Solar panels, heat pumps and insulation in Portswood Residents' Gardens conservation area
In the Portswood Residents' Gardens conservation area (Southampton), 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 Southampton covers this area and removes permitted development rights for replacement windows and doors, and other alterations to the house, alterations to the roof (e.g. rooflights), chimneys, flues and soil pipes, painting the outside, so there these need planning permission too. The area has 1 listed building; on a listed building solar panels and heat pumps are not permitted development at all and need planning permission and listed building consent. 54 homes inside the boundary have an energy certificate: 6% are solid-wall homes with no wall insulation, 96% heat with a gas boiler and 80% 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
54homes with an energy certificate
6%solid walls, no insulation
96%heated by a gas boiler
1heat pumps
Article 4: An Article 4 direction published by Southampton covers this area and removes permitted development rights for replacement windows and doors, and other alterations to the house, alterations to the roof (e.g. rooflights), chimneys, flues and soil pipes, painting the outside, so there these need planning permission too. (HMO; Portswood Residents' Gardens Conservation Area)
What needs planning permission in Portswood Residents' Gardens
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
Planning permission needed (an Article 4 direction here removes this right)
Part 1 Class A, A.3(a)
Listed buildings: 1 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: 4% 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 = 54)
Walls
Homes
Share
Cavity wall, unfilled
26
48%
Cavity wall, filled
21
39%
Cavity wall, insulated (as built or unspecified)
3
6%
Solid wall (brick or stone), no insulation
3
6%
Cavity wall, partly insulated
1
2%
Heating
Homes
Share
Gas boiler
52
96%
Heat pump
1
2%
Solid fuel (wood, coal)
1
2%
Loft / roof insulation
Homes
Share
No insulation
8
15%
Under 200 mm
20
37%
200 mm or more
22
41%
Insulated (depth not recorded)
4
7%
Windows
Homes
Share
Double glazed
44
81%
Secondary glazing
5
9%
Single glazed
5
9%
CDE
Energy rating: C 11 (20%) · D 31 (57%) · E 9 (17%) · F 3 (6%). Houses and bungalows: 96% of the homes; solar panels on 7% of the certificates. Most common build period on the certificates: 1900-1929. Designated: 21 October 1996.
Compared with Southampton and England
Share of homes
Portswood Residents' Gardens
All 21 areas in Southampton
England
Solid walls, no insulation
6%
16.0%
48.7%
Gas boiler
96%
42.8%
66.4%
Rated D–G
80%
—
56.5%
Caveats
Certificates describe a home when it was assessed; 52% of these are from 2020 or later (latest 20 February 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 Southampton if in doubt.
Boundary: Southampton City Council via planning.data.gov.uk (entity 44015934, reference 138, 14.0 ha). Homes are placed by the coordinates of their UPRN (OS Open UPRN); addresses are not shown.