Permitted Development

Planning rules allowing certain works (including most ASHP and solar installations) without a full planning application, subject to size and siting limits.

Permitted Development (PD) rights, set out in the Town and Country Planning (General Permitted Development) Order 2015 (as amended), allow most domestic renewable installs without a full planning application. From May 2025, the ASHP PD limits were extended:

1 unit per dwelling (no longer just one heat pump and one AC unit limit)
1.5m³ enclosure volume max
1m from boundary minimum
Not on principal elevation if facing a highway

Solar PV PD allows up to 1m projection above roof slope, total area not specified for domestic, and no protrusion above the ridge.

PD does not apply in conservation areas, AONBs (large parts of Cornwall), Article 4 areas, or to listed buildings. Most of central Cornwall and the AONB coast falls into one of these. CCS surveys planning constraints as part of every quote. See our heat pump page.