Planning
Solar Panels and Heat Pumps: Do You Need Planning Permission?
Solar panels and air source heat pumps are usually permitted development — and the heat pump rules were relaxed in 2025 — but conservation areas and listed buildings change the picture. This guide sets out the limits.
The short answer
For most houses, both solar panels and an air source heat pump can be installed under permitted development, with no planning application — and the heat pump rules were made more generous in 2025. The main exceptions are listed buildings, where consent is needed, and conservation areas, where some positions are restricted. As with all permitted development, the limits have to be met, and they do not apply to flats in the same way as to houses.
Solar panels
Panels on the roof of a house are permitted development provided they do not project more than 200mm from the roof slope, and are not fitted above the highest part of the roof (excluding the chimney). On a flat roof, the equipment must not stand more than 600mm above the highest part of the roof. In a conservation area or World Heritage Site, panels must not be fitted to a wall that fronts a highway — but roof panels are usually still permitted development. A single ground-mounted array can also be permitted development within limits (broadly, no more than 9 square metres, up to 4 metres high and set at least 5 metres from the boundary). Panels on a listed building need listed building consent.
Air source heat pumps — the 2025 changes
The permitted development rules for air source heat pumps were relaxed in England in 2025. The old requirement to site the unit at least one metre from the property boundary was removed; the size limit for the outdoor unit was increased to 1.5 cubic metres for a house (0.6 cubic metres for a flat); and detached houses may now have up to two heat pumps rather than one. The installation must still meet the MCS planning standard for noise (MCS 020), which controls the noise at neighbouring windows.
Conservation areas and listed buildings
The rights are narrower on protected buildings and land. Permitted development for a heat pump does not apply within the curtilage of a listed building, or on a scheduled monument, and in a conservation area the siting of a heat pump or solar equipment can be restricted — typically so that it is not on a wall or roof slope facing a highway. Because so much of prime London is designated, it is worth confirming the position for your property before ordering equipment, and factoring any application into the programme.
Frequently asked questions
Do I need planning permission for solar panels?
Can I put solar panels on a house in a conservation area?
Do I need planning permission for an air source heat pump?
What changed for heat pumps in 2025?
What about solar panels or a heat pump on a listed building?
Is there a noise rule for heat pumps?
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