Solar panels, heat pumps and insulation in Forest Hill conservation area
In the Forest Hill conservation area (Lewisham), 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 Lewisham covers this area and removes permitted development rights for replacement windows and doors, and other alterations to the house, alterations to the roof (e.g. rooflights), painting the outside, so there these need planning permission too. The area has 15 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. 1,405 homes inside the boundary have an energy certificate: 67.9% are solid-wall homes with no wall insulation, 86.8% heat with a gas boiler and 57.2% are rated D–G; 7 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
1,405homes with an energy certificate
67.9%solid walls, no insulation
86.8%heated by a gas boiler
7heat pumps
Article 4: An Article 4 direction published by Lewisham covers this area and removes permitted development rights for replacement windows and doors, and other alterations to the house, alterations to the roof (e.g. rooflights), painting the outside, so there these need planning permission too. (Forest Hill Article 4 Direction; Forest Hill Article 4(2) Direction; Forest Hill Article 4(3) Direction; Forest Hill District Centre; Small HMO Northern Extension)
What needs planning permission in Forest Hill
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
Planning permission needed (an Article 4 direction here removes this right)
Part 1 Class A, A.3(a)
Listed buildings: 15 in the area (grade I: 0, 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: 84% 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 = 1,405)
Walls
Homes
Share
Solid wall (brick or stone), no insulation
954
67.9%
Cavity wall, insulated (as built or unspecified)
139
9.9%
Modern wall (U-value from the design)
80
5.7%
Cavity wall, unfilled
61
4.3%
Solid wall, internal insulation
38
2.7%
Timber frame
37
2.6%
Cavity wall, partly insulated
35
2.5%
Solid wall, insulated
20
1.4%
Other or not known
18
1.3%
Cavity wall, filled
17
1.2%
Cavity wall, internal or external insulation
4
0.3%
Solid wall, partly insulated
2
0.1%
Heating
Homes
Share
Gas boiler
1,219
86.8%
Electric (storage heaters, panels, boiler)
157
11.2%
Communal heating
19
1.4%
Heat pump
7
0.5%
LPG
3
0.2%
Loft / roof insulation
Homes
Share
No insulation
204
14.5%
Under 200 mm
180
12.8%
200 mm or more
96
6.8%
Insulated (depth not recorded)
134
9.5%
Flat or other home above
748
53.2%
Other
43
3.1%
Windows
Homes
Share
Double glazed
1,000
71.2%
Single glazed
344
24.5%
Secondary glazing
52
3.7%
Triple glazed
9
0.6%
CDE
Energy rating: B 86 (6.1%) · C 516 (36.7%) · D 601 (42.8%) · E 174 (12.4%) · F 22 (1.6%) · G 6 (0.4%). Houses and bungalows: 16% of the homes; solar panels on 0.2% of the certificates. Most common build period on the certificates: 1900-1929. Designated: 1 January 1976.
Compared with Lewisham and England
Share of homes
Forest Hill
All 31 areas in Lewisham
England
Solid walls, no insulation
67.9%
69.0%
48.7%
Gas boiler
86.8%
85.5%
66.4%
Rated D–G
57.2%
—
56.5%
Caveats
Certificates describe a home when it was assessed; 51% of these are from 2020 or later (latest 30 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 Lewisham if in doubt.
Boundary: London Borough of Lewisham via planning.data.gov.uk (entity 44014977, reference LEWCA13, 45.4 ha); the council's appraisal or map. Homes are placed by the coordinates of their UPRN (OS Open UPRN); addresses are not shown.