Solar panels, heat pumps and insulation in Brookmill Road conservation area
In the Brookmill Road 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. 375 homes inside the boundary have an energy certificate: 92.8% are solid-wall homes with no wall insulation, 98.9% heat with a gas boiler and 70.1% are rated D–G; 2 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
375homes with an energy certificate
92.8%solid walls, no insulation
98.9%heated by a gas boiler
2heat 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. (Brookmill Road Conservation Area/ Article 4 Direction; Small HMO Northern Extension)
What needs planning permission in Brookmill Road
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: none recorded inside the boundary; on a listed building, solar panels and heat pumps are not permitted development and need listed building consent.
Flats: 33% 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 = 375)
Walls
Homes
Share
Solid wall (brick or stone), no insulation
348
92.8%
Cavity wall, unfilled
10
2.7%
Solid wall, insulated
4
1.1%
Cavity wall, insulated (as built or unspecified)
3
0.8%
Modern wall (U-value from the design)
3
0.8%
Cavity wall, partly insulated
2
0.5%
Solid wall, internal insulation
2
0.5%
Cavity wall, filled
1
0.3%
Solid wall, partly insulated
1
0.3%
Timber frame
1
0.3%
Heating
Homes
Share
Gas boiler
371
98.9%
Heat pump
2
0.5%
Communal heating
1
0.3%
Electric (storage heaters, panels, boiler)
1
0.3%
Loft / roof insulation
Homes
Share
No insulation
56
14.9%
Under 200 mm
82
21.9%
200 mm or more
154
41.1%
Insulated (depth not recorded)
16
4.3%
Flat or other home above
64
17.1%
Other
3
0.8%
Windows
Homes
Share
Double glazed
282
75.2%
Single glazed
92
24.5%
Secondary glazing
1
0.3%
CDE
Energy rating: B 4 (1.1%) · C 108 (28.8%) · D 222 (59.2%) · E 38 (10.1%) · F 3 (0.8%). Houses and bungalows: 67% of the homes; solar panels on 0.0% of the certificates. Most common build period on the certificates: 1900-1929. Designated: 1 January 1972.
Compared with Lewisham and England
Share of homes
Brookmill Road
All 31 areas in Lewisham
England
Solid walls, no insulation
92.8%
69.0%
48.7%
Gas boiler
98.9%
85.5%
66.4%
Rated D–G
70.1%
—
56.5%
Caveats
Certificates describe a home when it was assessed; 70% of these are from 2020 or later (latest 27 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 44014966, reference LEWCA2, 10.1 ha); the council's appraisal or map. Homes are placed by the coordinates of their UPRN (OS Open UPRN); addresses are not shown.