Solar panels, heat pumps and insulation in Derwent Square conservation area
In the Derwent Square conservation area (Liverpool), 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 Liverpool covers part of this area (about 1% of it) and removes permitted development rights for replacement windows and doors, and other alterations to the house, alterations to the roof (e.g. rooflights), chimneys, flues and soil pipes, so there these need planning permission too. 247 homes inside the boundary have an energy certificate: 85.0% are solid-wall homes with no wall insulation, 99.2% heat with a gas boiler and 67.6% 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
247homes with an energy certificate
85.0%solid walls, no insulation
99.2%heated by a gas boiler
0heat pumps
Article 4: An Article 4 direction published by Liverpool covers part of this area (about 1% of it) and removes permitted development rights for replacement windows and doors, and other alterations to the house, alterations to the roof (e.g. rooflights), chimneys, flues and soil pipes, so there these need planning permission too. (100a Sandstone Road, L13)
What needs planning permission in Derwent Square
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
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: none recorded inside the boundary; on a listed building, solar panels and heat pumps are not permitted development and need listed building consent.
Flats: 41% 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
210
85.0%
Solid wall, partly insulated
13
5.3%
Cavity wall, insulated (as built or unspecified)
8
3.2%
Cavity wall, filled
7
2.8%
Solid wall, internal insulation
4
1.6%
Cavity wall, unfilled
2
0.8%
Timber frame
2
0.8%
Modern wall (U-value from the design)
1
0.4%
Heating
Homes
Share
Gas boiler
245
99.2%
Electric (storage heaters, panels, boiler)
1
0.4%
Solid fuel (wood, coal)
1
0.4%
Loft / roof insulation
Homes
Share
No insulation
57
23.1%
Under 200 mm
42
17.0%
200 mm or more
69
27.9%
Insulated (depth not recorded)
20
8.1%
Flat or other home above
58
23.5%
Other
1
0.4%
Windows
Homes
Share
Double glazed
212
85.8%
Single glazed
33
13.4%
Secondary glazing
2
0.8%
CDE
Energy rating: B 2 (0.8%) · C 78 (31.6%) · D 137 (55.5%) · E 27 (10.9%) · F 1 (0.4%) · G 2 (0.8%). Houses and bungalows: 59% of the homes; solar panels on 0.4% of the certificates. Most common build period on the certificates: before 1900. Designated: 8 April 1981.
Compared with Liverpool and England
Share of homes
Derwent Square
All 37 areas in Liverpool
England
Solid walls, no insulation
85.0%
41.6%
48.7%
Gas boiler
99.2%
53.3%
66.4%
Rated D–G
67.6%
—
56.5%
Caveats
Certificates describe a home when it was assessed; 60% of these are from 2020 or later (latest 21 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 Liverpool if in doubt.
Boundary: Liverpool City Council via planning.data.gov.uk (entity 44014327, reference CA005, 6.7 ha). Homes are placed by the coordinates of their UPRN (OS Open UPRN); addresses are not shown.