When a Heat Pump Job needs Planning Permission: a Practical Checklist for Installers

The quote said installed by the end of the month. Nobody checked the listing, the property turned out to be Grade II, and the customer is now eleven weeks into an application they were never warned about. The delay is annoying. The part that costs you is that they found out from the council rather than from you.

Exceptions have become easier to miss precisely because there are fewer of them. The 2025 and 2026 reforms widened the default route so far that permitted development is now the assumption on most jobs. So when do you need planning permission? Four situations, and all four are visible at survey if you look.

Check these four before you price the work

Listed buildings. Permitted development doesn't apply within the curtilage of a listed building or a scheduled monument. That means a planning application and, separately, listed building consent for anything fixed into or affecting historic fabric. Listed building consent carries no application fee, which misleads people, the cost is the heritage statement, the drawings and the time. Watch the word curtilage: the coach house, the boundary wall and the outbuilding can all be listed with the main house. Unauthorised work to a listed building is a criminal offence, not a planning telling-off.

Conservation areas and World Heritage Sites. Permitted development survives here, with one condition that decides most jobs: a conservation area heat pump can't go on a wall or roof fronting a highway, and can't sit nearer to a bounding highway than the nearest part of the building. Rear and side positions only, in practice. Check for an Article 4 direction while you're at it; they're most common in conservation areas and they remove the right entirely.

Flats and maisonettes. This is where the unit count bites. Class G allows one heat pump on, or within the curtilage of, a block of flats: one for the building, not one per flat. Whoever installs first uses the right up, and every flat after that needs an application. The volume cap stays at 0.6 cubic metres too. A maisonette over a shop isn't a block of flats at all, so Class G doesn't reach it. None of that touches the freeholder's consent, which isn't planning but stops a job just as dead.

Commercial and mixed-use. Class G is a domestic right. A village hall, a surgery, an office or a farm building sits outside it, and those installations generally need an application.

Put the timeline in the quote, not in the apology later

An 8-week statutory determination applies to a householder application, 13 weeks for a major one, and the clock starts at validation rather than submission. On heritage work, add time before that for drawings and a heritage statement. Eight to thirteen weeks from the day you decide to apply is a realistic thing to tell a customer; four weeks with a shrug is not.

The fee is worth knowing so it lands in the quote rather than in a follow-up email. A householder application in England is £548 from 1 April 2026, and fees rise again on 8 December 2026, so anything slipping into next quarter should be priced on the later figure.

Where permitted development is finely balanced: a unit close to a boundary, an air-to-air system an officer may not recognise as being in scope, a lawful development certificate for proposed use costs roughly half a householder application and gives you a formal determination instead of your best reading. On a job you'd otherwise caveat, that's cheap.

What permission doesn't get you out of

An application replaces the permitted development route. It doesn't replace the acoustics.

The design obligations don't move either. Heat loss, emitter sizing, documentation, all unchanged by which planning route the job took. The council will still want noise evidence, and on a contested site an officer may want more than the MCS 020(a) sound calculation, which is written for permitted development installations rather than as a planning submission.

The practical version of all this: property status is a survey question, not a paperwork question. Spot it at the door and the timeline is a line in your quote. Spot it in week three and it's a phone call you'd rather not make.

Book a demo and see how the design and compliance evidence for a job comes together in one place.