Solar panels, heat pumps and insulation in Mallard Place conservation area
In the Mallard Place 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. 74 homes inside the boundary have an energy certificate: 0% are solid-wall homes with no wall insulation, 95% heat with a gas boiler and 47% are rated D–G; 0 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
74homes with an energy certificate
0%solid walls, no insulation
95%heated by a gas boiler
0heat 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 Mallard Place
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: none recorded inside the boundary; on a listed building, solar panels and heat pumps are not permitted development and need listed building consent.
Flats: 55% 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 = 74)
Walls
Homes
Share
Cavity wall, insulated (as built or unspecified)
31
42%
Cavity wall, partly insulated
20
27%
Other or not known
9
12%
Cavity wall, unfilled
6
8%
Timber frame
5
7%
Cavity wall, filled
2
3%
Solid wall, insulated
1
1%
Heating
Homes
Share
Gas boiler
70
95%
Electric (storage heaters, panels, boiler)
4
5%
Loft / roof insulation
Homes
Share
No insulation
1
1%
Under 200 mm
14
19%
200 mm or more
3
4%
Insulated (depth not recorded)
36
49%
Flat or other home above
19
26%
Other
1
1%
Windows
Homes
Share
Double glazed
56
76%
Single glazed
15
20%
Secondary glazing
3
4%
CD
Energy rating: C 39 (53%) · D 29 (39%) · E 5 (7%) · F 1 (1%). Houses and bungalows: 45% of the homes; solar panels on 0% of the certificates. Most common build period on the certificates: 1976-1982. Designated: 14 June 1988.
Compared with Richmond upon Thames and England
Share of homes
Mallard Place
All 85 areas in Richmond upon Thames
England
Solid walls, no insulation
0%
63.5%
48.7%
Gas boiler
95%
83.6%
66.4%
Rated D–G
47%
—
56.5%
Caveats
Certificates describe a home when it was assessed; 53% of these are from 2020 or later (latest 20 May 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 44002460, reference 7389, 2.3 ha); the council's appraisal or map. Homes are placed by the coordinates of their UPRN (OS Open UPRN); addresses are not shown.