Solar panels, heat pumps and insulation in St Albans - Old Gasworks and the Abbey Line conservation area
In the St Albans - Old Gasworks and the Abbey Line conservation area (St Albans), 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 St Albans 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. 33 homes inside the boundary have an energy certificate: 0% are solid-wall homes with no wall insulation, 76% heat with a gas boiler and 9% are rated D–G; 0 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
33homes with an energy certificate
0%solid walls, no insulation
76%heated by a gas boiler
0heat pumps
Article 4: An Article 4 direction published by St Albans 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. (St Albans Abbey Station)
What needs planning permission in St Albans - Old Gasworks and the Abbey Line
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: none recorded inside the boundary; on a listed building, solar panels and heat pumps are not permitted development and need listed building consent.
Flats: 100% 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 = 33)
Walls
Homes
Share
Modern wall (U-value from the design)
26
79%
Cavity wall, insulated (as built or unspecified)
5
15%
Cavity wall, filled
1
3%
Timber frame
1
3%
Heating
Homes
Share
Gas boiler
25
76%
Electric (storage heaters, panels, boiler)
8
24%
Loft / roof insulation
Homes
Share
Insulated (depth not recorded)
1
3%
Flat or other home above
22
67%
Other
10
30%
Windows
Homes
Share
Double glazed
33
100%
B
Energy rating: B 28 (85%) · C 2 (6%) · D 2 (6%) · E 1 (3%). Houses and bungalows: 0% of the homes; solar panels on 0% of the certificates. Most common build period on the certificates: 2020. Designated: 24 March 1969.
Compared with St Albans and England
Share of homes
St Albans - Old Gasworks and the Abbey Line
All 45 areas in St Albans
England
Solid walls, no insulation
0%
37.1%
48.7%
Gas boiler
76%
76.8%
66.4%
Rated D–G
9%
—
56.5%
Caveats
Certificates describe a home when it was assessed; 97% of these are from 2020 or later (latest 29 September 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 St Albans if in doubt.
Boundary: St Albans City and District Council via planning.data.gov.uk (entity 44010114, reference CA11_6a, 5.8 ha); the council's appraisal or map. Homes are placed by the coordinates of their UPRN (OS Open UPRN); addresses are not shown.