Solar panels, heat pumps and insulation in Telegraph Hill conservation area
In the Telegraph 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 6 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. 2,144 homes inside the boundary have an energy certificate: 83.8% are solid-wall homes with no wall insulation, 91.7% heat with a gas boiler and 59.5% are rated D–G; 8 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
2,144homes with an energy certificate
83.8%solid walls, no insulation
91.7%heated by a gas boiler
8heat 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. (Small HMO Northern Extension; Telegraph Hill)
What needs planning permission in Telegraph 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: 6 in the area. 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: 73% 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 = 2,144)
Walls
Homes
Share
Solid wall (brick or stone), no insulation
1,796
83.8%
Cavity wall, insulated (as built or unspecified)
70
3.3%
Cavity wall, filled
69
3.2%
Solid wall, internal insulation
40
1.9%
Cavity wall, unfilled
39
1.8%
Modern wall (U-value from the design)
37
1.7%
Timber frame
34
1.6%
Other or not known
32
1.5%
Solid wall, insulated
10
0.5%
Cavity wall, partly insulated
9
0.4%
Solid wall, partly insulated
4
0.2%
Cavity wall, internal or external insulation
3
0.1%
Solid wall, external insulation
1
0.0%
Heating
Homes
Share
Gas boiler
1,967
91.7%
Electric (storage heaters, panels, boiler)
136
6.3%
Communal heating
31
1.4%
Heat pump
8
0.4%
LPG
1
0.0%
Other
1
0.0%
Loft / roof insulation
Homes
Share
No insulation
291
13.6%
Under 200 mm
369
17.2%
200 mm or more
315
14.7%
Insulated (depth not recorded)
120
5.6%
Flat or other home above
1,022
47.7%
Other
27
1.3%
Windows
Homes
Share
Double glazed
1,510
70.4%
Single glazed
581
27.1%
Secondary glazing
49
2.3%
Triple glazed
4
0.2%
CDE
Energy rating: B 46 (2.1%) · C 822 (38.3%) · D 981 (45.8%) · E 242 (11.3%) · F 34 (1.6%) · G 19 (0.9%). Houses and bungalows: 27% of the homes; solar panels on 0.4% of the certificates. Most common build period on the certificates: 1900-1929. Designated: 1 January 1990.
Compared with Lewisham and England
Share of homes
Telegraph Hill
All 31 areas in Lewisham
England
Solid walls, no insulation
83.8%
69.0%
48.7%
Gas boiler
91.7%
85.5%
66.4%
Rated D–G
59.5%
—
56.5%
Caveats
Certificates describe a home when it was assessed; 57% of these are from 2020 or later (latest 29 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 44014984, reference LEWCA20, 76.7 ha); the council's appraisal or map. Homes are placed by the coordinates of their UPRN (OS Open UPRN); addresses are not shown.