Most of the work is indoors, so the question is really about the outdoor unit. In England, many outdoor units on houses can be installed without a planning application, under what are called permitted development rights. This guide covers the main points. It is general information, not legal advice, and your council has the final say.
Systems that heat as well as cool
Modern split air conditioning is a type of air source heat pump: the same unit heats in winter and cools in summer. Outdoor units for air source heat pumps can be permitted development, but the rules do not cover units used only for cooling. Every system we fit can heat as well as cool.
The main conditions
According to the government's Planning Portal, an outdoor unit is only permitted development if it meets all of these:
- Size. No bigger than 1.5 cubic metres on a house, or 0.6 cubic metres on a block of flats. A typical home outdoor unit is far smaller than this.
- Noise. The installation must comply with the MCS 020 noise standard, which limits how loud the unit can be at a neighbour's window.
- How many. On a detached house, the first two units can be permitted development. On a semi-detached or terraced house, only the first one.
- Roofs. Not on a pitched roof. On a flat roof, every part must be at least one metre from the edge.
- Walls facing a road. Not on a wall facing a road above ground-floor level.
- Appearance. Sited to keep its effect on how the building looks, and on neighbours, to a minimum.
- Flats. The rights cover blocks made up only of flats, with no shops or offices in the building.
When you will need to ask first
- Listed buildings. Permitted development does not apply. You will need consent from your council.
- Conservation areas. The unit cannot go on a wall or roof facing a road, or closer to the road than the house itself.
- Article 4 areas and planning conditions. Some areas and newer homes have had permitted development rights removed. Your council can tell you.
- Cooling-only units, or more units than the limits above.
- Flats you lease. Even where planning is not needed, you will usually need permission from your freeholder or management company.
How we help
At your free survey we look at where the outdoor unit can go, check it against these rules and choose a position that keeps noise away from neighbours' windows. If anything needs checking with the council, we tell you before you commit. See our installation page or get an instant estimate with our quote builder.
Source: Planning Portal, air source heat pumps (England). Rules can change, so check with your local council if you are unsure.