Solar panels, heat pumps and insulation in Underwood Street conservation area
In the Underwood Street conservation area (Hackney), 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 Hackney covers this area but deals with other things (such as changes of use); it does not change the rules below. 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. 247 homes inside the boundary have an energy certificate: 46.6% are solid-wall homes with no wall insulation, 73.7% heat with a gas boiler and 18.6% are rated D–G; 12 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
247homes with an energy certificate
46.6%solid walls, no insulation
73.7%heated by a gas boiler
12heat pumps
Article 4: An Article 4 direction published by Hackney covers this area but deals with other things (such as changes of use); it does not change the rules below. (A4D Non-residential to residential; Hackney Central Activity Zone; London borough of Hackney; Tech City (CAZ North))
What needs planning permission in Underwood 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)
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
No permission needed (permitted development)
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: 100% 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 = 247)
Walls
Homes
Share
Solid wall (brick or stone), no insulation
115
46.6%
Solid wall, insulated
48
19.4%
Modern wall (U-value from the design)
24
9.7%
Other or not known
23
9.3%
Cavity wall, insulated (as built or unspecified)
21
8.5%
Timber frame
10
4.0%
Solid wall, internal insulation
3
1.2%
Solid wall, partly insulated
2
0.8%
Cavity wall, unfilled
1
0.4%
Heating
Homes
Share
Gas boiler
182
73.7%
Communal heating
29
11.7%
Electric (storage heaters, panels, boiler)
24
9.7%
Heat pump
12
4.9%
Loft / roof insulation
Homes
Share
No insulation
14
5.7%
Under 200 mm
1
0.4%
Insulated (depth not recorded)
34
13.8%
Flat or other home above
186
75.3%
Other
12
4.9%
Windows
Homes
Share
Double glazed
211
85.4%
Single glazed
34
13.8%
Secondary glazing
2
0.8%
BCD
Energy rating: B 44 (17.8%) · C 157 (63.6%) · D 34 (13.8%) · E 9 (3.6%) · F 2 (0.8%) · G 1 (0.4%). Houses and bungalows: 0% of the homes; solar panels on 0.0% of the certificates. Most common build period on the certificates: 1900-1929. Designated: 1 January 1990.
Compared with Hackney and England
Share of homes
Underwood Street
All 37 areas in Hackney
England
Solid walls, no insulation
46.6%
50.5%
48.7%
Gas boiler
73.7%
70.8%
66.4%
Rated D–G
18.6%
—
56.5%
Caveats
Certificates describe a home when it was assessed; 55% of these are from 2020 or later (latest 14 August 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 Hackney if in doubt.
Boundary: London Borough of Hackney via planning.data.gov.uk (entity 44016009, reference CA21, 3.5 ha); the council's appraisal or map. Homes are placed by the coordinates of their UPRN (OS Open UPRN); addresses are not shown.