Solar panels, heat pumps and insulation in Wimbledon West conservation area
In the Wimbledon West conservation area (Merton), 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 49 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. 1,800 homes inside the boundary have an energy certificate: 47.4% are solid-wall homes with no wall insulation, 85.3% heat with a gas boiler and 57.5% are rated D–G; 33 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
1,800homes with an energy certificate
47.4%solid walls, no insulation
85.3%heated by a gas boiler
33heat pumps
Article 4: Merton does not publish Article 4 areas on planning.data.gov.uk — check with the council.
What needs planning permission in Wimbledon West
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: 49 in the area (grade I: 0, II*: 2). 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: 59% 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 = 1,800)
Walls
Homes
Share
Solid wall (brick or stone), no insulation
854
47.4%
Cavity wall, insulated (as built or unspecified)
249
13.8%
Cavity wall, unfilled
244
13.6%
Cavity wall, filled
127
7.1%
Modern wall (U-value from the design)
111
6.2%
Cavity wall, partly insulated
76
4.2%
Timber frame
65
3.6%
Solid wall, internal insulation
31
1.7%
Other or not known
18
1.0%
Solid wall, insulated
14
0.8%
Solid wall, partly insulated
6
0.3%
Solid wall, external insulation
4
0.2%
Cavity wall, internal or external insulation
1
0.1%
Heating
Homes
Share
Gas boiler
1,535
85.3%
Electric (storage heaters, panels, boiler)
141
7.8%
Communal heating
89
4.9%
Heat pump
33
1.8%
LPG
1
0.1%
Oil
1
0.1%
Loft / roof insulation
Homes
Share
No insulation
246
13.7%
Under 200 mm
300
16.7%
200 mm or more
130
7.2%
Insulated (depth not recorded)
313
17.4%
Flat or other home above
710
39.4%
Other
101
5.6%
Windows
Homes
Share
Double glazed
1,500
83.3%
Single glazed
268
14.9%
Secondary glazing
29
1.6%
Triple glazed
3
0.2%
CDE
Energy rating: A 6 (0.3%) · B 112 (6.2%) · C 647 (35.9%) · D 672 (37.3%) · E 298 (16.6%) · F 58 (3.2%) · G 7 (0.4%). Houses and bungalows: 41% of the homes; solar panels on 0.3% of the certificates. Most common build period on the certificates: 1900-1929. Designated: 1 January 1968.
Compared with Merton and England
Share of homes
Wimbledon West
All 28 areas in Merton
England
Solid walls, no insulation
47.4%
52.5%
48.7%
Gas boiler
85.3%
85.4%
66.4%
Rated D–G
57.5%
—
56.5%
Caveats
Certificates describe a home when it was assessed; 50% of these are from 2020 or later (latest 15 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 Merton if in doubt.
Boundary: London Borough of Merton via planning.data.gov.uk (entity 44005413, reference 2831, 114.7 ha); the council's appraisal or map. Homes are placed by the coordinates of their UPRN (OS Open UPRN); addresses are not shown.