Solar panels, heat pumps and insulation in Sandwich - Walled Town conservation area
In the Sandwich - Walled Town conservation area (Dover), 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 Dover covers this area, but the published data does not say which rights it removes — check the direction before any work. The area has 416 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. 640 homes inside the boundary have an energy certificate: 54.4% are solid-wall homes with no wall insulation, 84.7% heat with a gas boiler and 75.8% 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
640homes with an energy certificate
54.4%solid walls, no insulation
84.7%heated by a gas boiler
0heat pumps
Article 4: An Article 4 direction published by Dover covers this area, but the published data does not say which rights it removes — check the direction before any work. (Article 4(2) Direction, Town and Country Planning (General Permitted Development) Order 1995; Town and Country Planning Direction No. 1 1983, Town and Country Planning General Development Order 1977 (as amended))
What needs planning permission in Sandwich - Walled Town
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: 416 in the area (grade I: 6, II*: 25). 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: 23% 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 = 640)
Walls
Homes
Share
Solid wall (brick or stone), no insulation
348
54.4%
Cavity wall, insulated (as built or unspecified)
103
16.1%
Cavity wall, unfilled
43
6.7%
Cavity wall, filled
38
5.9%
Solid wall, insulated
29
4.5%
Timber frame
27
4.2%
Cavity wall, partly insulated
16
2.5%
Modern wall (U-value from the design)
13
2.0%
Solid wall, internal insulation
12
1.9%
Solid wall, partly insulated
6
0.9%
Other or not known
4
0.6%
Cavity wall, internal or external insulation
1
0.2%
Heating
Homes
Share
Gas boiler
542
84.7%
Electric (storage heaters, panels, boiler)
64
10.0%
Communal heating
34
5.3%
Loft / roof insulation
Homes
Share
No insulation
119
18.6%
Under 200 mm
212
33.1%
200 mm or more
162
25.3%
Insulated (depth not recorded)
72
11.2%
Flat or other home above
59
9.2%
Other
16
2.5%
Windows
Homes
Share
Double glazed
316
49.4%
Single glazed
227
35.5%
Secondary glazing
97
15.2%
CDE
Energy rating: B 2 (0.3%) · C 153 (23.9%) · D 328 (51.2%) · E 135 (21.1%) · F 15 (2.3%) · G 7 (1.1%). Houses and bungalows: 77% of the homes; solar panels on 0.5% of the certificates. Most common build period on the certificates: before 1900. Designated: 25 February 1972.
Compared with Dover and England
Share of homes
Sandwich - Walled Town
All 103 areas in Dover
England
Solid walls, no insulation
54.4%
60.8%
48.7%
Gas boiler
84.7%
77.1%
66.4%
Rated D–G
75.8%
—
56.5%
Caveats
Certificates describe a home when it was assessed; 52% of these are from 2020 or later (latest 7 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 Dover if in doubt.
Boundary: Dover District Council via planning.data.gov.uk (entity 44009744, reference {113975D9-F0CB-443F-929C-56CE895A5962}, 77.3 ha). Homes are placed by the coordinates of their UPRN (OS Open UPRN); addresses are not shown.