Do I need planning permission for an air source heat pump?
Usually not. Since May 2025 the outdoor unit can be up to 1.5 m³, a detached house can have 2, and there's no minimum gap to the boundary: what matters is the MCS noise standard. Check yours against every rule, including ground and water source heat pumps.
What changed on 29 May 2025
Much of the advice online predates these changes, made by The Town and Country Planning (General Permitted Development) (England) (Amendment) Order 2025 (SI 2025/560).
- The rule keeping an air source heat pump away from the boundary was removed. Before: “any part of the air source heat pump would be installed within 1 metre of the boundary of the curtilage of the dwellinghouse or block of flats;” Now: removed.
- A detached house can now have two air source heat pumps (it was one per building). Before: “the development would result in the presence of more than 1 air source heat pump on the same building or within the curtilage of the building or block of flats;” Now: “more than two air source heat pumps on, or within the curtilage of, a detached dwellinghouse;”
- The outdoor unit can now be larger on a house. Before: “the volume of the air source heat pump's outdoor compressor unit (including any housing) would exceed 0.6 cubic metres;” Now: “in the case of the installation of an air source heat pump on, or within the curtilage of, a dwellinghouse, exceed 1.5 cubic metres;”
- Only the MCS Planning Standards count now: "equivalent standards" were removed. A transition let installations that met all the old limits rely on them until the end of 28 May 2026; that has now ended. Before: “Development is not permitted by Class G unless the air source heat pump complies with the MCS Planning Standards or equivalent standards.” Now: “Development is not permitted by Class G unless the air source heat pump complies with the MCS Planning Standards”
- It no longer has to be used only for heating: it just mustn't be used only for cooling. Before: “the air source heat pump is used solely for heating purposes;” Now: “the air source heat pump is not solely used for the purpose of cooling;”
Watch: Warm Homes Plan: heat pump consultation. The government's Warm Homes Plan says MHCLG and DESNZ "will consult on further permitted development rights for air source heat pumps" in 2026. No consultation had been published when we checked on 14 October 2026. Until a new Order is made, the current rules apply. Source
1. Is the house in a conservation area? (optional)
Conservation areas and World Heritage Sites have stricter siting rules. We check what's published for your postcode.Your postcode stays in your browser. We only fetch the data for its first half (for example "SW1A"). See the map and everything published for this postcode
2. Your heat pump
This is an example: change the figures to yours.
Likely permitted development, with things to check
Everything we can measure fits. Read the 3 points marked Check below before you build.
This is guidance, not legal advice. For certainty, apply to your council for a Lawful Development Certificate.
The rules, one by one
- FitsMeets the MCS Planning Standards (noise)You said your MCS-certified installer has confirmed it meets the MCS 020(a) noise standard.Source:
Schedule 2, Part 14, Class G, paragraph G.1
“Development is not permitted by Class G unless the air source heat pump complies with the MCS Planning Standards”
- FitsHow many: no more than 1 (shares a party wall)Yours: 1 in total. Limit: 1 for a house that shares a party wall with a neighbouring building.Source:
Schedule 2, Part 14, Class G, paragraph G.2(a)(i)(aa)
in the case of the installation of an air source heat pump, the development would result in the presence of — “more than one air source heat pump on, or within the curtilage of— aa a dwellinghouse which is not a detached dwellinghouse;”
- FitsOutdoor unit: max 1.5 m³ including any housing1.1 m × 0.85 m × 0.45 m = 0.42 m³. Yours: 0.421 m³. Limit: 1.5 m³.Source:
Schedule 2, Part 14, Class G, paragraph G.2(d)(i)
the volume of the air source heat pump's outdoor compressor unit (including any housing) would — “in the case of the installation of an air source heat pump on, or within the curtilage of, a dwellinghouse, exceed 1.5 cubic metres;”
- FitsConservation area or World Heritage Site: not on a wall or roof facing a roadIt won't be on a wall or roof that fronts a highway.Source:
Schedule 2, Part 14, Class G, paragraph G.2(j)(i)
in the case of land within a conservation area or which is a World Heritage Site the air source heat pump— “would be installed on a wall or a roof which fronts a highway; or”
- FitsConservation area or World Heritage Site: not nearer a road than the houseIt won't be nearer to a highway bordering the garden than the house is.Source:
Schedule 2, Part 14, Class G, paragraph G.2(j)(ii)
in the case of land within a conservation area or which is a World Heritage Site the air source heat pump— “would be installed so that it is nearer to any highway which bounds the curtilage than the part of the dwellinghouse or block of flats which is nearest to that highway; or”
- FitsNot above the ground floor on a wall facing a roadIt won't be on a wall of the house.Source:
Schedule 2, Part 14, Class G, paragraph G.2(k)
in the case of land, other than land within a conservation area or which is a World Heritage Site, the air source heat pump would be installed on a wall of a dwellinghouse or block of flats if— “that wall fronts a highway; and (ii) the air source heat pump would be installed on any part of that wall which is above the level of the ground floor storey.”
- FitsNot used only for coolingIt will be used for heating (it may cool too).Source:
Schedule 2, Part 14, Class G, paragraph G.3(aa)
“the air source heat pump is not solely used for the purpose of cooling;”
- FitsNo wind turbine on the house or in the gardenNo wind turbine.Source:,
Schedule 2, Part 14, Class G, paragraph G.2(b)
“in the case of the installation of an air source heat pump, a wind turbine is installed on the same building or within the curtilage of the dwellinghouse or block of flats;”
Schedule 2, Part 14, Class G, paragraph G.2(c)
“in the case of the installation of an air source heat pump, a stand-alone wind turbine is installed within the curtilage of the dwellinghouse or block of flats;”
- FitsThe house isn't a listed buildingYou said it isn't.Source:
Schedule 2, Part 14, Class G, paragraph G.2(i)
“the air source heat pump would be installed on a building or on land within the curtilage of the dwellinghouse or the block of flats if the dwellinghouse or the block of flats is a listed building;”
- FitsNot on a scheduled monumentNot on a scheduled monument.Source:
Schedule 2, Part 14, Class G, paragraph G.2(h)
“the air source heat pump would be installed on a site designated as a scheduled monument;”
- NoteSited to minimise its effectPlace it, so far as practicable, where it least affects how the building looks and the area's amenity, for example out of view and away from neighbours' windows.Source:,
Schedule 2, Part 14, Class G, paragraph G.3(b)
“the air source heat pump is, so far as practicable, sited so as to minimise its effect on the external appearance of the building;”
Schedule 2, Part 14, Class G, paragraph G.3(c)
“the air source heat pump is, so far as practicable, sited so as to minimise its effect on the amenity of the area; and”
- NoteRemoved when no longer neededIt must be taken away as soon as reasonably practicable once it's no longer needed.Source:
Schedule 2, Part 14, Class G, paragraph G.3(d)
“the air source heat pump is removed as soon as reasonably practicable when no longer needed.”
- CheckConservation area or World Heritage SiteWe can't confirm whether you're in a conservation area or World Heritage Site, where the siting rules are stricter. Enter your postcode, or answer the question.Source:
Schedule 2, Part 14, Class G, paragraph G.2(j)(i)
in the case of land within a conservation area or which is a World Heritage Site the air source heat pump— “would be installed on a wall or a roof which fronts a highway; or”
- CheckNo Article 4 direction removes these rightsEnter your postcode above and we'll check what your council has published.Source:
Article 4(1)
“may make a direction under this paragraph that the permission granted by article 3 does not apply to— (a) all or any development of the Part, Class or paragraph in question in an area specified in the direction; or (b) any particular development, falling within that Part, Class or paragraph, which is specified in the direction”
- CheckNo planning condition removes these rightsWas your house built in the last 30 years, or on an estate? A planning condition may have removed these rights. Check the council's planning register.Source:
Article 3(4)
“Nothing in this Order permits development contrary to any condition imposed by any planning permission granted or deemed to be granted under Part 3 or Part 13 of the Act otherwise than by this Order”
3. Do your house's planning conditions allow it?
Was your house built in the last 30 years, or on an estate? Planning conditions may have removed these rights. When a council grants planning permission for new houses, it can attach a condition that removes some or all permitted development rights, for example extensions, outbuildings or fences. This is common on newer estates. If there is such a condition, the rights in this checker do not apply and you need planning permission. Open data does not record these conditions, so this tool cannot check them for you. The 30 years is a prompt, not a legal cut-off. A condition on a permission of any age still applies.
How to check
- Find your council's online planning register (search for the council name and "planning applications search").
- Search by your address, your road name or the estate name for the permission that allowed the house to be built. On an estate this is usually the developer's application, which may list many plots.
- Open the decision notice and read the conditions. Look for any condition that mentions the General Permitted Development Order, "permitted development", or Part 14 (renewable energy) of Schedule 2, or that says no heat pumps or other equipment may be put up without permission. A condition that only removes other rights (for example extensions or fences) doesn't affect this project.
- Also check any later permission for your house, such as an earlier extension. Its conditions can remove rights too.
- If the permission is old and not online, ask the council's planning department, or look at the local authority search in your purchase documents.
- If you are still unsure, ask the council or apply for a Lawful Development Certificate.
Heat pumps and planning: answers
Do I need planning permission for an air source heat pump?
Usually not. An air source heat pump is permitted development if its outdoor unit is no bigger than 1.5 m³, it meets the MCS noise standard, it isn't on a pitched roof, and your house has no more than 1 (or 2 if it's detached).
Stricter siting rules apply in conservation areas and World Heritage Sites, and the rights don't apply to a listed house.
Is there still a 1 metre rule for heat pumps?
No. Since 29 May 2025 there is no minimum distance from the boundary. The old rule that a heat pump couldn't be within a metre of the boundary was removed. Instead, it must meet the MCS noise standard at your neighbours' windows.
Can I have two heat pumps without planning permission?
Yes, on a detached house (one that doesn't share a party wall with a neighbouring building): up to 2. Semi-detached and terraced houses can have 1.
Can a heat pump go at the front of the house?
Outside conservation areas and World Heritage Sites, yes on the ground, and on a wall facing a road at ground-floor level only. In a conservation area or World Heritage Site it can't go on a wall or roof that fronts a highway, or nearer a road than the house.
What are the MCS Planning Standards?
A noise calculation (MCS 020(a)) that works out the unit's sound level at the nearest neighbouring window. An MCS-certified installer does it. "Equivalent standards" stopped counting on 29 May 2025; a transition for installations that met all the old limits ended on 28 May 2026.
Do ground source heat pumps need planning permission?
Usually not: the Order permits a ground source or water source heat pump within the grounds of a house and sets no size or siting limits for it. Article 4 directions, planning conditions and listed building consent can still apply.
Sources
- The Town and Country Planning (General Permitted Development) (England) Order 2015, Schedule 2, Part 14, Classes C, D and G (heat pumps on domestic premises), on legislation.gov.uk. Text in force from 27 August 2026, checked 14 October 2026, including the changes made by SI 2025/560.
- MCS 020(a), the Microgeneration Certification Scheme's air source heat pump sound calculation, which the Order calls the "MCS Planning Standards".
More from Planning Toolkit
- Check my addressWhether you're in a conservation area, World Heritage Site or Article 4 area.
- Fence, wall and gate height checkerHow high a fence, wall or gate can be: next to a road or not, on a slope, with trellis on top.
- Garden room and outbuilding checkerHeight near the boundary, roof shape, eaves, how much of the garden it covers, and use.
- Rear and side extension checkerSingle and two-storey, the larger home extension route, eaves near a boundary.
- Loft and dormer checkerThe volume allowance, front roof slopes, side windows and set-backs.