Solar panels, heat pumps and insulation in Hollingbourne, Eyhorne Street conservation area
In the Hollingbourne, Eyhorne Street conservation area (Maidstone), 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 Maidstone covers this area, but the published data does not say which rights it removes — check the direction before any work. The area has 26 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. 53 homes inside the boundary have an energy certificate: 68% are solid-wall homes with no wall insulation, 94% heat with a gas boiler and 75% 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
53homes with an energy certificate
68%solid walls, no insulation
94%heated by a gas boiler
0heat pumps
Article 4: An Article 4 direction published by Maidstone covers this area, but the published data does not say which rights it removes — check the direction before any work. (Eyhorne Farm,; Land at Eyhorne Farm)
What needs planning permission in Hollingbourne, Eyhorne 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), unless an Article 4 direction removes it — check with the council
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), unless an Article 4 direction removes it — check with the council
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)
Prior approval of appearance from the council, unless an Article 4 direction removes it — check with the council
Replacement windows and doors of similar appearance
No permission needed (permitted development), unless an Article 4 direction removes it — check with the council
Part 1 Class A, A.3(a)
Listed buildings: 26 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: 11% 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 = 53)
Walls
Homes
Share
Solid wall (brick or stone), no insulation
36
68%
Modern wall (U-value from the design)
7
13%
Solid wall, internal insulation
3
6%
Timber frame
3
6%
Cavity wall, insulated (as built or unspecified)
2
4%
Cavity wall, filled
1
2%
Other or not known
1
2%
Heating
Homes
Share
Gas boiler
50
94%
Electric (storage heaters, panels, boiler)
2
4%
Oil
1
2%
Loft / roof insulation
Homes
Share
No insulation
17
32%
Under 200 mm
15
28%
200 mm or more
4
8%
Insulated (depth not recorded)
9
17%
Flat or other home above
1
2%
Other
7
13%
Windows
Homes
Share
Single glazed
25
47%
Double glazed
24
45%
Secondary glazing
4
8%
BCDE
Energy rating: B 6 (11%) · C 7 (13%) · D 22 (42%) · E 15 (28%) · F 3 (6%). Houses and bungalows: 89% of the homes; solar panels on 2% of the certificates. Most common build period on the certificates: before 1900. Designated: 24 November 1977.
Compared with Maidstone and England
Share of homes
Hollingbourne, Eyhorne Street
All 48 areas in Maidstone
England
Solid walls, no insulation
68%
43.3%
48.7%
Gas boiler
94%
66.3%
66.4%
Rated D–G
75%
—
56.5%
Caveats
Certificates describe a home when it was assessed; 60% of these are from 2020 or later (latest 7 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 Maidstone if in doubt.
Boundary: Maidstone Borough Council via planning.data.gov.uk (entity 44016624, reference CA-MAI-16, 4.4 ha); the council's appraisal or map. Homes are placed by the coordinates of their UPRN (OS Open UPRN); addresses are not shown.