After three UK heatwaves in a matter of weeks, more Brighton & Hove homeowners are looking at ways to keep bedrooms, loft conversions and glazed living spaces comfortable. Recent headlines have also caused confusion over whether domestic air conditioning is “banned”.
It is not. The government has confirmed that air conditioning can be installed in both new and existing homes. However, there is no single answer on planning permission: it depends on the type of system, the building and the position of any outdoor unit.
The short answer
- A portable indoor air conditioner will not normally need planning permission because it does not permanently alter the building.
- A fixed system with an outdoor condenser may need planning permission, particularly if it is cooling-only, visually prominent or installed at a listed property.
- An air-to-air heat pump that provides both heating and cooling may be permitted development if every condition is met.
- Listed buildings, flats and homes in Brighton & Hove conservation areas need extra checks.
- A fixed installation may also need Building Regulations approval, even when planning permission is not required.
This article provides general guidance for homes in England. Always check the exact proposal before ordering equipment or starting work.
Is domestic air conditioning banned in the UK?
No. In June 2026, the Ministry of Housing, Communities and Local Government confirmed that air conditioning is not banned.
The confusion comes partly from the different rules applying to cooling-only air-conditioning systems and air-to-air heat pumps. The two can look similar from outside, but they are not treated in exactly the same way under permitted development rules.
Cooling-only air conditioning versus an air-to-air heat pump
A conventional split air-conditioning system moves heat out of a room to cool it. An air-to-air heat pump can normally reverse that process, providing cooling in summer and heating in winter.
This distinction matters. The permitted development right for an air source heat pump can cover a system that heats and cools, but the equipment must not be used solely for cooling. A cooling-only system therefore cannot rely automatically on that particular permitted development right.
That does not mean every cooling-only unit needs a planning application. Government guidance says permission is often unnecessary for a small home where the installation would not materially affect the building’s external appearance. There is, however, no blanket exemption. The safest approach is to have the exact unit and proposed location checked by Brighton & Hove City Council or a suitably experienced professional.
When can an air-to-air heat pump be permitted development?
An air-to-air heat pump may be installed without a full planning application under Class G permitted development rights, but only when all relevant limits and conditions are satisfied.
The current Planning Portal guidance for air source heat pumps includes the following points:
- From 28 May 2026, the installation must comply with the MCS 020a sound-calculation standard.
- An outdoor compressor unit, including its housing, must not exceed 1.5 cubic metres at a house or 0.6 cubic metres at a block of flats.
- One installation can normally be permitted at a non-detached house or a block of flats. Up to two may be permitted at a detached house.
- The unit must not be installed on a pitched roof. A unit on a flat roof must sit at least one metre from the roof’s external edge.
- The system must not be used solely for cooling.
- It must be positioned, as far as practicable, to minimise its effect on the building’s appearance and the amenity of the area.
- Further restrictions apply in conservation areas, at listed buildings and where permitted development rights have been removed.
“Permitted development” still has rules: it is not the same as having no planning controls. If just one condition is missed, a planning application may be required.
What changes in a Brighton & Hove conservation area?
Brighton & Hove has many conservation areas, including streets of tightly spaced terraces, flats and historic villas. An unlisted home in a conservation area may still benefit from permitted development rights, but the position of the outdoor unit is critical.
Brighton & Hove City Council’s guidance says an air source heat pump is not permitted development in a conservation area if it would be:
- on a wall or roof facing a highway; or
- nearer to a highway bounding the property than the part of the house or block of flats nearest that highway.
The equipment should be placed to minimise its effect on the building and the area. A discreet rear or side position may be easier to support than a prominent unit in the small front garden of a terrace. Screening can sometimes help, but it must not obstruct the airflow or create new noise problems.
It is also worth checking whether an Article 4 Direction or a condition on an earlier planning permission has removed normal permitted development rights.
What if the property is listed?
Permitted development rights for an air source heat pump do not apply within the curtilage of a listed building. Brighton & Hove City Council says planning permission and listed building consent are required.
The location, visibility, pipe routes, fixings and effect on historic fabric will all matter. A freestanding unit in a carefully chosen secondary location may cause less harm than equipment fixed to an important elevation, but every listed building must be assessed individually.
Do not arrange installation first and try to regularise it later. Agreeing a sensitive position at the design stage is usually much less expensive than moving equipment or repairing historic fabric.
Do flats need extra permission?
Potentially, yes. A flat owner may need to consider several separate approvals:
- Planning permission or compliance with permitted development conditions.
- Building Regulations requirements.
- The terms of the lease and written consent from the freeholder or managing agent.
- Any rules affecting alterations to communal walls, roofs, balconies or other shared parts.
For permitted development, the outdoor-unit size limit at a block of flats is lower than at a house, and only the first air source heat-pump installation on the block is normally covered. Mixed-use buildings, such as flats above a shop, are not treated in the same way as a block consisting wholly of flats.
Do Building Regulations apply?
Planning permission and Building Regulations are separate. You may need one, both or neither depending on the work.
GOV.UK lists the installation of a fixed air-conditioning system as work that may need Building Regulations approval. Electrical work, penetrations through walls, drainage for condensate and the energy performance of the system also need to be handled correctly.
Use a competent installer and confirm the Building Regulations route before work begins. Keep the product information, commissioning records and any compliance certificates, as these may be requested when the property is sold.
What about noise and neighbours?
Outdoor units contain fans and compressors, so noise and vibration should influence the design from the beginning. A unit may satisfy a simple dimensional rule yet still be poorly located beside a neighbour’s bedroom window or in a narrow lightwell that reflects sound.
If you intend to rely on permitted development for an air source heat pump, the MCS 020a assessment is an important part of demonstrating compliance. Consider:
- the manufacturer’s sound-power data;
- the distance to neighbouring habitable-room windows and doors;
- reflective walls and enclosed spaces;
- barriers or acoustic screening;
- vibration-isolating mounts; and
- whether more than one outdoor unit will operate at the same time.
A planning application may require a more detailed noise report. Good siting protects neighbours and can prevent complaints after installation.
Is there a grant for a system that heats and cools?
From 21 July 2026, eligible residential air-to-air heat-pump installations in England and Wales can receive a £2,500 Boiler Upgrade Scheme grant. The official grant notice sets out the value and categories.
The scheme is installer-led and has technical and eligibility conditions, so do not assume that every air-conditioning quotation qualifies. Ask an MCS-certified installer to confirm eligibility and make sure the proposed equipment provides heating as well as cooling.
A seven-step check before you install
- Identify the system. Is it portable, cooling-only, or an air-to-air heat pump providing heating and cooling?
- Check the property. Confirm whether it is listed, in a conservation area, a flat, or affected by an Article 4 Direction or planning condition.
- Choose the outdoor location carefully. Mark the unit, pipes, drainage and screening on an elevation or site plan.
- Assess appearance and noise. Consider views from the street and neighbours’ windows, not just convenience for the installer.
- Test every permitted development condition. Do not rely on a general statement that “air conditioning does not need planning permission”.
- Confirm other approvals. Check Building Regulations, lease/freeholder consent and installer certification.
- Keep written evidence. Where the planning position is uncertain, seek council advice or consider applying for a Lawful Development Certificate before work starts.
Frequently asked questions
Do I need planning permission for an outdoor air-conditioning unit in Brighton?
Not always. A small installation may not require permission if it does not materially affect the building’s external appearance. An air-to-air heat pump may also be permitted development if every Class G condition is met. Cooling-only units, listed buildings, flats and prominent locations need closer examination.
Can I put an air-conditioning unit on the front of my house?
This is often the most sensitive location. In a conservation area, an air source heat pump on a wall or roof facing a highway cannot use the Class G permitted development right. Elsewhere, other height, appearance and amenity restrictions may apply. A less visible rear or side location is normally worth exploring first.
Can a neighbour stop me installing air conditioning?
A neighbour cannot remove a valid permitted development right simply by objecting, but the installation must genuinely meet every condition, including sound and amenity requirements. If a planning application is needed, neighbours can comment and the council will assess relevant planning considerations such as noise and visual impact.
Does a portable air conditioner need permission?
A fully portable indoor unit will not normally need planning permission because there is no permanent external equipment. If it requires a new fixed vent, external grille or other alteration, that work may need checking—especially at a listed building or flat.
Is a Lawful Development Certificate compulsory?
The answer often turns on a few project-specific details: the equipment specification, the location of the outdoor unit and the planning status of the building.
Shear Architectural Design can review those constraints, explore a less intrusive layout and prepare drawings where an application is required. Read about our architectural design services or contact us to discuss your property.
This article is general information, not legal advice. Planning and grant rules can change, and the local planning authority determines individual proposals.