Solar panels, heat pumps and insulation in La Retraite conservation area
In the La Retraite conservation area (Lambeth), 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 Lambeth covers part of this area (about 2% of it), but the published data does not say which rights it removes — check the direction before any work. 110 homes inside the boundary have an energy certificate: 38.2% are solid-wall homes with no wall insulation, 55.5% heat with a gas boiler and 34.5% 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
110homes with an energy certificate
38.2%solid walls, no insulation
55.5%heated by a gas boiler
0heat pumps
Article 4: An Article 4 direction published by Lambeth covers part of this area (about 2% of it), but the published data does not say which rights it removes — check the direction before any work. (Modified Direction 2 - KIBAs and WNCBC)
What needs planning permission in La Retraite
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: none recorded inside the boundary; on a listed building, solar panels and heat pumps are not permitted development and need listed building consent.
Flats: 80% 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 = 110)
Walls
Homes
Share
Cavity wall, insulated (as built or unspecified)
54
49.1%
Solid wall (brick or stone), no insulation
42
38.2%
Cavity wall, filled
4
3.6%
Cavity wall, unfilled
3
2.7%
Solid wall, external insulation
2
1.8%
Solid wall, insulated
2
1.8%
Cavity wall, partly insulated
1
0.9%
Other or not known
1
0.9%
Solid wall, internal insulation
1
0.9%
Heating
Homes
Share
Gas boiler
61
55.5%
Communal heating
38
34.5%
Electric (storage heaters, panels, boiler)
10
9.1%
LPG
1
0.9%
Loft / roof insulation
Homes
Share
No insulation
9
8.2%
Under 200 mm
15
13.6%
200 mm or more
11
10.0%
Insulated (depth not recorded)
23
20.9%
Flat or other home above
52
47.3%
Windows
Homes
Share
Double glazed
67
60.9%
Single glazed
41
37.3%
Secondary glazing
2
1.8%
CD
Energy rating: B 5 (4.5%) · C 67 (60.9%) · D 30 (27.3%) · E 8 (7.3%). Houses and bungalows: 20% of the homes; solar panels on 0.9% of the certificates. Most common build period on the certificates: 1983-1990. Designated: 29 March 1982.
Compared with Lambeth and England
Share of homes
La Retraite
All 65 areas in Lambeth
England
Solid walls, no insulation
38.2%
64.5%
48.7%
Gas boiler
55.5%
73.7%
66.4%
Rated D–G
34.5%
—
56.5%
Caveats
Certificates describe a home when it was assessed; 50% of these are from 2020 or later (latest 8 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 Lambeth if in doubt.
Boundary: London Borough of Lambeth via planning.data.gov.uk (entity 44000873, reference CA36, 4.6 ha). Homes are placed by the coordinates of their UPRN (OS Open UPRN); addresses are not shown.