Solar panels, heat pumps and insulation in Thurloe/Smith's Charity conservation area
In the Thurloe/Smith's Charity conservation area (Kensington and Chelsea), 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 Kensington and Chelsea covers this area and removes permitted development rights for replacement windows and doors, and other alterations to the house, so there these need planning permission too. The area has 116 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. 2,779 homes inside the boundary have an energy certificate: 83.7% are solid-wall homes with no wall insulation, 70.3% heat with a gas boiler and 61.3% are rated D–G; 22 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
2,779homes with an energy certificate
83.7%solid walls, no insulation
70.3%heated by a gas boiler
22heat pumps
Article 4: An Article 4 direction published by Kensington and Chelsea covers this area and removes permitted development rights for replacement windows and doors, and other alterations to the house, so there these need planning permission too. (Article 4 - No 100; Article 4 - No 106; Article 4 - No 63; Article 4 - No 79)
What needs planning permission in Thurloe/Smith's Charity
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: 116 in the area (grade I: 0, II*: 6). 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: 79% 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 = 2,779)
Walls
Homes
Share
Solid wall (brick or stone), no insulation
2,325
83.7%
Timber frame
144
5.2%
Cavity wall, insulated (as built or unspecified)
64
2.3%
Solid wall, internal insulation
54
1.9%
Modern wall (U-value from the design)
53
1.9%
Solid wall, insulated
38
1.4%
Other or not known
31
1.1%
Cavity wall, unfilled
30
1.1%
Solid wall, partly insulated
24
0.9%
Cavity wall, partly insulated
11
0.4%
Cavity wall, internal or external insulation
3
0.1%
Cavity wall, filled
1
0.0%
Solid wall, external insulation
1
0.0%
Heating
Homes
Share
Gas boiler
1,955
70.3%
Communal heating
400
14.4%
Electric (storage heaters, panels, boiler)
398
14.3%
Heat pump
22
0.8%
LPG
4
0.1%
Loft / roof insulation
Homes
Share
No insulation
563
20.3%
Under 200 mm
161
5.8%
200 mm or more
60
2.2%
Insulated (depth not recorded)
284
10.2%
Flat or other home above
1,652
59.4%
Other
59
2.1%
Windows
Homes
Share
Single glazed
1,283
46.2%
Double glazed
1,075
38.7%
Secondary glazing
412
14.8%
Triple glazed
9
0.3%
CDE
Energy rating: A 1 (0.0%) · B 35 (1.3%) · C 1,039 (37.4%) · D 1,160 (41.7%) · E 461 (16.6%) · F 65 (2.3%) · G 18 (0.6%). Houses and bungalows: 21% of the homes; solar panels on 0.1% of the certificates. Most common build period on the certificates: before 1900. Designated: 1 January 1968.
Compared with Kensington and Chelsea and England
Share of homes
Thurloe/Smith's Charity
All 44 areas in Kensington and Chelsea
England
Solid walls, no insulation
83.7%
79.7%
48.7%
Gas boiler
70.3%
72.9%
66.4%
Rated D–G
61.3%
—
56.5%
Caveats
Certificates describe a home when it was assessed; 52% 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 Kensington and Chelsea if in doubt.
Boundary: Royal Borough of Kensington and Chelsea via planning.data.gov.uk (entity 44012777, reference 19, 47.4 ha); the council's appraisal or map. Homes are placed by the coordinates of their UPRN (OS Open UPRN); addresses are not shown.