Period home air conditioning
By Airva Editorial Team · Checked against published UK guidance · Updated
Air conditioning in a period home is a siting problem before it is an engineering problem. The pipework and the units are routine; what you may fix to the outside of the house, and where, decides whether the project needs an application and how it looks from the street.
If the house is listed, permitted development does not apply anywhere within its curtilage, so an outdoor unit needs planning permission as well as listed building consent [1]. Our listed building guide covers the consent process and the options a conservation officer is likely to accept. The rest of this page is about unlisted period homes.
Conservation areas: rights survive, but siting is constrained
If the building is unlisted but sits in a conservation area or World Heritage Site, permitted development rights remain, with a specific restriction. The outdoor unit must not be installed on a wall or roof fronting a highway, and must not be nearer to any highway bounding the property than any part of the building [1].
In practice that pushes the unit to a rear elevation, a courtyard, a side return or a light well, which is where most period properties want it anyway. Two things to check alongside:
- Article 4 directions, which local authorities apply street by street in historic areas and which can remove permitted development rights entirely [1]. A neighbour's installation proves nothing about your position.
- The ground-floor rule elsewhere. Outside conservation areas, the unit must not go on a wall above ground-floor storey level if that wall fronts a highway [1].
The main tests, all of which must pass. The full Class G checklist adds further conditions — existing wind turbines, removal when no longer needed, and siting to minimise impact. England only: Scotland, Wales and Northern Ireland set their own thresholds. The 1 metre boundary rule was removed in 2025; the sound calculation now does that work instead.
What the 2025 changes did for period properties
The permitted development regime was amended on 29 May 2025 in ways that help older houses specifically [2]:
| Change | Why it matters in a period property |
|---|---|
| The 1m boundary rule was removed | Narrow side returns and small courtyards, the classic Victorian terrace positions, are now viable where the sound assessment allows |
| Volume limit raised to 1.5 m³ | Larger multi-split condensers now fit, so one unit can serve several rooms instead of several units cluttering an elevation |
| Two units permitted on detached houses | Useful on larger period detached properties |
The trade-off is that the sound calculation now does the work the boundary rule used to do crudely. Compliance is demonstrated through MCS 020(a), which was clarified in 2025 on what counts as a solid barrier, how the assessment position is determined, and what counts as a reflective surface [2]. That last point matters in a narrow brick-walled side return, where sound bounces between two hard surfaces. The full rules are in our planning permission guide.
Not sure what you can fit without permanent changes? The planner compares the options and says what to keep and what to change, in about a minute. Plan my home → or watch it work (24 s) ↓
Siting discreetly
Positions that tend to work:
- Rear elevations and back additions. The flat roof of a Victorian rear extension is often ideal: short pipe runs, out of sight from the street, no scaffold.
- Light wells and basement areas, common in Georgian and early Victorian townhouses.
- Ground-level stands behind planting or a wall, rather than a bracket high on a visible elevation.
- Set back from the parapet on a flat roof, so nothing is visible from street level.
Colour-matched trunking, pipework routed through redundant chimney flues or existing service voids, and grilles chosen to suit the room all help as much as the position. Our external unit guide covers siting in general, and air conditioning for old houses covers internal routing in detail.
Where there is no outdoor position
Some period houses, and flats converted from them, have no compliant position at all. The options are then a through-wall monobloc, which still means two large holes in the wall, or a portable. Our guide to systems without an outdoor unit sets out what each actually does.
Cost
Installation costs much the same as in any comparable house, £1,500–£3,500 for a single room, more where pipework has to be concealed through original fabric. The premium in a period home is usually careful, slow internal routing rather than the equipment. See the cost guide.
Frequently asked questions
What if the house is listed? Permitted development does not apply within the curtilage of a listed building, so you need planning permission and listed building consent [1]. Our listed building guide covers both.
What about a conservation area? Permitted development rights survive, but the unit cannot go on a wall or roof fronting a highway, nor nearer to a bounding highway than any part of the building [1]. Check for an Article 4 direction as well.
Does the 1m boundary rule still apply? No. It was removed on 29 May 2025 [2]. Siting close to a boundary is now governed by the MCS 020(a) sound calculation instead, which helps in narrow side returns.
Can pipework be hidden in a period house? Usually. Redundant chimney flues, alcove cupboards, floor voids and existing service routes all help, and colour-matched trunking handles the rest. See our old houses guide.
Start an enquiry
Tell us about the property, whether it is in a conservation area, and where you think a unit might go. We'll review your requirements and match you with a suitable installer operating in your area: start your enquiry.