Heat pump permitted development rights let you install without full planning permission
If you are considering replacing your gas boiler with a heat pump, the question of planning permission often arises. Many homeowners assume any external equipment change requires a full application to the local council.
Under permitted development (PD) rights, air-source heat pumps (ASHPs) can be installed without a planning application if they meet specific size, siting, and noise limits. The rules were relaxed in England from December 2023 and remain in effect in 2026, removing the previous 1-metre-from-property-boundary requirement for most homes (GOV.UK, 2026).
This article explains exactly what the 2026 rules allow and where they still fall short, so you can assess your property without needing a planning consultant.
The property and location rules that determine if you qualify
PD rights apply only to houses, not flats, maisonettes, or commercial buildings. The heat pump must be installed within the curtilage of the dwelling, meaning the garden or driveway immediately around your house (GOV.UK, 2026).
The outdoor unit must be at least 1 metre from any property boundary. However, if your house is detached from the boundary by a road, pavement, or other permanent obstacle, this distance requirement does not apply. The unit must not be sited on a roof that faces a road, nor on a wall that fronts a highway (Planning Portal, 2026).
Two key variables determine whether your location qualifies. First, whether your property is a house or a flat. Second, whether your garden or driveway directly abuts a neighbour’s boundary without a road or pavement in between.
The size and noise limits that your chosen model must meet
The heat pump’s outdoor unit must have a volume no greater than 0.6 cubic metres. This is roughly equivalent to a box measuring 1.2 metres by 0.8 metres by 0.6 metres, which covers most standard domestic models (MCS 020, 2026).
The noise level must not exceed 42 dB(A) measured at 1 metre from the outdoor unit. If the unit is installed on a flat roof, the limit rises slightly to 45 dB(A) at 1 metre. These noise limits are absolute, meaning if your chosen model produces 43 dB(A) at 1 metre, you must apply for full planning permission (MCS 020, 2026).
Most modern heat pumps from major manufacturers comply with the 42 dB(A) limit at full load, but cheaper or older models may not. Always check the manufacturer’s datasheet for the declared sound power level before purchasing.
Quick numbers what the 2026 rules mean for your installation
| Rule / Requirement | Details | Source |
|---|---|---|
| Property type | Detached or semi-detached houses qualify; flats and maisonettes do not | GOV.UK, 2026 |
| Minimum boundary distance | 1 metre from boundary (0 metres if separated by road or pavement) | Planning Portal, 2026 |
| Maximum unit volume | 0.6 cubic metres (roughly 1.2m x 0.8m x 0.6m) | MCS 020, 2026 |
| Maximum noise level | 42 dB(A) at 1 metre (45 dB(A) on flat roof) | MCS 020, 2026 |
| Typical ASHP cost range | £8,000–£14,000 installed | Energy Saving Trust, 2026 |
| Potential annual saving vs. gas boiler | £200–£500 depending on tariff and insulation | Ofgem, 2026 |
What the 2026 rules do NOT cover and when you still need full planning
PD rights do not apply in conservation areas, Areas of Outstanding Natural Beauty (AONBs), World Heritage Sites, or on listed buildings (Grade I, II*, or II). For these properties, you must submit a full planning application regardless of the heat pump’s size or noise level (Historic England, 2026).
Flats, maisonettes, and commercial properties are excluded entirely from PD rights for heat pumps. Ground-source heat pumps have separate PD rules with a smaller footprint requirement and no noise limit, but they still require planning if the trenching or borehole exceeds certain dimensions (Planning Portal, 2026).
If your installation fails any single rule, whether noise, boundary distance, or siting, you must submit a full planning application to your local planning authority (LPA). This process typically takes 8–13 weeks and costs £258 in 2026 (GOV.UK, 2026).
The direct answer can you install a heat pump without planning permission in 2026?
Yes, for most detached and semi-detached houses in England, if the unit is under 0.6 cubic metres, quieter than 42 dB(A), at least 1 metre from the boundary, and not on a roof or wall facing a road. No, if your property is a flat, listed, in a conservation area, or the unit fails any of the size, noise, or siting rules (GOV.UK, 2026).
If your property qualifies, you do not need to notify your local council before installation. However, you must keep the commissioning certificate and MCS documentation on file in case a neighbour or enforcement officer queries the installation later.
How to choose the quietest heat pump for your garden
How to verify your installer and certify the installation for PD rights
Your installer must be MCS-certified under the Microgeneration Certification Scheme for the heat pump to qualify for the Boiler Upgrade Scheme grant, which is £7,500 in 2026, and for PD rights to apply. Without MCS certification, the installation does not automatically benefit from PD rights and may require a full planning application (Ofgem, 2026).
You can check the MCS register online at mcsdirectory.com or TrustMark at trustmark.org.uk for certified installers. Both are government-endorsed schemes that verify installer competence and insurance. The installation must comply with MCS 020 for noise and MCS 010 for installation standards, and the installer must provide a commissioning certificate upon completion (MCS, 2026).
Boiler Upgrade Scheme 2026: full eligibility and application guide
Keep all paperwork, including the MCS certificate, commissioning report, and manufacturer’s noise data sheet, in your home file. If a neighbour complains about noise or siting, you may need to prove compliance within 21 days of a council request.
Frequently Asked Questions
No, you can install an air-source heat pump under permitted development rights if your property is a house and the unit meets size, siting, and noise limits set by GOV.UK (2026).
The outdoor unit must have a volume no greater than 0.6 cubic metres, roughly a box of 1.2m x 0.8m x 0.6m, as per MCS 020 (2026).
The unit must be at least 1 metre from any property boundary, unless your house is detached by a road, pavement, or permanent obstacle (Planning Portal, 2026).
The noise level must not exceed 42 decibels measured 1 metre from the nearest neighbour's dwelling, as per MCS 020 (2026).
No, the unit must not be sited on a roof that faces a road or on a wall that fronts a highway under permitted development rules (GOV.UK, 2026).
