Solar panels, heat pumps and insulation in Portchester Castle Street conservation area
In the Portchester Castle Street conservation area (Fareham), 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 Fareham covers part of this area (about 14% of it) and removes permitted development rights for solar panels on the house, wind turbines on the house, 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 51 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. 105 homes inside the boundary have an energy certificate: 23.8% are solid-wall homes with no wall insulation, 92.4% heat with a gas boiler and 59.0% 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
105homes with an energy certificate
23.8%solid walls, no insulation
92.4%heated by a gas boiler
3heat pumps
Article 4: An Article 4 direction published by Fareham covers part of this area (about 14% of it) and removes permitted development rights for solar panels on the house, wind turbines on the house, 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. (Portchester)
What needs planning permission in Portchester Castle Street
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)
Inside the Article 4 part of the area: planning permission needed; elsewhere: 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)
Inside the Article 4 part of the area: planning permission needed; elsewhere: prior approval of appearance from the council
Replacement windows and doors of similar appearance
Inside the Article 4 part of the area: planning permission needed; elsewhere: no permission needed (permitted development)
Part 1 Class A, A.3(a)
Listed buildings: 51 in the area (grade I: 2, II*: 0). 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: 8% 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 = 105)
Walls
Homes
Share
Cavity wall, unfilled
25
23.8%
Solid wall (brick or stone), no insulation
25
23.8%
Cavity wall, filled
22
21.0%
Cavity wall, insulated (as built or unspecified)
22
21.0%
Modern wall (U-value from the design)
4
3.8%
Cavity wall, internal or external insulation
2
1.9%
Timber frame
2
1.9%
Cavity wall, partly insulated
1
1.0%
Solid wall, external insulation
1
1.0%
Solid wall, internal insulation
1
1.0%
Heating
Homes
Share
Gas boiler
97
92.4%
Electric (storage heaters, panels, boiler)
4
3.8%
Heat pump
3
2.9%
Oil
1
1.0%
Loft / roof insulation
Homes
Share
No insulation
13
12.4%
Under 200 mm
29
27.6%
200 mm or more
36
34.3%
Insulated (depth not recorded)
20
19.0%
Flat or other home above
2
1.9%
Other
5
4.8%
Windows
Homes
Share
Double glazed
94
89.5%
Single glazed
8
7.6%
Secondary glazing
3
2.9%
CDE
Energy rating: B 3 (2.9%) · C 40 (38.1%) · D 41 (39.0%) · E 15 (14.3%) · F 6 (5.7%). Houses and bungalows: 92% of the homes; solar panels on 0.0% of the certificates. Most common build period on the certificates: before 1900. Designated: 1 January 1969.
Compared with Fareham and England
Share of homes
Portchester Castle Street
All 13 areas in Fareham
England
Solid walls, no insulation
23.8%
28.7%
48.7%
Gas boiler
92.4%
78.9%
66.4%
Rated D–G
59.0%
—
56.5%
Caveats
Certificates describe a home when it was assessed; 48% 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 Fareham if in doubt.
Boundary: Fareham Borough Council via planning.data.gov.uk (entity 44015923, reference 67, 36.2 ha); the council's appraisal or map. Homes are placed by the coordinates of their UPRN (OS Open UPRN); addresses are not shown.