Solar panels, heat pumps and insulation in Cranford Village conservation area
In the Cranford Village conservation area (Hounslow), 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 Hounslow covers part of this area (about 44% of it) but deals with other things (such as changes of use); it does not change the rules below. The area has 2 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. 405 homes inside the boundary have an energy certificate: 10.4% are solid-wall homes with no wall insulation, 86.2% heat with a gas boiler and 48.6% are rated D–G; 12 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
405homes with an energy certificate
10.4%solid walls, no insulation
86.2%heated by a gas boiler
12heat pumps
Article 4: An Article 4 direction published by Hounslow covers part of this area (about 44% of it) but deals with other things (such as changes of use); it does not change the rules below. (Dwellinghouses (C3) to small HMOs (C4) - borough-wide Article 4 Direction)
What needs planning permission in Cranford Village
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
No permission needed (permitted development)
Part 1 Class A, A.3(a)
Listed buildings: 2 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: 34% 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 = 405)
Walls
Homes
Share
Cavity wall, filled
118
29.1%
Cavity wall, unfilled
113
27.9%
Cavity wall, insulated (as built or unspecified)
58
14.3%
Modern wall (U-value from the design)
48
11.9%
Solid wall (brick or stone), no insulation
42
10.4%
Cavity wall, partly insulated
11
2.7%
Timber frame
6
1.5%
Cavity wall, internal or external insulation
3
0.7%
Solid wall, internal insulation
2
0.5%
Other or not known
1
0.2%
Solid wall, external insulation
1
0.2%
Solid wall, insulated
1
0.2%
Solid wall, partly insulated
1
0.2%
Heating
Homes
Share
Gas boiler
349
86.2%
Electric (storage heaters, panels, boiler)
41
10.1%
Heat pump
12
3.0%
Communal heating
2
0.5%
LPG
1
0.2%
Loft / roof insulation
Homes
Share
No insulation
57
14.1%
Under 200 mm
104
25.7%
200 mm or more
61
15.1%
Insulated (depth not recorded)
78
19.3%
Flat or other home above
73
18.0%
Other
32
7.9%
Windows
Homes
Share
Double glazed
380
93.8%
Secondary glazing
14
3.5%
Single glazed
7
1.7%
Triple glazed
4
1.0%
BCDE
Energy rating: B 38 (9.4%) · C 170 (42.0%) · D 154 (38.0%) · E 36 (8.9%) · F 5 (1.2%) · G 2 (0.5%). Houses and bungalows: 66% of the homes; solar panels on 0.0% of the certificates. Most common build period on the certificates: 1930-1949. Designated: 25 June 1991.
Compared with Hounslow and England
Share of homes
Cranford Village
All 29 areas in Hounslow
England
Solid walls, no insulation
10.4%
49.9%
48.7%
Gas boiler
86.2%
77.4%
66.4%
Rated D–G
48.6%
—
56.5%
Caveats
Certificates describe a home when it was assessed; 54% of these are from 2020 or later (latest 17 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 Hounslow if in doubt.
Boundary: London Borough of Hounslow via planning.data.gov.uk (entity 44015582, reference HSLCA16, 47.3 ha); the council's appraisal or map. Homes are placed by the coordinates of their UPRN (OS Open UPRN); addresses are not shown.