Solar panels, heat pumps and insulation in Old Harlow conservation area
In the Old Harlow conservation area (Harlow), 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 Harlow covers this area and removes permitted development rights for solar panels on the house, replacement windows and doors, and other alterations to the house, alterations to the roof (e.g. rooflights), chimneys, flues and soil pipes, painting the outside, so there these need planning permission too. The area has 37 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. 347 homes inside the boundary have an energy certificate: 41.8% are solid-wall homes with no wall insulation, 80.4% heat with a gas boiler and 60.5% 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
347homes with an energy certificate
41.8%solid walls, no insulation
80.4%heated by a gas boiler
0heat pumps
Article 4: An Article 4 direction published by Harlow covers this area and removes permitted development rights for solar panels on the house, replacement windows and doors, and other alterations to the house, alterations to the roof (e.g. rooflights), chimneys, flues and soil pipes, painting the outside, so there these need planning permission too. (HMO - townwide; High Street- 79-97 (odds); Old Harlow (Bury Road, New Road, High Street and Old Road); Park Hill and Mulberry Terrace)
What needs planning permission in Old Harlow
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: 37 in the area (grade I: 0, II*: 3). 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: 32% 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 = 347)
Walls
Homes
Share
Solid wall (brick or stone), no insulation
145
41.8%
Modern wall (U-value from the design)
47
13.5%
Cavity wall, filled
46
13.3%
Timber frame
34
9.8%
Cavity wall, insulated (as built or unspecified)
27
7.8%
Cavity wall, unfilled
26
7.5%
Other or not known
13
3.7%
Cavity wall, partly insulated
4
1.2%
Solid wall, insulated
2
0.6%
Cavity wall, internal or external insulation
1
0.3%
Solid wall, external insulation
1
0.3%
Solid wall, internal insulation
1
0.3%
Heating
Homes
Share
Gas boiler
279
80.4%
Communal heating
32
9.2%
Electric (storage heaters, panels, boiler)
24
6.9%
Oil
11
3.2%
LPG
1
0.3%
Loft / roof insulation
Homes
Share
No insulation
43
12.4%
Under 200 mm
72
20.7%
200 mm or more
109
31.4%
Insulated (depth not recorded)
39
11.2%
Flat or other home above
41
11.8%
Other
43
12.4%
Windows
Homes
Share
Double glazed
278
80.1%
Single glazed
52
15.0%
Secondary glazing
14
4.0%
Other
3
0.9%
BCDE
Energy rating: B 34 (9.8%) · C 103 (29.7%) · D 142 (40.9%) · E 57 (16.4%) · F 11 (3.2%). Houses and bungalows: 68% of the homes; solar panels on 0.3% of the certificates. Most common build period on the certificates: before 1900. Designated: 1 January 1969.
Compared with Harlow and England
Share of homes
Old Harlow
All 10 areas in Harlow
England
Solid walls, no insulation
41.8%
26.1%
48.7%
Gas boiler
80.4%
83.5%
66.4%
Rated D–G
60.5%
—
56.5%
Caveats
Certificates describe a home when it was assessed; 60% of these are from 2020 or later (latest 28 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 Harlow if in doubt.
Boundary: Harlow District Council via planning.data.gov.uk (entity 44015564, reference HAR_CA7, 16.7 ha); the council's appraisal or map. Homes are placed by the coordinates of their UPRN (OS Open UPRN); addresses are not shown.