Solar panels, heat pumps and insulation in Warminster conservation area
In the Warminster conservation area (Wiltshire), 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. The area has 171 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. 882 homes inside the boundary have an energy certificate: 49.3% are solid-wall homes with no wall insulation, 60.5% heat with a gas boiler and 55.4% are rated D–G; 6 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
882homes with an energy certificate
49.3%solid walls, no insulation
60.5%heated by a gas boiler
6heat pumps
Article 4: Wiltshire publishes its Article 4 areas on planning.data.gov.uk and none overlaps this area; a direction can still exist on paper, so check with the council.
What needs planning permission in Warminster
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: 171 in the area (grade I: 1, II*: 10). 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: 45% 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 = 882)
Walls
Homes
Share
Solid wall (brick or stone), no insulation
435
49.3%
Cavity wall, insulated (as built or unspecified)
167
18.9%
Modern wall (U-value from the design)
131
14.9%
Cavity wall, filled
51
5.8%
Timber frame
25
2.8%
Solid wall, insulated
18
2.0%
Solid wall, internal insulation
18
2.0%
Cavity wall, partly insulated
17
1.9%
Cavity wall, unfilled
16
1.8%
Other or not known
2
0.2%
Cavity wall, internal or external insulation
1
0.1%
Solid wall, partly insulated
1
0.1%
Heating
Homes
Share
Gas boiler
534
60.5%
Electric (storage heaters, panels, boiler)
336
38.1%
Heat pump
6
0.7%
Communal heating
3
0.3%
Solid fuel (wood, coal)
2
0.2%
Oil
1
0.1%
Loft / roof insulation
Homes
Share
No insulation
97
11.0%
Under 200 mm
213
24.1%
200 mm or more
182
20.6%
Insulated (depth not recorded)
114
12.9%
Flat or other home above
192
21.8%
Other
84
9.5%
Windows
Homes
Share
Double glazed
729
82.7%
Single glazed
107
12.1%
Secondary glazing
45
5.1%
Triple glazed
1
0.1%
BCDE
Energy rating: A 1 (0.1%) · B 101 (11.5%) · C 291 (33.0%) · D 285 (32.3%) · E 168 (19.0%) · F 30 (3.4%) · G 6 (0.7%). Houses and bungalows: 55% of the homes; solar panels on 0.1% of the certificates. Most common build period on the certificates: before 1900. Designated: 1 January 1973.
Compared with Wiltshire and England
Share of homes
Warminster
All 244 areas in Wiltshire
England
Solid walls, no insulation
49.3%
42.5%
48.7%
Gas boiler
60.5%
45.5%
66.4%
Rated D–G
55.4%
—
56.5%
Caveats
Certificates describe a home when it was assessed; 60% of these are from 2020 or later (latest 14 October 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 Wiltshire if in doubt.
Boundary: Wiltshire Council via planning.data.gov.uk (entity 44015300, reference CA/W/212, 44.8 ha); the council's appraisal or map. Homes are placed by the coordinates of their UPRN (OS Open UPRN); addresses are not shown.