Solar panels, heat pumps and insulation in St John's Wood conservation area
In the St John's Wood conservation area (Westminster), 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 Westminster 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), so there these need planning permission too. The area has 297 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. 4,503 homes inside the boundary have an energy certificate: 78.2% are solid-wall homes with no wall insulation, 69.9% heat with a gas boiler and 56.2% are rated D–G; 48 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
4,503homes with an energy certificate
78.2%solid walls, no insulation
69.9%heated by a gas boiler
48heat pumps
Article 4: An Article 4 direction published by Westminster 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), so there these need planning permission too. (1-47 And 2-56 Abbey Gardens, NW8; Article 4 Basement Development Permitted Rights Removed; Article 4 Direction Class E To C3 Out Central Activity Zone)
What needs planning permission in St John's Wood
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: 297 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: 78% 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 = 4,503)
Walls
Homes
Share
Solid wall (brick or stone), no insulation
3,521
78.2%
Cavity wall, unfilled
209
4.6%
Cavity wall, insulated (as built or unspecified)
140
3.1%
Modern wall (U-value from the design)
138
3.1%
Other or not known
119
2.6%
Solid wall, internal insulation
113
2.5%
Timber frame
102
2.3%
Solid wall, insulated
48
1.1%
Cavity wall, partly insulated
36
0.8%
Cavity wall, filled
35
0.8%
Solid wall, partly insulated
28
0.6%
Solid wall, external insulation
8
0.2%
Cavity wall, internal or external insulation
6
0.1%
Heating
Homes
Share
Gas boiler
3,149
69.9%
Communal heating
911
20.2%
Electric (storage heaters, panels, boiler)
388
8.6%
Heat pump
48
1.1%
LPG
5
0.1%
Oil
2
0.0%
Loft / roof insulation
Homes
Share
No insulation
913
20.3%
Under 200 mm
264
5.9%
200 mm or more
109
2.4%
Insulated (depth not recorded)
428
9.5%
Flat or other home above
2,681
59.6%
Other
107
2.4%
Windows
Homes
Share
Double glazed
2,310
51.3%
Single glazed
1,813
40.3%
Secondary glazing
366
8.1%
Triple glazed
14
0.3%
CDE
Energy rating: B 116 (2.6%) · C 1,855 (41.2%) · D 1,846 (41.0%) · E 601 (13.3%) · F 71 (1.6%) · G 14 (0.3%). Houses and bungalows: 22% of the homes; solar panels on 0.1% of the certificates. Most common build period on the certificates: 1900-1929. Designated: 22 August 2007.
Compared with Westminster and England
Share of homes
St John's Wood
All 56 areas in Westminster
England
Solid walls, no insulation
78.2%
66.4%
48.7%
Gas boiler
69.9%
59.2%
66.4%
Rated D–G
56.2%
—
56.5%
Caveats
Certificates describe a home when it was assessed; 58% 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 Westminster if in doubt.
Boundary: City of Westminster via planning.data.gov.uk (entity 44002899, reference 08/01601/CONARA, 123.4 ha); the council's appraisal or map. Homes are placed by the coordinates of their UPRN (OS Open UPRN); addresses are not shown.