Do I need planning permission for solar panels or a heat pump?

These two installations get the same shape of answer: a national permitted development right, hedged with conditions that are specific and that have been revised more than once as government policy has changed. That is precisely why no honest guide should quote a distance or a decibel figure at you — the useful thing is knowing which conditions exist and where the current version lives.

Step by step

1. Check the property first, as always.Flats, listed buildings, conservation areas, National Parks and Article 4 areas all change the answer. Solar on the principal elevation of a house in a conservation area, and almost any external plant on a listed building, are the classic cases where an application is required.
2. Check the solar conditions.Roof-mounted panels have conditions on how far they may project from the roof plane, on not projecting above the highest part of the roof, on siting to minimise the effect on the appearance of the building and the amenity of the area, and on removal when no longer needed. Stand-alone ground arrays have their own separate limits.
3. Check the heat pump conditions.Air source heat pump permitted development in England is conditional on siting, on the unit meeting the relevant planning standard for noise, on the number of units, and on removal when no longer needed. These conditions have been amended in recent years, so read the current version.
4. Use a certified installer.Microgeneration Certification Scheme certification, or an equivalent recognised scheme, is normally what grant schemes and export tariffs require, and it is also the practical route to the noise assessment a heat pump's permitted development condition depends on.
5. Deal with the building regulations side separately.Solar adds load to a roof, which is a structural question, and the electrical work is notifiable. A heat pump involves controlled services — heating, hot water, electrical work and sometimes a hot water cylinder — all of which are building regulations matters.
6. Check the electrical connection and the network operator.Generation and heat pump installations usually have to be notified to, and in some cases approved in advance by, the distribution network operator. Your installer normally handles this, but confirm in writing that they are doing it.
7. Think about the neighbour before the noise complaint.A heat pump close to a neighbouring bedroom window is a statutory nuisance risk even where it is permitted development. Siting decisions are far cheaper than moving a unit after a complaint.
8. Collect the certificates at the end.Scheme certificate, electrical installation certificate, building regulations compliance certificate, commissioning records and the warranty registration. These are also what a future buyer and any grant administrator will ask for.

Tips

• Listed building consent can be required for solar even where planning permission is not, because it turns on the effect on the building's special interest, including on outbuildings and on the setting.
• Permitted development conditions for heat pumps and solar in Scotland, Wales and Northern Ireland are set separately. Do not use an England answer elsewhere.
• A flat roof array, a wall-mounted array and a ground-mounted array are three different permitted development questions. Do not assume the roof answer covers them.

Common mistakes

• Assuming a listed building is treated like any other house — Unauthorised alteration to a listed building is a criminal offence, and external plant and panels are exactly the kind of alteration that requires consent.
• Leaving the network operator notification to chance — An unregistered generation or heat pump connection can cause problems later with export payments and with the operator, and the responsibility ultimately sits with the property owner.

Questions people ask