Solar panels, heat pumps and insulation in Dorchester 6 conservation area
In the Dorchester 6 conservation area (Dorset), external wall insulation needs planning permission, and so does an air source heat pump on a wall or roof facing the road; one at the back or side, internal and loft insulation and solar panels on a roof slope normally do not. An Article 4 direction published by Dorset covers this area and removes permitted development rights for painting the outside, so there these need planning permission too. 52 homes inside the boundary have an energy certificate: 44% are solid-wall homes with no wall insulation, 94% heat with a gas boiler and 92% are rated D–G; 0 have a heat pump. EPC register November 2026; rules as at 21 October 2026.
Data: EPC register November 2026 (latest certificate per home), conservation area boundaries 3 November 2026, permitted development rules as at 21 October 2026 · calculated 5 November 2026 · Methodology and sources
52homes with an energy certificate
44%solid walls, no insulation
94%heated by a gas boiler
0heat pumps
Article 4: An Article 4 direction published by Dorset covers this area and removes permitted development rights for painting the outside, so there these need planning permission too. (Dorchester Conservation Area)
What needs planning permission in Dorchester 6
Work (house, not listed)
In a conservation area
Rule
Air source heat pump on a wall or roof facing the road, or nearer the road than the house
Planning permission needed
Part 14 Class G, G.1(j)
Air source heat pump at the back or side (outdoor unit up to 1.5 m³, MCS Planning Standards, one per house — two on a detached house)
No permission needed (permitted development)
Part 14 Class G
Solar panels on a pitched roof (up to 0.2 m proud, not above the ridge)
No permission needed (permitted development)
Part 14 Class A, A.2(c)
Solar panels on a wall, balcony or roof enclosure facing the road
Planning permission needed
Part 14 Class A, A.2(e)
Solar panels on a flat roof (up to 0.6 m above the roof)
Replacement windows and doors of similar appearance
No permission needed (permitted development)
Part 1 Class A, A.3(a)
Listed buildings: none recorded inside the boundary; on a listed building, solar panels and heat pumps are not permitted development and need listed building consent.
Flats: 8% of the certified homes here are flats or maisonettes. Homes in a block of flats have no householder rights for alterations; heat pumps and solar have their own, tighter rules for blocks of flats.
The homes in the area (latest certificate per home, n = 52)
Walls
Homes
Share
Solid wall (brick or stone), no insulation
23
44%
Cavity wall, unfilled
22
42%
Cavity wall, filled
6
12%
Cavity wall, internal or external insulation
1
2%
Heating
Homes
Share
Gas boiler
49
94%
Electric (storage heaters, panels, boiler)
2
4%
Oil
1
2%
Loft / roof insulation
Homes
Share
No insulation
14
27%
Under 200 mm
20
38%
200 mm or more
15
29%
Insulated (depth not recorded)
2
4%
Flat or other home above
1
2%
Windows
Homes
Share
Double glazed
46
88%
Single glazed
5
10%
Secondary glazing
1
2%
DE
Energy rating: B 1 (2%) · C 3 (6%) · D 29 (56%) · E 16 (31%) · F 3 (6%). Houses and bungalows: 92% of the homes; solar panels on 0% of the certificates. Most common build period on the certificates: 1900-1929. Designated: 4 January 1990.
Compared with Dorset and England
Share of homes
Dorchester 6
All 311 areas in Dorset
England
Solid walls, no insulation
44%
37.3%
48.7%
Gas boiler
94%
60.1%
66.4%
Rated D–G
92%
—
56.5%
Caveats
Certificates describe a home when it was assessed; 38% of these are from 2020 or later (latest 22 August 2025). “No insulation (assumed)” is the assessor's default for older walls.
The rules are England's national permitted development rules (General Permitted Development Order 2015, Schedule 2, as at 21 October 2026). They do not cover building regulations or a council's own conditions. This is not a planning decision: ask Dorset if in doubt.
Boundary: Dorset Council via planning.data.gov.uk (entity 44013819, reference DORC6, 2.2 ha). Homes are placed by the coordinates of their UPRN (OS Open UPRN); addresses are not shown.