Solar panels, heat pumps and insulation in Thorney conservation area
In the Thorney conservation area (Peterborough), 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 Peterborough covers part of this area (about 0% of it) and removes permitted development rights for replacement windows and doors, and other alterations to the house, alterations to the roof (e.g. rooflights), painting the outside, so there these need planning permission too. The area has 40 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. 170 homes inside the boundary have an energy certificate: 64.1% are solid-wall homes with no wall insulation, 78.8% heat with a gas boiler and 76.5% 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
170homes with an energy certificate
64.1%solid walls, no insulation
78.8%heated by a gas boiler
4heat pumps
Article 4: An Article 4 direction published by Peterborough covers part of this area (about 0% of it) and removes permitted development rights for replacement windows and doors, and other alterations to the house, alterations to the roof (e.g. rooflights), painting the outside, so there these need planning permission too. (120-188 (even) Wisbech Road, Thorney; Outbuildings 120-188 (even) Wisbech Road, Thorney)
What needs planning permission in Thorney
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
Inside the Article 4 part of the area: planning permission needed; elsewhere: no permission needed (permitted development)
Part 1 Class A, A.3(a)
Listed buildings: 40 in the area (grade I: 2, II*: 2). 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: 11% 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 = 170)
Walls
Homes
Share
Solid wall (brick or stone), no insulation
109
64.1%
Cavity wall, filled
18
10.6%
Modern wall (U-value from the design)
17
10.0%
Cavity wall, insulated (as built or unspecified)
14
8.2%
Cavity wall, unfilled
8
4.7%
Cavity wall, partly insulated
1
0.6%
Other or not known
1
0.6%
Solid wall, insulated
1
0.6%
Timber frame
1
0.6%
Heating
Homes
Share
Gas boiler
134
78.8%
Electric (storage heaters, panels, boiler)
22
12.9%
Oil
6
3.5%
Heat pump
4
2.4%
Communal heating
2
1.2%
Solid fuel (wood, coal)
2
1.2%
Loft / roof insulation
Homes
Share
No insulation
22
12.9%
Under 200 mm
51
30.0%
200 mm or more
52
30.6%
Insulated (depth not recorded)
18
10.6%
Flat or other home above
10
5.9%
Other
17
10.0%
Windows
Homes
Share
Double glazed
116
68.2%
Single glazed
32
18.8%
Secondary glazing
21
12.4%
Triple glazed
1
0.6%
BCDE
Energy rating: B 17 (10.0%) · C 23 (13.5%) · D 75 (44.1%) · E 45 (26.5%) · F 8 (4.7%) · G 2 (1.2%). Houses and bungalows: 89% of the homes; solar panels on 1.2% of the certificates. Most common build period on the certificates: before 1900. Designated: 1 March 1974.
Compared with Peterborough and England
Share of homes
Thorney
All 29 areas in Peterborough
England
Solid walls, no insulation
64.1%
40.0%
48.7%
Gas boiler
78.8%
59.8%
66.4%
Rated D–G
76.5%
—
56.5%
Caveats
Certificates describe a home when it was assessed; 48% of these are from 2020 or later (latest 25 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 Peterborough if in doubt.
Boundary: Peterborough City Council via planning.data.gov.uk (entity 44004954, reference CA25, 49.3 ha); the council's appraisal or map. Homes are placed by the coordinates of their UPRN (OS Open UPRN); addresses are not shown.