Solar panels, heat pumps and insulation in Barbican conservation area
In the Barbican conservation area (Plymouth), 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 Plymouth covers this area but deals with other things (such as changes of use); it does not change the rules below. The area has 108 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. 1,096 homes inside the boundary have an energy certificate: 30.5% are solid-wall homes with no wall insulation, 64.9% heat with a gas boiler and 41.8% are rated D–G; 1 has 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
1,096homes with an energy certificate
30.5%solid walls, no insulation
64.9%heated by a gas boiler
1heat pumps
Article 4: An Article 4 direction published by Plymouth covers this area but deals with other things (such as changes of use); it does not change the rules below. (HMOs Mutley, Greenbank, City Centre and surrounding areas)
What needs planning permission in Barbican
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: 108 in the area (grade I: 2, II*: 10). 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: 94% 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 = 1,096)
Walls
Homes
Share
Solid wall (brick or stone), no insulation
334
30.5%
Cavity wall, insulated (as built or unspecified)
150
13.7%
Cavity wall, filled
147
13.4%
Cavity wall, unfilled
139
12.7%
Other or not known
97
8.9%
Solid wall, insulated
65
5.9%
Timber frame
36
3.3%
Cavity wall, partly insulated
31
2.8%
Modern wall (U-value from the design)
29
2.6%
Solid wall, internal insulation
28
2.6%
Cavity wall, internal or external insulation
26
2.4%
Solid wall, partly insulated
10
0.9%
Solid wall, external insulation
4
0.4%
Heating
Homes
Share
Gas boiler
711
64.9%
Electric (storage heaters, panels, boiler)
333
30.4%
Communal heating
49
4.5%
Heat pump
1
0.1%
LPG
1
0.1%
Solid fuel (wood, coal)
1
0.1%
Loft / roof insulation
Homes
Share
No insulation
102
9.3%
Under 200 mm
101
9.2%
200 mm or more
92
8.4%
Insulated (depth not recorded)
121
11.0%
Flat or other home above
664
60.6%
Other
16
1.5%
Windows
Homes
Share
Double glazed
895
81.7%
Single glazed
154
14.1%
Secondary glazing
43
3.9%
Triple glazed
4
0.4%
CDE
Energy rating: B 79 (7.2%) · C 559 (51.0%) · D 324 (29.6%) · E 112 (10.2%) · F 15 (1.4%) · G 7 (0.6%). Houses and bungalows: 6% of the homes; solar panels on 0.0% of the certificates. Most common build period on the certificates: before 1900. Designated: 1 February 2007.
Compared with Plymouth and England
Share of homes
Barbican
All 16 areas in Plymouth
England
Solid walls, no insulation
30.5%
44.9%
48.7%
Gas boiler
64.9%
69.8%
66.4%
Rated D–G
41.8%
—
56.5%
Caveats
Certificates describe a home when it was assessed; 52% of these are from 2020 or later (latest 29 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 Plymouth if in doubt.
Boundary: Plymouth City Council via planning.data.gov.uk (entity 44012317, reference CON10, 19.3 ha); the council's appraisal or map. Homes are placed by the coordinates of their UPRN (OS Open UPRN); addresses are not shown.