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GPDO 2015 England Permitted Development rules · statutory fees effective 1 April 2026

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Energy & EV Schedule 2, Part 14 · Part 14 Class G

Air Source Heat Pump Planning Rules (Part 14 Class G)

Air source heat pumps on houses are Permitted Development under GPDO Part 14 Class G, provided the unit meets MCS planning standards for noise and stays within the size limits. Reforms in force from 28 May 2025 removed the old 1-metre boundary rule and raised the outdoor unit limit from 0.6m³ to 1.5m³. Check your installation below.

If PD
£0
Application
£548
Decision
8 wks

Step 1 · Your project

Heat Pumps checker

0.6m³

Use the external dimensions including fan guard and casing: e.g. 1.1m × 0.9m × 0.45m = 0.45m³.

House type
Number of air source heat pumps
MCS 020(a) noise assessment result
Where will it be mounted?
1.2m
Conservation area/WHS, on a wall or roof facing a highway?
Is the house listed?

Rules reflect the GPDO 2015 (England) for houses. Flats, maisonettes, listed buildings and Article 4 areas have restricted rights. Disclaimer.

Step 2 · Live statutory assessment

Permitted Development – Part 14 Class G

Part 14 Class G

Your 0.6m³ heat pump meets the Class G conditions. No planning application is needed – your MCS installer will register the installation.

  • Unit volume 0.6m³ is within the 1.5m³ limit.
  • Noise assessment meets the MCS 020(a) standard.
ELEVATION – UNIT SIZE, BOUNDARY & NOISE
HOUSE BOUNDARY NEIGHBOURWINDOW ≤ 42 dB(A) 1.2m UNIT 0.6m³ · MAX 1.5m³

England fees & timings (from 1 April 2026)

Council application fee

£0

Part 14 Class G right

Lawful Development Certificate

£274

Optional – MCS certificate usually enough

Decision time

0 weeks

Install once designed

Applying online via the Planning Portal adds a £91 service charge (inc. VAT).

Builder & neighbour spec sheet

Export these exact limits and your answers to share with your contractor.

At a glance

Heat Pumps: the statutory limits in England

  • The installation must comply with MCS planning standards – in practice a noise assessment under MCS 020(a) at the nearest neighbouring habitable-room window.
  • Outdoor compressor unit volume (including housing) max 1.5m³ – the limit was 0.6m³ before 28 May 2025.
  • Detached houses may now have two air source heat pumps; other houses one.
  • The former requirement to be at least 1m from the boundary was removed in 2025 – noise compliance now does the work.
  • Not on a pitched roof, and not within the curtilage of a listed building or on a scheduled monument.
  • In a conservation area or WHS, not on a wall or roof that fronts a highway.

Statutory reference

Legislation summary & 2026 fee table

England statutory planning fees effective 1 April 2026. Wales, Scotland and Northern Ireland operate different regimes.

GPDO legislation and fee summary for Air Source Heat Pumps
Primary legislation Town and Country Planning (General Permitted Development) (England) Order 2015 (SI 2015/596), as amended
GPDO Schedule / Part Schedule 2, Part 14
Class Class G – installation of an air source heat pump on domestic premises
Exact reference GPDO 2015 Sch.2 Pt.14 Class G, G.1–G.2 (as amended 2025); MCS 020(a)
Standard application fee £548 – Householder planning application
Lawful Development Certificate (proposed) £274 – optional proof the works are lawful
Planning Portal service charge £91 (inc. VAT) if submitted online
Council determination period 8 weeks
Key exclusions Not available within the curtilage of a listed building or on a scheduled monument; extra restrictions in conservation areas and WHS.

Avoid enforcement

The 3 most common homeowner traps

Trap #1

Using the brochure size, not the external volume

The limit applies to the outdoor compressor unit’s external volume – width × height × depth including casing and fan guard. Twin-fan high-output units for larger homes can exceed 1.5m³, and acoustic enclosures add to the measured volume.

Trap #2

Relying on out-of-date guidance

Many websites still quote the 0.6m³ limit and the 1m boundary rule that applied before 28 May 2025. Equally, rules in Wales and Scotland differ from England. Make sure your installer’s design is based on the current English Class G wording.

Trap #3

Treating noise as an afterthought

The MCS 020(a) assessment uses the distance to the nearest neighbouring habitable-room window, reflective surfaces and any barrier. A unit tucked into a narrow side passage between two houses can fail even if it looks discreet. Ask for the calculation before you sign.

Separate legal regimes

Building Regulations vs planning permission

Planning is only one part of a compliant heat pump installation. Building Regulations and grant rules also apply:

Electrical work (Part P)
A dedicated supply is notifiable electrical work. MCS installers normally self-certify through a competent person scheme and notify Building Control.
Hot water (Part G)
Unvented hot water cylinders over 15 litres must be installed by a G3-qualified installer with appropriate discharge pipework.
System efficiency (Part L)
The system must be commissioned and sized correctly, with flow temperatures and controls meeting Approved Document L.
MCS & Boiler Upgrade Scheme
To claim the Boiler Upgrade Scheme grant the installation must be MCS certified; check the current grant level with Ofgem before you commit.

Fixing a heat pump bracket to a party wall can be notifiable under Section 2 of the Party Wall etc. Act 1996 (two months’ notice) where it involves cutting into the wall. Most installers avoid this by using a ground pad or your own external wall.

FAQs

Heat Pumps: frequently asked questions

Do I need planning permission for an air source heat pump in 2026?

Usually not. In England a heat pump is Permitted Development under Part 14 Class G if it meets MCS noise standards, the outdoor unit is no larger than 1.5m³, it is not on a pitched roof and the house is not listed. Otherwise a householder application (£548) is needed.

How close to my neighbour’s boundary can a heat pump be?

Since 28 May 2025 there is no fixed minimum distance in England – the old 1m rule was removed. The practical constraint is the MCS 020(a) noise calculation to your neighbour’s nearest habitable-room window.

Can I install two air source heat pumps?

On a detached house, yes – the 2025 changes allow up to two units. Semi-detached and terraced houses are limited to one under Permitted Development.

Does a heat pump need Building Regulations approval?

Yes, but your installer normally handles it: electrical and heating work is self-certified through competent person schemes, and Building Control is notified automatically. Keep the MCS certificate – buyers’ solicitors will ask for it.

Sources: The Town and Country Planning (General Permitted Development) (England) Order 2015 and amendments (legislation.gov.uk); MHCLG ‘Permitted development rights for householders: technical guidance’; the Town and Country Planning (Fees for Applications…) (England) Regulations 2012 as amended; Building Regulations 2010 Approved Documents; Party Wall etc. Act 1996. Last reviewed 15 October 2026. See our editorial standards and disclaimer.

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