Solar panels, heat pumps and insulation in South Warnborough conservation area
In the South Warnborough conservation area (Hart), 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 Hart covers this area, but the published data does not say which rights it removes — check the direction before any work. The area has 22 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. 62 homes inside the boundary have an energy certificate: 27% are solid-wall homes with no wall insulation, 87% heat with a gas boiler and 63% are rated D–G; 4 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
62homes with an energy certificate
27%solid walls, no insulation
87%heated by a gas boiler
4heat pumps
Article 4: An Article 4 direction published by Hart covers this area, but the published data does not say which rights it removes — check the direction before any work. (South Warnborough)
What needs planning permission in South Warnborough
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: 22 in the area (grade I: 0, II*: 1). 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: 3% 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 = 62)
Walls
Homes
Share
Solid wall (brick or stone), no insulation
17
27%
Cavity wall, insulated (as built or unspecified)
14
23%
Modern wall (U-value from the design)
8
13%
Cavity wall, unfilled
7
11%
Timber frame
6
10%
Cavity wall, partly insulated
4
6%
Solid wall, insulated
3
5%
Cavity wall, filled
2
3%
Cavity wall, internal or external insulation
1
2%
Heating
Homes
Share
Gas boiler
54
87%
Heat pump
4
6%
Oil
4
6%
Loft / roof insulation
Homes
Share
No insulation
9
15%
Under 200 mm
10
16%
200 mm or more
16
26%
Insulated (depth not recorded)
17
27%
Flat or other home above
1
2%
Other
9
15%
Windows
Homes
Share
Double glazed
50
81%
Single glazed
7
11%
Secondary glazing
5
8%
BCDEF
Energy rating: A 1 (2%) · B 5 (8%) · C 17 (27%) · D 23 (37%) · E 10 (16%) · F 6 (10%). Houses and bungalows: 97% of the homes; solar panels on 5% of the certificates. Most common build period on the certificates: before 1900. Designated: 16 December 1999.
Compared with Hart and England
Share of homes
South Warnborough
All 39 areas in Hart
England
Solid walls, no insulation
27%
25.9%
48.7%
Gas boiler
87%
80.4%
66.4%
Rated D–G
63%
—
56.5%
Caveats
Certificates describe a home when it was assessed; 50% of these are from 2020 or later (latest 20 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 Hart if in doubt.
Boundary: Hart District Council via planning.data.gov.uk (entity 44016506, reference 35-1, 35.1 ha); the council's appraisal or map. Homes are placed by the coordinates of their UPRN (OS Open UPRN); addresses are not shown.