Solar panels, heat pumps and insulation in Highwood Hospital, Brentwood conservation area
In the Highwood Hospital, Brentwood conservation area (Brentwood), 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. 122 homes inside the boundary have an energy certificate: 9.8% are solid-wall homes with no wall insulation, 99.2% heat with a gas boiler and 4.9% are rated D–G; 1 has 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
122homes with an energy certificate
9.8%solid walls, no insulation
99.2%heated by a gas boiler
1heat pumps
Article 4: Brentwood does not publish Article 4 areas on planning.data.gov.uk — check with the council.
What needs planning permission in Highwood Hospital, Brentwood
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: none recorded inside the boundary; on a listed building, solar panels and heat pumps are not permitted development and need listed building consent.
Flats: 20% 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 = 122)
Walls
Homes
Share
Modern wall (U-value from the design)
81
66.4%
Cavity wall, insulated (as built or unspecified)
15
12.3%
Solid wall (brick or stone), no insulation
12
9.8%
Solid wall, insulated
9
7.4%
Solid wall, internal insulation
4
3.3%
Solid wall, partly insulated
1
0.8%
Heating
Homes
Share
Gas boiler
121
99.2%
Heat pump
1
0.8%
Loft / roof insulation
Homes
Share
No insulation
5
4.1%
Under 200 mm
1
0.8%
200 mm or more
14
11.5%
Insulated (depth not recorded)
15
12.3%
Flat or other home above
6
4.9%
Other
81
66.4%
Windows
Homes
Share
Double glazed
122
100.0%
BC
Energy rating: B 44 (36.1%) · C 72 (59.0%) · D 5 (4.1%) · E 1 (0.8%). Houses and bungalows: 80% of the homes; solar panels on 4.9% of the certificates. Most common build period on the certificates: 2012. Designated: 12 July 2001.
Compared with Brentwood and England
Share of homes
Highwood Hospital, Brentwood
All 13 areas in Brentwood
England
Solid walls, no insulation
9.8%
26.2%
48.7%
Gas boiler
99.2%
66.2%
66.4%
Rated D–G
4.9%
—
56.5%
Caveats
Certificates describe a home when it was assessed; 33% of these are from 2020 or later (latest 27 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 Brentwood if in doubt.
Boundary: Brentwood Borough Council via planning.data.gov.uk (entity 44001669, reference 8499, 5.2 ha); the council's appraisal or map. Homes are placed by the coordinates of their UPRN (OS Open UPRN); addresses are not shown.