Solar panels, heat pumps and insulation in Hampstead Garden Suburb conservation area
In the Hampstead Garden Suburb conservation area (Barnet), 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 Barnet covers this area and removes permitted development rights for solar panels on the house, ground source heat pumps, replacement windows and doors, and other alterations to the house, alterations to the roof (e.g. rooflights), painting the outside, so there these need planning permission too. The area has 290 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. 3,679 homes inside the boundary have an energy certificate: 72.8% are solid-wall homes with no wall insulation, 93.4% heat with a gas boiler and 75.6% are rated D–G; 41 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
3,679homes with an energy certificate
72.8%solid walls, no insulation
93.4%heated by a gas boiler
41heat pumps
Article 4: An Article 4 direction published by Barnet covers this area and removes permitted development rights for solar panels on the house, ground source heat pumps, replacement windows and doors, and other alterations to the house, alterations to the roof (e.g. rooflights), painting the outside, so there these need planning permission too. (Article 4 Small Houses in Multiple Occupation (HMO) Area 1; Article 4 for Hampstead Garden Suburb CA Area 1; Article 4 for Hampstead Garden Suburb CA Area 2 Spaniards End)
What needs planning permission in Hampstead Garden Suburb
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)
Planning permission needed (an Article 4 direction here removes this right)
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)
Planning permission needed (an Article 4 direction here removes this right)
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: 290 in the area (grade I: 2, II*: 18). 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: 40% 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 = 3,679)
Walls
Homes
Share
Solid wall (brick or stone), no insulation
2,677
72.8%
Cavity wall, unfilled
467
12.7%
Timber frame
120
3.3%
Cavity wall, insulated (as built or unspecified)
113
3.1%
Modern wall (U-value from the design)
105
2.9%
Solid wall, internal insulation
59
1.6%
Cavity wall, filled
53
1.4%
Solid wall, insulated
37
1.0%
Other or not known
25
0.7%
Cavity wall, partly insulated
13
0.4%
Cavity wall, internal or external insulation
8
0.2%
Solid wall, external insulation
1
0.0%
Solid wall, partly insulated
1
0.0%
Heating
Homes
Share
Gas boiler
3,437
93.4%
Communal heating
116
3.2%
Electric (storage heaters, panels, boiler)
80
2.2%
Heat pump
41
1.1%
LPG
3
0.1%
Solid fuel (wood, coal)
2
0.1%
Loft / roof insulation
Homes
Share
No insulation
1,127
30.6%
Under 200 mm
840
22.8%
200 mm or more
301
8.2%
Insulated (depth not recorded)
436
11.9%
Flat or other home above
884
24.0%
Other
90
2.4%
Windows
Homes
Share
Double glazed
1,488
40.4%
Single glazed
1,325
36.0%
Secondary glazing
861
23.4%
Triple glazed
5
0.1%
CDE
Energy rating: A 1 (0.0%) · B 115 (3.1%) · C 781 (21.2%) · D 1,767 (48.0%) · E 855 (23.2%) · F 147 (4.0%) · G 13 (0.4%). Houses and bungalows: 60% of the homes; solar panels on 0.0% of the certificates. Most common build period on the certificates: 1900-1929. Designated: 20 December 1968.
Compared with Barnet and England
Share of homes
Hampstead Garden Suburb
All 16 areas in Barnet
England
Solid walls, no insulation
72.8%
48.2%
48.7%
Gas boiler
93.4%
84.8%
66.4%
Rated D–G
75.6%
—
56.5%
Caveats
Certificates describe a home when it was assessed; 53% of these are from 2020 or later (latest 31 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 Barnet if in doubt.
Boundary: London Borough of Barnet via planning.data.gov.uk (entity 44004082, reference CA15, 409.6 ha); the council's appraisal or map. Homes are placed by the coordinates of their UPRN (OS Open UPRN); addresses are not shown.