Solar panels, heat pumps and insulation in Lancaster - Bath Mill conservation area
In the Lancaster - Bath Mill conservation area (Lancaster), 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 Lancaster covers this area and removes permitted development rights for replacement windows and doors, and other alterations to the house, painting the outside, so there these need planning permission too. 70 homes inside the boundary have an energy certificate: 0% are solid-wall homes with no wall insulation, 50% heat with a gas boiler and 43% 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
70homes with an energy certificate
0%solid walls, no insulation
50%heated by a gas boiler
0heat pumps
Article 4: An Article 4 direction published by Lancaster covers this area and removes permitted development rights for replacement windows and doors, and other alterations to the house, painting the outside, so there these need planning permission too. (Bath Mill)
What needs planning permission in Lancaster - Bath Mill
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
Planning permission needed (an Article 4 direction here removes this right)
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: 37% 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 = 70)
Walls
Homes
Share
Cavity wall, filled
57
81%
Cavity wall, unfilled
5
7%
Cavity wall, partly insulated
3
4%
Other or not known
2
3%
Timber frame
2
3%
Cavity wall, insulated (as built or unspecified)
1
1%
Heating
Homes
Share
Electric (storage heaters, panels, boiler)
35
50%
Gas boiler
35
50%
Loft / roof insulation
Homes
Share
No insulation
1
1%
Under 200 mm
10
14%
200 mm or more
46
66%
Flat or other home above
13
19%
Windows
Homes
Share
Double glazed
69
99%
Single glazed
1
1%
CD
Energy rating: C 40 (57%) · D 26 (37%) · E 3 (4%) · F 1 (1%). Houses and bungalows: 63% of the homes; solar panels on 0% of the certificates. Most common build period on the certificates: 1976-1982. Designated: 1 January 1983.
Compared with Lancaster and England
Share of homes
Lancaster - Bath Mill
All 38 areas in Lancaster
England
Solid walls, no insulation
0%
51.5%
48.7%
Gas boiler
50%
67.5%
66.4%
Rated D–G
43%
—
56.5%
Caveats
Certificates describe a home when it was assessed; 50% of these are from 2020 or later (latest 22 January 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 Lancaster if in doubt.
Boundary: Lancaster City Council via planning.data.gov.uk (entity 44016577, reference 1387, 1.9 ha); the council's appraisal or map. Homes are placed by the coordinates of their UPRN (OS Open UPRN); addresses are not shown.