Solar panels, heat pumps and insulation in St Albans - St Peters Park and the Marlborough House Estate conservation area
In the St Albans - St Peters Park and the Marlborough House Estate 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. 1,061 homes inside the boundary have an energy certificate: 13.3% are solid-wall homes with no wall insulation, 72.1% heat with a gas boiler and 32.8% are rated D–G; 3 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
1,061homes with an energy certificate
13.3%solid walls, no insulation
72.1%heated by a gas boiler
3heat pumps
Article 4: St Albans publishes its Article 4 areas on planning.data.gov.uk and none overlaps this area; a direction can still exist on paper, so check with the council.
What needs planning permission in St Albans - St Peters Park and the Marlborough House Estate
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: 86% 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 = 1,061)
Walls
Homes
Share
Cavity wall, insulated (as built or unspecified)
220
20.7%
Modern wall (U-value from the design)
183
17.2%
Other or not known
170
16.0%
Solid wall (brick or stone), no insulation
141
13.3%
Cavity wall, filled
129
12.2%
Cavity wall, unfilled
116
10.9%
Timber frame
52
4.9%
Cavity wall, partly insulated
33
3.1%
Solid wall, internal insulation
9
0.8%
Solid wall, insulated
8
0.8%
Heating
Homes
Share
Gas boiler
765
72.1%
Electric (storage heaters, panels, boiler)
204
19.2%
Communal heating
88
8.3%
Heat pump
3
0.3%
LPG
1
0.1%
Loft / roof insulation
Homes
Share
No insulation
31
2.9%
Under 200 mm
103
9.7%
200 mm or more
67
6.3%
Insulated (depth not recorded)
166
15.6%
Flat or other home above
616
58.1%
Other
78
7.4%
Windows
Homes
Share
Double glazed
957
90.2%
Single glazed
75
7.1%
Secondary glazing
27
2.5%
Triple glazed
2
0.2%
BCDE
Energy rating: B 262 (24.7%) · C 451 (42.5%) · D 238 (22.4%) · E 100 (9.4%) · F 9 (0.8%) · G 1 (0.1%). Houses and bungalows: 14% of the homes; solar panels on 0.0% of the certificates. Most common build period on the certificates: 2007-2011. Designated: 24 March 1969.
Compared with St Albans and England
Share of homes
St Albans - St Peters Park and the Marlborough House Estate
All 45 areas in St Albans
England
Solid walls, no insulation
13.3%
37.1%
48.7%
Gas boiler
72.1%
76.8%
66.4%
Rated D–G
32.8%
—
56.5%
Caveats
Certificates describe a home when it was assessed; 58% of these are from 2020 or later (latest 19 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 St Albans if in doubt.
Boundary: St Albans City and District Council via planning.data.gov.uk (entity 44010085, reference CA11_7f, 32.5 ha); the council's appraisal or map. Homes are placed by the coordinates of their UPRN (OS Open UPRN); addresses are not shown.