Solar panels, heat pumps and insulation in Crabtree conservation area
In the Crabtree conservation area (Hammersmith & Fulham), 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. The area has 3 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. 1,983 homes inside the boundary have an energy certificate: 85.2% are solid-wall homes with no wall insulation, 89.2% heat with a gas boiler and 57.7% are rated D–G; 6 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
1,983homes with an energy certificate
85.2%solid walls, no insulation
89.2%heated by a gas boiler
6heat pumps
Article 4: Hammersmith & Fulham does not publish Article 4 areas on planning.data.gov.uk — check with the council.
What needs planning permission in Crabtree
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: 3 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: 65% 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 = 1,983)
Walls
Homes
Share
Solid wall (brick or stone), no insulation
1,690
85.2%
Modern wall (U-value from the design)
89
4.5%
Cavity wall, insulated (as built or unspecified)
46
2.3%
Solid wall, internal insulation
42
2.1%
Cavity wall, unfilled
33
1.7%
Solid wall, insulated
24
1.2%
Other or not known
23
1.2%
Cavity wall, partly insulated
18
0.9%
Timber frame
13
0.7%
Solid wall, partly insulated
3
0.2%
Cavity wall, filled
2
0.1%
Heating
Homes
Share
Gas boiler
1,769
89.2%
Communal heating
126
6.4%
Electric (storage heaters, panels, boiler)
79
4.0%
Heat pump
6
0.3%
LPG
2
0.1%
Solid fuel (wood, coal)
1
0.1%
Loft / roof insulation
Homes
Share
No insulation
562
28.3%
Under 200 mm
191
9.6%
200 mm or more
64
3.2%
Insulated (depth not recorded)
357
18.0%
Flat or other home above
745
37.6%
Other
64
3.2%
Windows
Homes
Share
Double glazed
1,695
85.6%
Single glazed
241
12.2%
Secondary glazing
41
2.1%
Triple glazed
4
0.2%
CDE
Energy rating: A 1 (0.1%) · B 108 (5.4%) · C 729 (36.8%) · D 922 (46.5%) · E 189 (9.5%) · F 21 (1.1%) · G 13 (0.7%). Houses and bungalows: 35% of the homes; solar panels on 0.3% of the certificates. Most common build period on the certificates: 1900-1929.
Compared with Hammersmith & Fulham and England
Share of homes
Crabtree
All 46 areas in Hammersmith & Fulham
England
Solid walls, no insulation
85.2%
65.3%
48.7%
Gas boiler
89.2%
70.7%
66.4%
Rated D–G
57.7%
—
56.5%
Caveats
Certificates describe a home when it was assessed; 50% of these are from 2020 or later (latest 28 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 Hammersmith & Fulham if in doubt.
Boundary: London Borough of Hammersmith & Fulham via planning.data.gov.uk (entity 44008378, reference 28, 51.5 ha). Homes are placed by the coordinates of their UPRN (OS Open UPRN); addresses are not shown.