--- title: "Heat Pump 1m Rule Scrapped: Permitted Development Rules 2026" url: https://www.greentechrenewables.co.uk/ashp/what-is-the-1m-rule-for-heat-pumps description: "The 1m boundary rule for heat pumps ended on 29 May 2025. What England's permitted development rules now allow: 1.5m³ units, two per detached home, 37dB noise test." lang: en-GB --- # What Was the 1m Rule for Heat Pumps — and What Replaced It? Updated 28 September 2026 · England permitted development rules Until 29 May 2025, an air source heat pump in England only counted as permitted development if it sat at least 1 metre from your property boundary. That rule has gone. Today the test is noise, not distance: if the installation passes the MCS 020(a) noise assessment, it can go closer to the boundary. ### Quick answer - The 1m boundary rule no longer applies in England (removed 29 May 2025). - Outdoor units can now be up to 1.5 m³, and detached homes can have two. - The installation must meet the MCS 020(a) noise limit of 37 dB(A) at the neighbour's assessment position. View Heat Pumps: https://www.greentechrenewables.co.uk/heat-pumps 0333 577 7010: 03335777010 ## What the 1m rule was Before 29 May 2025, England's permitted development rules said an air source heat pump had to be at least 1 metre from the property boundary, the outdoor unit could be no bigger than 0.6 m³, and each home could have only one. If you couldn't meet all three, you needed planning permission. The 1m rule hit terraced houses hardest: many back yards and side passages are narrower than 2 metres, so there was simply nowhere compliant to put the unit. ## What changed on 29 May 2025 | Rule | Before 29 May 2025 | Now | | --- | --- | --- | | Distance from boundary | At least 1 m | No minimum distance | | Outdoor unit size (houses) | Up to 0.6 m³ | Up to 1.5 m³ | | Outdoor unit size (flats) | Up to 0.6 m³ | Up to 0.6 m³ (unchanged) | | Number of units | One per home | Two on detached houses, one on other homes | | Air-to-air heat pumps | Not covered | Now permitted development, including for cooling | | Noise standard | MCS 020 | MCS 020(a): 37 dB(A) at the assessment position | Source: The Town and Country Planning (General Permitted Development) (England) (Amendment) Order 2025 (https://www.legislation.gov.uk/uksi/2025/560) ## The rules that still apply Removing the 1m rule didn't remove every condition. You still need planning permission if: - The unit would go on a pitched roof. - It would go on a flat roof within 1 metre of the roof's edge. - The property is a listed building or within its curtilage. - You're in a conservation area or World Heritage Site and the unit would be on a wall or roof facing a road, or nearer the road than the house. - It's a flat in a building that also contains commercial premises. - The installation fails the MCS 020(a) noise assessment. Wales, Scotland and Northern Ireland have their own permitted development rules and still use the original MCS 020 standard, so check with your local planning authority there. ## What MCS 020(a) means for you MCS 020(a) (https://mcscertified.com/new-permitted-development-rules-in-england-air-source-heat-pump-installations-must-now-comply-with-mcs-020-a/) is the noise calculation your installer carries out. It works out the sound level from the unit at the nearest neighbour's door or window, allowing for distance, walls, fences and reflective surfaces. If the result is 37 dB(A) or lower, the installation meets the permitted development condition. It also sets the method for homes with two heat pumps. An MCS-certified installer should give you this calculation before fitting — ask for it. ## What it means for Greater Manchester homes Greater Manchester has thousands of Victorian and Edwardian terraces with small back yards, and these were the homes the 1m rule most often ruled out. They can now qualify if the noise assessment passes, which usually comes down to picking the right unit and position. Parts of Didsbury and Chorlton are conservation areas, so there the unit normally needs to go at the back or side rather than on a wall facing the street. See our air source heat pump installation in Manchester: https://www.greentechrenewables.co.uk/service-area/manchester/air-source-heat-pump-installation ## How Greentech handles planning Every Greentech survey includes the MCS 020(a) noise calculation and a positioning (https://www.greentechrenewables.co.uk/ashp/what-is-the-best-side-of-the-house-to-put-a-heat-pump-on) plan for the outdoor unit. If your property needs planning permission — for example a listed building or a street-facing wall in a conservation area — we tell you before you commit and can help with the application. The Boiler Upgrade Scheme grant (https://www.greentechrenewables.co.uk/boiler-upgrade-scheme-bus) still applies either way. ## Frequently Asked Questions ### Is the 1m rule for heat pumps still in force? No. In England it was removed on 29 May 2025. A heat pump can now be closer than 1 metre to the boundary as long as the installation passes the MCS 020(a) noise assessment and meets the other permitted development conditions. ### Can a heat pump go right next to my neighbour's fence? It can, if the noise calculation at your neighbour's nearest door or window comes out at 37 dB(A) or lower. Placing a unit very close to a boundary makes that harder to achieve, so your installer may still recommend a different spot. ### What is MCS 020(a)? It's the noise calculation standard that air source heat pumps in England must meet to count as permitted development since 29 May 2025. It replaced the original MCS 020 in England. ### How many heat pumps can I install without planning permission? Two on a detached house and one on any other type of home, each with an outdoor unit of up to 1.5 m³ (0.6 m³ for flats). ### Do I need planning permission in a conservation area? Only if the unit would be on a wall or roof facing a road, or nearer the road than the house. Units at the back or side of the property are usually permitted development if they meet the other conditions. Listed buildings always need consent. ### Do the new rules apply in Wales or Scotland? No. These changes apply to England. Wales, Scotland and Northern Ireland have their own permitted development rules, so check with your local planning authority. ## Related Guides & Resources ### Heat Pump Systems Samsung & Vaillant air source heat pump installation. https://www.greentechrenewables.co.uk/heat-pumps ### BUS Grant (£7,500) How to claim your Boiler Upgrade Scheme grant. https://www.greentechrenewables.co.uk/boiler-upgrade-scheme-bus ### How Heat Pumps Work Understand the technology behind air source heat pumps. https://www.greentechrenewables.co.uk/ashp/how-do-heat-pumps-work ### Radiators for Heat Pumps Sizing guide, upgrade costs, and radiator compatibility. https://www.greentechrenewables.co.uk/ashp/radiators-for-heat-pumps ### Heat Pump Costs Full pricing guide for heat pump installation. https://www.greentechrenewables.co.uk/ashp/how-much-does-a-heat-pump-cost ### Are Heat Pumps Worth It? Honest analysis of heat pump value for UK homeowners. https://www.greentechrenewables.co.uk/ashp/is-a-heat-pump-worth-it-in-the-uk ### ASHP Installation Manchester MCS-certified heat pump installers serving Greater Manchester. https://www.greentechrenewables.co.uk/service-area/manchester/air-source-heat-pump-installation ### Solar Panels Combine solar with a heat pump for maximum savings. https://www.greentechrenewables.co.uk/solar-panels ### Government Grants All available grants for renewable energy upgrades. https://www.greentechrenewables.co.uk/grants ### Get a Free Quote Book a free, no-obligation home survey. https://www.greentechrenewables.co.uk/free-quote ## Ready to Install a Heat Pump? Book a free survey and we'll tell you exactly where your heat pump can go — including the noise calculation. Book Free Assessment: https://www.greentechrenewables.co.uk/heat-pumps#heat-pump-estimate Call 0333 577 7010: 03335777010 ## Accreditations Image: Our Accreditations: HIES Consumer Code, TSI Approved Code, TrustMark Government Endorsed Quality, Green Deal Approved, MCS Certified, NAPIT (https://www.greentechrenewables.co.uk/assets/solar-accreditations-CbjEg9cO.png) Public Liability Insurance – Tradesman Saver £5,000,000 – GREE55TR01 Employers Liability Insurance – Tradesman Saver £10,000,000 – GREE55TR01 Professional Indemnity – Tradesman Saver £250,000 – GREE55TR01 ## Structured data ```json [ { "@context": "https://schema.org", "@type": "LocalBusiness", "@id": "https://www.greentechrenewables.co.uk/#localbusiness", "name": "Greentech Renewables Ltd", "alternateName": "Greentech Renewables", "image": "https://www.greentechrenewables.co.uk/logo.png", "description": "MCS-certified solar panel, battery storage, heat pump and EV charger installer based in Greater Manchester, serving the North West and the UK. 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