Solar panels, heat pumps and insulation in De Freville conservation area
In the De Freville conservation area (Cambridge), 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. 373 homes inside the boundary have an energy certificate: 77.5% are solid-wall homes with no wall insulation, 83.6% heat with a gas boiler and 75.3% are rated D–G; 5 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
373homes with an energy certificate
77.5%solid walls, no insulation
83.6%heated by a gas boiler
5heat pumps
Article 4: Cambridge publishes its Article 4 areas on planning.data.gov.uk and none overlaps this area; a direction can still exist on paper, so check with the council.
What needs planning permission in De Freville
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
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: 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 = 373)
Walls
Homes
Share
Solid wall (brick or stone), no insulation
289
77.5%
Cavity wall, insulated (as built or unspecified)
38
10.2%
Timber frame
13
3.5%
Solid wall, internal insulation
9
2.4%
Modern wall (U-value from the design)
8
2.1%
Cavity wall, filled
7
1.9%
Cavity wall, partly insulated
3
0.8%
Cavity wall, unfilled
3
0.8%
Other or not known
1
0.3%
Solid wall, external insulation
1
0.3%
Solid wall, insulated
1
0.3%
Heating
Homes
Share
Gas boiler
312
83.6%
Electric (storage heaters, panels, boiler)
46
12.3%
Communal heating
10
2.7%
Heat pump
5
1.3%
Loft / roof insulation
Homes
Share
No insulation
107
28.7%
Under 200 mm
69
18.5%
200 mm or more
69
18.5%
Insulated (depth not recorded)
75
20.1%
Flat or other home above
45
12.1%
Other
8
2.1%
Windows
Homes
Share
Double glazed
322
86.3%
Single glazed
34
9.1%
Secondary glazing
15
4.0%
Triple glazed
2
0.5%
CDE
Energy rating: B 17 (4.6%) · C 75 (20.1%) · D 176 (47.2%) · E 91 (24.4%) · F 11 (2.9%) · G 3 (0.8%). Houses and bungalows: 80% of the homes; solar panels on 1.6% of the certificates. Most common build period on the certificates: 1900-1929. Designated: 3 March 2009.
Compared with Cambridge and England
Share of homes
De Freville
All 18 areas in Cambridge
England
Solid walls, no insulation
77.5%
52.2%
48.7%
Gas boiler
83.6%
71.7%
66.4%
Rated D–G
75.3%
—
56.5%
Caveats
Certificates describe a home when it was assessed; 53% of these are from 2020 or later (latest 26 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 Cambridge if in doubt.
Boundary: Cambridge City Council via planning.data.gov.uk (entity 44002384, reference 27, 17.9 ha); the council's appraisal or map. Homes are placed by the coordinates of their UPRN (OS Open UPRN); addresses are not shown.