Solar panels, heat pumps and insulation in St Matthias conservation area
In the St Matthias conservation area (Richmond upon Thames), 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. 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. 1,800 homes inside the boundary have an energy certificate: 77.5% are solid-wall homes with no wall insulation, 92.2% heat with a gas boiler and 67.2% are rated D–G; 13 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
1,800homes with an energy certificate
77.5%solid walls, no insulation
92.2%heated by a gas boiler
13heat pumps
Article 4: Richmond upon Thames does not publish Article 4 areas on planning.data.gov.uk — check with the council.
What needs planning permission in St Matthias
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), unless an Article 4 direction removes it — check with the council
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), unless an Article 4 direction removes it — check with the council
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)
Prior approval of appearance from the council, unless an Article 4 direction removes it — check with the council
Replacement windows and doors of similar appearance
No permission needed (permitted development), unless an Article 4 direction removes it — check with the council
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: 59% 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 = 1,800)
Walls
Homes
Share
Solid wall (brick or stone), no insulation
1,395
77.5%
Cavity wall, unfilled
133
7.4%
Cavity wall, insulated (as built or unspecified)
83
4.6%
Timber frame
45
2.5%
Cavity wall, partly insulated
42
2.3%
Solid wall, internal insulation
28
1.6%
Modern wall (U-value from the design)
26
1.4%
Other or not known
16
0.9%
Solid wall, insulated
16
0.9%
Cavity wall, filled
8
0.4%
Cavity wall, internal or external insulation
5
0.3%
Solid wall, partly insulated
3
0.2%
Heating
Homes
Share
Gas boiler
1,659
92.2%
Electric (storage heaters, panels, boiler)
95
5.3%
Communal heating
31
1.7%
Heat pump
13
0.7%
LPG
2
0.1%
Loft / roof insulation
Homes
Share
No insulation
328
18.2%
Under 200 mm
315
17.5%
200 mm or more
115
6.4%
Insulated (depth not recorded)
269
14.9%
Flat or other home above
749
41.6%
Other
24
1.3%
Windows
Homes
Share
Double glazed
1,274
70.8%
Single glazed
482
26.8%
Secondary glazing
41
2.3%
Triple glazed
3
0.2%
CDE
Energy rating: A 3 (0.2%) · B 20 (1.1%) · C 567 (31.5%) · D 862 (47.9%) · E 300 (16.7%) · F 42 (2.3%) · G 6 (0.3%). Houses and bungalows: 41% of the homes; solar panels on 0.2% of the certificates. Most common build period on the certificates: before 1900. Designated: 5 July 1977.
Compared with Richmond upon Thames and England
Share of homes
St Matthias
All 85 areas in Richmond upon Thames
England
Solid walls, no insulation
77.5%
63.5%
48.7%
Gas boiler
92.2%
83.6%
66.4%
Rated D–G
67.2%
—
56.5%
Caveats
Certificates describe a home when it was assessed; 53% 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 Richmond upon Thames if in doubt.
Boundary: London Borough of Richmond upon Thames via planning.data.gov.uk (entity 44002488, reference 7375, 45.3 ha); the council's appraisal or map. Homes are placed by the coordinates of their UPRN (OS Open UPRN); addresses are not shown.