heat pumps are designed to run quietly, but the noise check is why the position of the outdoor unit matters. A spot with good airflow, away from neighbours' bedroom windows and not boxed into a corner, usually works well for neighbours and for efficiency. See our guide to heat pump noise and siting.
When does a heat pump need planning permission?
A heat pump needs planning permission or other consent when the home or the position falls outside permitted development, most often for listed buildings, flats, and some front-facing or conservation-area positions.
- Listed buildings: fitting an outdoor unit or making related changes needs listed building consent
- Flats and apartments: permitted development for houses does not automatically cover flats, so permission may be needed
- Conservation areas: some positions, particularly those visible from a road, may need permission
- Front elevations: a unit on a wall facing the road may need permission
- Noise: a position that does not pass the MCS noise assessment needs a planning application
- Beyond the limits: in England, more than two units, or a unit larger than 1.5 m³, falls outside permitted development
If you own a flat, you may also need consent from the freeholder or management company under your lease. That is separate from planning, so it is worth checking your lease early.
What are the heat pump planning rules in Wales, Scotland and Northern Ireland?
Wales, Scotland and Northern Ireland each have their own permitted development rules for heat pumps, and the limits and conditions differ from England's.
We check what applies in your nation at the survey. If the position needs permission, we tell you before you accept a quote, and the timing of any application is built into the plan.
If you are reading advice online, check which nation it refers to. Much of what is published about heat pump planning describes the rules in England, and a limit that applies there may not apply in Wales, Scotland or Northern Ireland.
Listed building controls apply across the UK, and every nation has conservation areas, so the same care applies to historic homes wherever you live.
How does the installer check planning for my heat pump?
The installer checks planning as part of the home survey, before a position for the outdoor unit is agreed and before you accept a quote.
- Confirming which nation's rules apply and whether the home is a house or a flat
- Checking whether the building is listed or in a conservation area
- Measuring the proposed position, the distance to neighbouring windows and any barriers
- Running the MCS noise assessment for the chosen unit and position
- Checking that the size and number of outdoor units are within the limits
- Agreeing a drainage route for defrost water and access for servicing
If everything is within permitted development, the noise assessment and siting are recorded with the installation. If permission or consent is needed, you decide whether to apply or choose another position, and nothing is ordered until you accept the written quote.
Questions
Do I need planning permission for an air source heat pump in England?
Usually not, for a house. Since 29 May 2025, permitted development in England allows up to two air source heat pumps on a house, each outdoor unit up to 1.5 m³, with the old 1 m boundary rule removed. The installation must meet the MCS planning standards, including the noise assessment. Listed buildings, flats and some conservation-area positions may need permission.
Can my heat pump go close to my neighbour's fence?
In England, yes, as long as the other permitted development conditions are met. The old rule requiring planning permission within 1 m of a boundary was removed from 29 May 2025. The position must still pass the MCS noise assessment and needs good airflow and space for servicing. Wales, Scotland and Northern Ireland have their own rules, which we check at survey.
I live in a listed building. Can I have a heat pump?
Often, yes, but you need listed building consent before fitting the outdoor unit or making related changes, wherever you live in the UK. A discreet position, such as a rear garden away from historic features, and early contact with the council's conservation officer both help. We check what applies at the survey, before you commit to anything.
Who checks whether my heat pump needs planning permission?
We check planning as part of the free survey for installation enquiries, including your nation's rules, listed status, conservation areas and the MCS noise assessment. If permission or consent is needed, we tell you before you accept a quote, and any application is made in your name as the owner. Nothing is ordered until you accept the written quote.
Sources
- Heat pumps – Planning Portal
- MCS (Microgeneration Certification Scheme)
- Air source heat pumps – Energy Saving Trust
Scheme figures and price cap rates checked October 2026.