Solar panels, heat pumps and insulation in Redruth conservation area
In the Redruth conservation area (Cornwall), 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 51 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. 640 homes inside the boundary have an energy certificate: 52.2% are solid-wall homes with no wall insulation, 54.7% heat with a gas boiler and 62.2% are rated D–G; 2 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
640homes with an energy certificate
52.2%solid walls, no insulation
54.7%heated by a gas boiler
2heat pumps
Article 4: Cornwall does not publish Article 4 areas on planning.data.gov.uk — check with the council.
What needs planning permission in Redruth
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: 51 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: 57% 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 = 640)
Walls
Homes
Share
Solid wall (brick or stone), no insulation
334
52.2%
Timber frame
63
9.8%
Solid wall, insulated
61
9.5%
Modern wall (U-value from the design)
59
9.2%
Solid wall, internal insulation
46
7.2%
Cavity wall, insulated (as built or unspecified)
44
6.9%
Cavity wall, unfilled
16
2.5%
Cavity wall, filled
6
0.9%
Cavity wall, partly insulated
5
0.8%
Cavity wall, internal or external insulation
3
0.5%
Solid wall, partly insulated
2
0.3%
Solid wall, external insulation
1
0.2%
Heating
Homes
Share
Gas boiler
350
54.7%
Electric (storage heaters, panels, boiler)
262
40.9%
Communal heating
22
3.4%
Oil
3
0.5%
Heat pump
2
0.3%
Solid fuel (wood, coal)
1
0.2%
Loft / roof insulation
Homes
Share
No insulation
55
8.6%
Under 200 mm
106
16.6%
200 mm or more
193
30.2%
Insulated (depth not recorded)
63
9.8%
Flat or other home above
182
28.4%
Other
41
6.4%
Windows
Homes
Share
Double glazed
519
81.1%
Single glazed
101
15.8%
Secondary glazing
19
3.0%
Triple glazed
1
0.2%
CDE
Energy rating: A 1 (0.2%) · B 33 (5.2%) · C 208 (32.5%) · D 218 (34.1%) · E 128 (20.0%) · F 32 (5.0%) · G 20 (3.1%). Houses and bungalows: 43% of the homes; solar panels on 0.2% of the certificates. Most common build period on the certificates: before 1900. Designated: 27 April 1983.
Compared with Cornwall and England
Share of homes
Redruth
All 145 areas in Cornwall
England
Solid walls, no insulation
52.2%
56.0%
48.7%
Gas boiler
54.7%
51.3%
66.4%
Rated D–G
62.2%
—
56.5%
Caveats
Certificates describe a home when it was assessed; 53% of these are from 2020 or later (latest 30 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 Cornwall if in doubt.
Boundary: Cornwall Council via planning.data.gov.uk (entity 44003997, reference DCO166, 28.2 ha); the council's appraisal or map. Homes are placed by the coordinates of their UPRN (OS Open UPRN); addresses are not shown.