Is Planning Permission Required for Air Conditioning In London? A Homeowner’s Guide

As London summers become warmer and more unpredictable, more homeowners are considering air conditioning to improve comfort, sleep and overall quality of life. But before installing a system, one important question often arises: is planning permission required for air conditioning in London?

The answer isn’t always straightforward. It depends on the type of system, the property, its location and the planning restrictions that apply.

In many cases, qualifying air-source heat pumps that provide both heating and cooling can be installed under permitted development rights without a full planning application. However, this depends on several factors, including the size and position of the unit, whether the property is in a Conservation Area, and whether it is listed or leasehold.

Cooling-only air conditioning systems do not qualify for the Class G permitted development rights that apply to air-source heat pumps. Flats and shared buildings can also introduce additional layers of approval beyond standard planning rules.

Understanding what applies to a property is essential before moving forward with installation. Getting it wrong can lead to delays, enforcement notices, or costly changes after the fact.

In this guide, we’ll explain how planning permission works for residential air conditioning in London, when permission isn’t required, when it is, and what practical steps to take before proceeding.

What is planning permission?

Planning permission is formal approval from the relevant local council allowing certain building works or changes to a property. In London, each borough acts as the local planning authority and is responsible for deciding whether proposed alterations are acceptable.

The purpose of planning permission is to ensure that developments are appropriate for their surroundings. Councils consider factors such as:

• Visual impact
• Effect on neighbours
• Noise
• Environmental considerations
• Overall character of the area

When it comes to air conditioning in London, the key issue is usually the external condenser unit. While the equipment may be mounted on a wall, roof, balcony, or located elsewhere in a garden, careful technical consideration is required to ensure the visual impact is not overwhelming. In some cases, this means planning permission must be obtained before installation.

However, not every installation requires a planning application. Many residential systems fall under what are known as permitted development rights, which allow certain types of work to be carried out without submitting a full planning application, provided specific conditions are met.

It is important to distinguish between cooling-only and an air-source heat pump that provides both heating and cooling. Class G permitted development rights can apply to qualifying air-source heat pumps used for heating and cooling, but not to systems used solely for cooling.

Understanding the distinction between full planning permission and permitted development is the first step in determining what applies to a London home.

At a glance: Does your property need planning permission?

The answer depends on both what system you are installing and where you are installing it.

These rules relate to England, and the Class G permitted development rights for qualifying air-source heat pumps. A cooling-only air conditioning system should not be assumed to qualify under Class G. Planning permission, listed building consent, building regulations approval and private property consent are separate matters.

Permitted development rights: When permission isn’t required

In many cases, homeowners in London can install a qualifying air-source heat pump without applying for full planning permission thanks to permitted development rights.

Permitted development rights allow certain types of building work and alterations to be carried out without a formal planning application, provided specific conditions are met. For air-source heat pumps, these rules can apply to qualifying installations on houses and blocks of flats in England.

Under the changes introduced in May 2025, the main Class G criteria include the following:

• The outdoor compressor unit, including its housing, must not exceed 1.5m³ for a house or 0.6m³ for a block of flats.
• A detached house can have up to two air-source heat pumps, while a semi-detached or terraced house and a block of flats can have up to one under Class G.
• The system must not be used solely for cooling. It must be a qualifying air-source heat pump that provides heating, with heating and cooling functionality permitted.
• The unit must not be installed on a pitched roof.
• On a flat roof, the unit must be at least one metre from the external edge of the roof.
• Highway-facing wall restrictions depend on the location. In a Conservation Area or World Heritage Site, additional positioning restrictions apply. Outside these areas, a unit cannot be installed on a highway-facing wall above ground-floor storey level.
• The unit must be sited, so far as practicable, to minimise its effect on the external appearance of the building and the amenity of the area.
• The installation must comply with the applicable MCS Planning Standards, including the relevant sound-calculation requirements under MCS 020(a).

If all applicable conditions are satisfied, a planning application may not be required.

The previous general one-metre boundary restriction for air-source heat pumps was removed in 2025. However, the separate one-metre restriction from the external edge of a flat roof remains. The location of the unit still matters for noise, visual impact and neighbour amenity.

Permitted development rights do not automatically apply in every situation. They are not available under Class G for air-source heat pumps installed on a listed building or within its curtilage, and they may be restricted or removed by an Article 4 Direction or relevant planning conditions.

Conservation Areas do not automatically remove Class G permitted development rights. Qualifying installations can still benefit from permitted development in these areas, provided the applicable conditions and additional positioning restrictions are met.

Flats can also benefit from Class G permitted development rights, although leaseholder, freeholder and management-company consent may still be necessary.

When planning permission is required for air conditioning

While many residential installations fall under permitted development, there are situations where planning permission will need to be applied for before installing air conditioning in London.

1.   The property is in a Conservation Area

Homes located within Conservation Areas are subject to additional planning considerations to preserve the character and appearance of the neighbourhood.

Being in a Conservation Area does not automatically mean planning permission is required for a qualifying air-source heat pump. Class G permitted development can still apply, but the rules impose additional restrictions on where the unit can be installed. For example, installations on walls or roofs facing a highway, and installations positioned closer to a highway than the nearest part of the building, may not qualify.

An applicable Article 4 Direction may also remove some or all relevant permitted development rights. The property's exact location and the scope of any direction should therefore be checked before installation.

Where planning permission is required, the appearance of the installation may be an important consideration.

Where possible, external equipment should be positioned discreetly and designed to minimise its impact on the appearance of the property. This could involve:

• Positioning equipment away from prominent elevations
• Using appropriate screening
• Minimising visible pipework and trunking
• Choosing an appropriate finish or colour
• Avoiding important architectural features

2.   The home is a listed building

If the property is listed, Class G permitted development rights do not apply to the installation of an air-source heat pump on the listed building or within its curtilage. However, Listed Building Consent is not automatically required for every type of work: it depends on whether the proposed alterations affect the building's special architectural or historic interest. Planning permission may also be required.

Listed buildings are protected for their architectural or historic significance, and councils take a careful approach to external changes, including plant equipment such as air conditioning units.

The design and location of an outdoor unit are therefore particularly important.

There is no single design that guarantees consent, but proposals can be more sympathetic where they:

• Position external units away from prominent elevations where possible
• Use existing plant areas or discreet roof locations where appropriate
• Incorporate suitable screening
• Minimise visible pipework
• Avoid damaging important historic fabric
• Use discreet fixings and finishes
• Avoid important architectural details

For listed properties, it is therefore worth considering the planning and heritage requirements before finalising the air conditioning design.

3.   The installation doesn’t meet permitted development criteria

Planning permission may be required if the proposed installation does not meet the relevant permitted development conditions. For a qualifying air-source heat pump, examples include:

• Exceeding the applicable unit size limit of 1.5m³ for a house or 0.6m³ for a block of flats
• Installing more units than permitted: two for a detached house, or one for a semi-detached or terraced house or a block of flats
• Installing the unit on a pitched roof
• Installing the unit within one metre of the external edge of a flat roof
• Installing the unit in a prohibited position in relation to a highway, taking account of whether the property is in a Conservation Area or World Heritage Site
• Failing to meet the applicable MCS Planning Standards or other relevant permitted development conditions
• Failing to meet the required siting and amenity conditions

The former general one-metre boundary restriction no longer applies. A unit's distance from a neighbouring boundary should instead be assessed in the context of noise, vibration, visual impact and the applicable planning requirements.

For cooling-only air conditioning, Class G is not available. The need for planning permission must therefore be assessed under the rules applicable to the proposed installation and property.

4.   Permitted development rights have been removed

In some cases, permitted development rights are restricted or removed altogether. This can happen in:

• New-build estates with specific planning conditions
• Properties subject to an Article 4 Direction
• Certain sensitive or high-profile locations

If property deeds or local council records show that permitted development rights have been withdrawn, planning permission must be obtained regardless of system size.

It is important to establish exactly which rights have been removed, rather than assuming that all permitted development rights are unavailable.

5.   Flats and shared buildings

Blocks of flats can benefit from Class G permitted development rights for qualifying air-source heat pumps, contrary to the common assumption that flats always require planning permission for external equipment. The applicable conditions include a maximum outdoor compressor unit volume of 0.6m³ and a limit of one heat pump for the block.

Cooling-only air conditioning systems do not benefit from these Class G rights. Their planning position must be assessed separately.

Even where permitted development applies, leasehold properties and shared buildings can introduce additional requirements. Your lease may require you to obtain permission from the freeholder or landlord before making alterations to the property.

This can be particularly important where the installation involves:

• External walls
• Roofs
• Balconies
• Communal areas
• Visible pipework
• Fixings into the building

GOV.UK confirms that leases commonly include requirements for permission before alterations are made.

The freeholder may therefore require a licence to alter or another form of written consent.

Importantly, planning permission and freeholder consent are separate. Obtaining planning permission does not automatically give a leaseholder the right to make alterations under the terms of their lease. Equally, qualifying for permitted development does not remove any obligations under the lease or the building’s management arrangements.

As planning rules can be complex and borough-specific, confirming the planning position prior to installation is essential. Submitting an application where required can prevent delays, complaints, or enforcement action later on, particularly in tightly regulated areas of London.

Noise considerations and neighbour impact

Noise is one of the key factor’s councils consider when assessing residential air conditioning in London, even under permitted development.

Outdoor condenser units produce sound when operating, and in densely built areas this can quickly become an issue if not properly managed.

For qualifying air-source heat pumps relying on Class G permitted development, the applicable MCS Planning Standards include MCS 020(a), the air-source heat pump sound-calculation standard. This uses a calculated noise assessment, including a 37dB criterion at the relevant assessment positions. Compliance should be demonstrated using the prescribed methodology rather than simply measuring noise at the neighbouring boundary.

This is different from assuming that every air conditioning installation in London is subject to one universal noise limit. The applicable requirements depend on the system, the planning route and the local authority's requirements.

Where planning permission is required, the council may request an acoustic assessment, which can consider:

• The manufacturer’s noise data for the proposed unit
• The position of the outdoor equipment
• The nearest neighbouring windows or other noise-sensitive areas
• Existing background noise levels
• Predicted noise levels at neighbouring properties
• The potential for vibration
• Proposed mitigation measures

Mitigation could include selecting quieter equipment, repositioning the unit, using acoustic screening or installing anti-vibration mounts.

Good system design makes a significant difference. Positioning the unit away from bedroom windows and boundaries, using anti-vibration mounts, and selecting a high-quality, low-noise model all help reduce impact.

In short, careful siting and professional design are essential to ensure the system runs quietly and avoids neighbour complaints.

How do London boroughs treat air conditioning applications?

One of the important things to understand about installing air conditioning in London is that the national planning rules are only part of the picture.

Individual boroughs have their own planning policies, conservation areas and Article 4 Directions, and their application requirements can vary.

Westminster

Westminster specifically identifies external air conditioning and plant within its householder application requirements and can require an acoustic report to demonstrate that noise will be acceptable.

The borough also contains extensive areas of conservation and heritage interest, making the location and appearance of external plant particularly important.

For a qualifying air-source heat pump, the national Class G conditions must be considered alongside any applicable local restrictions. A Conservation Area designation alone does not automatically remove permitted development rights.

Kensington and Chelsea

The Royal Borough of Kensington and Chelsea has extensive conservation areas and Article 4 Directions.

Its planning policies also place importance on the impact of building-services plant on neighbouring occupiers, including noise.

For properties in the borough, it is therefore important to check the property’s conservation status, any relevant Article 4 Direction and the proposed location of the external unit.

The presence of a Conservation Area does not, by itself, mean that a qualifying air-source heat pump requires planning permission. However, additional siting restrictions and any applicable removal of permitted development rights must be checked.

Camden

Camden has specific requirements for applications involving plant, ventilation and air conditioning.

The council can require a noise, vibration and ventilation assessment for applications involving the installation, alteration or replacement of air conditioning equipment.

This means that the technical and acoustic design of an installation can be an important part of the planning application, rather than simply an afterthought.

The key point is that London does not have one single approach to air conditioning. The specific borough, property and planning constraints should be checked before installation.

Planning permission and Calibre support

Navigating planning rules in London can feel complex, particularly in Conservation Areas, listed buildings, or apartment blocks. That’s why early-stage guidance is essential.

At Calibre, planning considerations are built into the design process from the outset. This involves specifying a fully bespoke system designed not only to comply with all relevant guidelines but also to meet size, noise, and performance requirements. From initial concept through to final design, every element is planned to ensure the system sits discreetly and functions optimally within the property.

Where planning permission is required, Calibre manages the full planning application process, helping homeowners navigate the requirements from initial assessment through to submission. This can include coordinating the preparation of technical specifications, acoustic information, layout drawings and any other supporting documentation needed for the application.

For more sensitive properties, careful system selection and sympathetic positioning help minimise visual impact and support a well-prepared planning proposal.

By managing planning requirements alongside system design, Calibre helps homeowners address compliance early, reduce the risk of avoidable delays and coordinate the steps needed to move towards installation. Where freeholder or management-company consent is also required, this can be identified as a separate part of the process.

Your air conditioning planning questions, answered

Planning rules can vary depending on your property, location and the type of system you are installing. Here are answers to some of the most common questions homeowners ask about air conditioning planning permission in London.

Do I need planning permission for air conditioning in a flat?

Not necessarily. A qualifying air-source heat pump that provides heating and cooling can benefit from Class G permitted development rights when installed on a block of flats, provided the relevant conditions are met. The outdoor compressor unit must not exceed 0.6m³, and the permitted number is one heat pump for the block.

Cooling-only air conditioning systems do not benefit from Class G permitted development rights and must be assessed separately.

Leaseholders may also need freeholder or landlord consent under the terms of their lease.

Can I install air conditioning in a conservation area?

Potentially, without planning permission. A Conservation Area does not automatically remove Class G permitted development rights for qualifying air-source heat pumps.

The type of system, location of the outdoor unit and any applicable Article 4 Direction should be checked before installation. Additional restrictions apply to the positioning of units in Conservation Areas, particularly in relation to highways. The visual impact of external equipment can also be an important consideration where planning permission is required.

Can you put air conditioning in a listed building?

Potentially, but careful assessment is required.

Class G permitted development rights do not apply to air-source heat pumps installed on a listed building or within its curtilage. Listed Building Consent may be required if the proposed work affects the building's special architectural or historic interest, and planning permission may also be necessary. Consent is not automatically required for every type of work.

The location and design of the outdoor equipment should be carefully considered to minimise its impact on the building and its historic fabric.

How close to a neighbour's boundary can an outdoor unit go?

The general one-metre boundary restriction for air-source heat pumps under Class G was removed in May 2025. There is no longer a universal one-metre boundary setback under that rule.

However, the position of the unit still matters because noise, visual impact and the effect on neighbouring properties can all be relevant planning considerations. The separate one-metre restriction from the external edge of a flat roof remains in force.

How loud is an air conditioning unit allowed to be?

There is no single noise limit that applies to every air conditioning installation in London.

For qualifying air-source heat pumps installed under Class G permitted development, MCS 020(a) provides the prescribed sound-calculation methodology, including a calculated 37dB criterion at the relevant assessment positions. Other installations may be subject to different planning requirements, including local authority noise criteria or an acoustic assessment.

An acoustic assessment may be required where planning permission is being sought, particularly where neighbouring properties could be affected.

How long does planning permission for air conditioning take?

Most planning applications are normally decided within around eight weeks, although more complex applications can take longer.

The overall process may take longer if drawings, acoustic assessments, heritage information or freeholder consent are also required.

Where Calibre manages the planning application, the team can coordinate the required supporting information and submission. The overall timescale will still depend on the application requirements and the council's decision-making process.

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Key takeaways for London homeowners

Planning permission for air conditioning in London depends on the system, property type and location. Qualifying air-source heat pumps providing heating and cooling can benefit from permitted development rights, including in some Conservation Areas and blocks of flats, provided all relevant conditions are met. Cooling-only systems do not qualify under Class G.

The updated rules allow units of up to 1.5m³ for houses and 0.6m³ for blocks of flats, subject to limits on the number of units, positioning and noise. Listed buildings, Article 4 Directions and leasehold requirements may introduce additional considerations.

Calibre can manage the full planning application process where permission is required, helping homeowners address compliance early and avoid unnecessary delays.

Contact Calibre for expert guidance and a discreet, compliant air conditioning solution tailored to your London property.