Solar panels, heat pumps and insulation in Piddle Valley conservation area
In the Piddle Valley 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, but the published data does not say which rights it removes — check the direction before any work. The area has 78 listed buildings; on a listed building solar panels and heat pumps are not permitted development at all and need planning permission and listed building consent. 82 homes inside the boundary have an energy certificate: 30% are solid-wall homes with no wall insulation, 0% heat with a gas boiler and 94% are rated D–G; 5 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
82homes with an energy certificate
30%solid walls, no insulation
0%heated by a gas boiler
5heat pumps
Article 4: An Article 4 direction published by Dorset covers this area, but the published data does not say which rights it removes — check the direction before any work. (Land at Bladen Valley, Briantspuddle; Piddle Valley Conservation Area; Piddle Valley No2)
What needs planning permission in Piddle Valley
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), unless an Article 4 direction removes it — check with the council
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), unless an Article 4 direction removes it — check with the council
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)
Prior approval of appearance from the council, unless an Article 4 direction removes it — check with the council
Replacement windows and doors of similar appearance
No permission needed (permitted development), unless an Article 4 direction removes it — check with the council
Part 1 Class A, A.3(a)
Listed buildings: 78 in the area (grade I: 1, II*: 1). The table is for houses that are not listed: on a listed building, solar panels and air source heat pumps are not permitted development at all (they need planning permission), and any of these works needs listed building consent.
Flats: 5% 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 = 82)
Walls
Homes
Share
Cavity wall, unfilled
27
33%
Solid wall (brick or stone), no insulation
25
30%
Cavity wall, filled
18
22%
Cavity wall, insulated (as built or unspecified)
6
7%
Solid wall, insulated
2
2%
Cavity wall, internal or external insulation
1
1%
Cavity wall, partly insulated
1
1%
Modern wall (U-value from the design)
1
1%
Timber frame
1
1%
Heating
Homes
Share
Oil
42
51%
Electric (storage heaters, panels, boiler)
21
26%
Communal heating
6
7%
Heat pump
5
6%
LPG
4
5%
Solid fuel (wood, coal)
4
5%
Loft / roof insulation
Homes
Share
No insulation
9
11%
Under 200 mm
11
13%
200 mm or more
28
34%
Insulated (depth not recorded)
13
16%
Flat or other home above
2
2%
Other
19
23%
Windows
Homes
Share
Double glazed
53
65%
Single glazed
15
18%
Secondary glazing
14
17%
DEF
Energy rating: B 2 (2%) · C 3 (4%) · D 26 (32%) · E 33 (40%) · F 13 (16%) · G 5 (6%). Houses and bungalows: 95% of the homes; solar panels on 6% of the certificates. Most common build period on the certificates: 1950-1966. Designated: 30 March 1977.
Compared with Dorset and England
Share of homes
Piddle Valley
All 311 areas in Dorset
England
Solid walls, no insulation
30%
37.3%
48.7%
Gas boiler
0%
60.1%
66.4%
Rated D–G
94%
—
56.5%
Caveats
Certificates describe a home when it was assessed; 29% of these are from 2020 or later (latest 22 September 2026). “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 44013936, reference PIDD, 263.0 ha). Homes are placed by the coordinates of their UPRN (OS Open UPRN); addresses are not shown.