Solar panels, heat pumps and insulation in St. David's conservation area
In the St. David's conservation area (Exeter), 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 Exeter covers this area but deals with other things (such as changes of use); it does not change the rules below. The area has 97 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. 1,053 homes inside the boundary have an energy certificate: 38.6% are solid-wall homes with no wall insulation, 63.2% heat with a gas boiler and 48.8% are rated D–G; 15 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
1,053homes with an energy certificate
38.6%solid walls, no insulation
63.2%heated by a gas boiler
15heat pumps
Article 4: An Article 4 direction published by Exeter covers this area but deals with other things (such as changes of use); it does not change the rules below. (2023 Article 4 Direction)
What needs planning permission in St. David's
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: 97 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: 70% 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 = 1,053)
Walls
Homes
Share
Solid wall (brick or stone), no insulation
406
38.6%
Cavity wall, insulated (as built or unspecified)
211
20.0%
Cavity wall, unfilled
97
9.2%
Timber frame
82
7.8%
Solid wall, insulated
70
6.6%
Cavity wall, filled
60
5.7%
Solid wall, internal insulation
59
5.6%
Modern wall (U-value from the design)
48
4.6%
Cavity wall, partly insulated
9
0.9%
Cavity wall, internal or external insulation
4
0.4%
Solid wall, partly insulated
4
0.4%
Solid wall, external insulation
2
0.2%
Other or not known
1
0.1%
Heating
Homes
Share
Gas boiler
665
63.2%
Electric (storage heaters, panels, boiler)
350
33.2%
Communal heating
23
2.2%
Heat pump
15
1.4%
Loft / roof insulation
Homes
Share
No insulation
116
11.0%
Under 200 mm
106
10.1%
200 mm or more
177
16.8%
Insulated (depth not recorded)
164
15.6%
Flat or other home above
462
43.9%
Other
28
2.7%
Windows
Homes
Share
Double glazed
767
72.8%
Single glazed
243
23.1%
Secondary glazing
38
3.6%
Triple glazed
5
0.5%
BCDE
Energy rating: B 87 (8.3%) · C 452 (42.9%) · D 329 (31.2%) · E 154 (14.6%) · F 25 (2.4%) · G 6 (0.6%). Houses and bungalows: 30% of the homes; solar panels on 0.4% of the certificates. Most common build period on the certificates: before 1900. Designated: 22 March 1993.
Compared with Exeter and England
Share of homes
St. David's
All 20 areas in Exeter
England
Solid walls, no insulation
38.6%
35.2%
48.7%
Gas boiler
63.2%
69.4%
66.4%
Rated D–G
48.8%
—
56.5%
Caveats
Certificates describe a home when it was assessed; 61% 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 Exeter if in doubt.
Boundary: Exeter City Council via planning.data.gov.uk (entity 44015005, reference CA18, 39.4 ha); the council's appraisal or map. Homes are placed by the coordinates of their UPRN (OS Open UPRN); addresses are not shown.