The short answer
Fitting air conditioning to a listed building needs listed building consent, and permitted development doesn't cover it. In England, conservation areas and other protected areas still have permitted development, but with stricter rules, including on walls and roofs facing a road.
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Protected buildings and areas are where the planning rules for heat pumps change most, and where how a system is fitted matters as much as where the outdoor unit goes. The rules on permitted development described here are for England. Wales, Scotland and Northern Ireland run their own systems for listing and protected areas, so check with the local council there.
Finding out whether your home is protected
Your local council can tell you whether your home is listed, whether it's in a conservation area, and whether any other restriction applies, such as an Article 4 direction. The searches carried out when you bought the home may also show this.
Each nation keeps an official list of listed buildings that can be searched. Conservation areas are usually designated by local councils, which normally publish maps of them.
Listed buildings
Permitted development doesn't cover heat pumps on listed buildings, and fitting one needs listed building consent from the council. This applies whatever the grade of listing, and the consent has to be in place before the work is done.
Listing normally covers the whole building, inside as well as out. That means consent can be needed for more than the outdoor unit:
- holes through walls for pipework
- pipe and cable routes, inside and outside
- indoor units fixed to historic walls or near features such as cornices and panelling
- brackets and fixings on the outside of the building
Because permitted development doesn't apply, planning permission is usually needed as well. The council can confirm what's required for a particular building, and the two applications can often be made together.
Conservation areas and other protected areas
In a conservation area or a World Heritage Site, permitted development still applies, but the rules are stricter. For example, a unit on a wall or roof that faces a road isn't covered at any height. The other conditions, including the limits on number, size and noise, still apply. Do you need planning permission? sets them out.
Some conservation areas also have an Article 4 direction, which removes some permitted development rights. Where one applies, planning permission may be needed for work that would otherwise be allowed, so it's something to check with the council before planning an installation.
A home that isn't listed can still sit in a conservation area, and a listed building can sit inside one. Where both apply, both sets of rules have to be met.
Reducing the impact on an older building
When a council considers an application, it looks at how visible the installation will be and how much it affects the building's historic character. Much of that comes down to decisions about the details.
| Part of the job | What to consider |
|---|---|
| Outdoor unit | Where it can be seen from, and whether a ground stand avoids fixing to the building |
| Pipe route | Pipework on show outside, or disturbance inside |
| Holes through walls | Historic material can't be put back |
| Fixings | Mortar joints are easier to repair than brick or stone |
| Indoor units | Plasterwork, panelling and other features nearby |
A few points come up often:
- Out of sight. Rear walls and gardens, away from the street, usually have the least visual impact. Where the outdoor unit can go covers the practical limits on position.
- Ground or wall. A unit on a ground stand avoids brackets on historic masonry. Wall brackets and ground stands compares the two.
- Pipe length and route. Keeping the indoor and outdoor units close shortens the run and the amount of trunking. Refrigerant pipework explained explains the limits on length and height.
- Noise. The noise standard applies here as everywhere else, and a position chosen to be hidden from view still has to pass it.
An application usually needs drawings or photos showing where the units, pipes and fixings will go. A good installer will survey the building first and can help with that information, but the decision rests with the council.
Related guides
- Do you need planning permission?Usually not in England, where air-to-air heat pumps that aren't used only for cooling count as permitted development if conditions on number, size, position and noise are met. Listed buildings, flats and protected areas follow different rules.
- Where the outdoor unit can goAn outdoor unit needs a firm fixing, free airflow, service access and somewhere for defrost water to drain. On a house in England it can usually go on a wall, the ground or a flat roof without planning permission if set conditions are met.
- Refrigerant pipework explainedTwo insulated copper pipes carry refrigerant between the indoor and outdoor units. They are joined at each unit, tested for leaks and cleared of air before use, and their length and route affect how the job looks and whether extra refrigerant is needed.
- Noise rules and your neighboursIn England, a heat pump fitted without planning permission must be no louder than 37 dB(A) at 1 metre from a neighbour's nearest habitable-room window or door, worked out with the MCS 020(a) calculation. Councils can also investigate noise complaints separately.