Retrofit feasibility study · London
Homes in listed buildings across London
The questionWhat does retrofit look like for homes in London's listed buildings, where most fabric changes need listed building consent?
53.0% of certified homes in London's listed buildings are rated D or worse and 41.5% are single glazed. The two most frequent recommendations, wall insulation and double glazing, normally need listed building consent.
- Certified homes
- 45,763
- latest certificate per address
- Below band C
- 53.0%
- rated D to G
- Single glazed
- 41.5%
- 9.2% of all certified London homes
- Potential C or better
- 73.7%
- of those below C
How the archetype was selected
London domestic units whose building record is flagged listed: the unit's centroid lies within 5 m of a Historic England NHLE listed-building polygon, or its footprint overlaps one by at least half of the smaller area. Coverage is counted at unit level. The rating profile uses the most recently lodged RdSAP/SAP certificate per address in any flagged unit, including a small number of units the stock model classes as non-domestic that hold domestic certificates.
Key figures
Data month: 2026-09 (lodgements to 2026-09-09; NHLE polygons pulled 2026-09-12). Shares are of the certified addresses in this archetype unless the row says otherwise.
| Band | Certificates | Share |
|---|---|---|
| A to B | 2,456 | 5.4% |
| C | 19,043 | 41.6% |
| D | 16,920 | 37.0% |
| E | 6,210 | 13.6% |
| F | 855 | 1.9% |
| G | 279 | 0.6% |
| Measure | Value |
|---|---|
| Domestic units in listed buildings | 15,845 (grade II 14,912; II* 691; I 242) |
| Units with only a modelled rating | 5,153 (32.5%), not used below |
| Certified homes | 45,763 latest certificates in 13,035 units |
| Below band C (D to G) | 24,264 (53.0%) |
| Below band E (F or G) | 1,134 (2.5%) |
| Certificate within 10-year validity at 22 October 2026 | 76.2% |
| Below C with a potential rating of C or better | 17,888 (73.7% of those below C) |
| Measure | Value |
|---|---|
| All grades | 10,673 (67.4%) |
| Grade II | 10,163 of 14,912 (68.2%) |
| Grade II* | 400 of 691 (57.9%) |
| Grade I | 110 of 242 (45.5%) |
| Measure | Value |
|---|---|
| Also in a conservation area | 36,973 (80.8%) |
| Grade II | 42,085 (92.0%) |
| Grade I or II* | 3,678 (8.0%) |
| Measure | Value |
|---|---|
| Single glazed | 41.5% (London certified homes: 9.2%) |
| Secondary glazing | 11.9% |
| Solid wall | 73.2% |
| Solid wall, no insulation | 65.7% |
| Electric main fuel | 19.3% |
| Measure | Value |
|---|---|
| Tenure recorded | 37,690 (82.4%) |
| Privately rented | 16,362 (43.4%) |
| Owner-occupied | 40.8% |
| Social rented | 15.8% |
| Measure | Value |
|---|---|
| F or G: below the E floor in law | 177 (1.1%) |
| Below C: the 2030 standard (confirmed policy, not yet law) | 8,179 (50.0%) |
| Borough | Certificates | Below C |
|---|---|---|
| Westminster | 11,113 | 46.6% |
| Kensington and Chelsea | 4,968 | 64.4% |
| Camden | 4,230 | 50.5% |
| Tower Hamlets | 3,677 | 47.1% |
| Southwark | 3,411 | 49.7% |
| Recommendation | Code | Certificates | Share | Most common cost text, as lodged |
|---|---|---|---|---|
| 50 mm internal or external wall insulation | 7 | 29,379 | 64.2% | £4,000 - £14,000 (78.1% of rows) |
| Replace single glazed windows with low-E double glazed windows | 8 | 23,533 | 51.4% | £3,300 - £6,500 (79.8% of rows) |
| Low energy lighting for all fixed outlets | 35 | 17,117 | 37.4% | £15 (cost text varies by certificate) (8% of rows) |
| Draught proof single-glazed windows | 10 | 10,814 | 23.6% | £80 - £120 (78.1% of rows) |
| Solar photovoltaic panels, 2.5 kWp | 34 | 6,692 | 14.6% | £3,500 - £5,500 (42.6% of rows) |
| Flat roof or sloping ceiling insulation | 45 | 4,516 | 9.9% | £850 - £1,500 (82.4% of rows) |
| Replace boiler with new condensing boiler | 20 | 4,343 | 9.5% | £2,200 - £3,000 (74% of rows) |
| Upgrade heating controls | 11-15 | 4,144 | 9.1% | £350 - £450 (66.9% of rows) |
Shares count certificates carrying the recommendation; across London, rows are loaded for 79-97% of the latest domestic certificates, depending on lodgement year, so these shares are lower bounds. Cost text is shown exactly as lodged, with the share of rows that carry it. It varies with the register version and is not a current price.
Findings
- London has 15,845 domestic units in listed buildings. 67.4% hold a lodged certificate, falling to 57.9% for grade II* and 45.5% for grade I.
- 53.0% of the 45,763 certified listed homes are rated D or worse, close to the London figure of 49.6%. Only 73.7% of those below C show a potential of C or better, against 83.3% for conservation-area terraces.
- 41.5% are single glazed, against 9.2% of all certified London homes. The two most frequent recommendations are wall insulation (64.2%) and double glazing (51.4%), and both normally need listed building consent.
- 80.8% of these certified listed homes also sit in a conservation area, so both regimes usually apply at once.
- 43.4% of listed homes with a known tenure were lodged as privately rented. 8,179 of them (50.0%) fall below the 2030 band C standard (confirmed policy, not yet law).
What it means for feasibility
Consents
Listed building consent is required for any work that affects a listed building's character, inside or out, which usually includes internal and external wall insulation, window replacement, roof-mounted PV and visible plant. BuildGrade's screening rules never offer external wall insulation, cavity wall insulation or double glazing for a listed building. Secondary glazing, draught-proofing, lighting, controls and like-for-like boiler replacement are the measures most often achievable, though secondary glazing and draught-proofing can still need consent depending on the fabric affected. This is general context for England, not legal advice.
Sequencing
- Confirm the list entry and grade first. 80.8% of these homes are also in a conservation area, so both regimes usually apply.
- Start with the measures most often achievable: secondary glazing, draught-proofing, lighting, heating controls and like-for-like boiler replacement, checking with the conservation officer whether the fabric affected needs consent.
- Plan wall insulation, window replacement, roof-mounted PV and visible plant as listed building consent applications, early, because they set the programme.
- Set the target with care: only 73.7% of the below-C homes show a potential of C or better even if every recommended measure were installed.
Planning statements are general context for England, not legal advice. Article 4 directions vary by borough and were not checked for these figures.
Sources
- MHCLG Energy Performance of Buildings register, domestic certificates and recommendations, lodgements to 2026-09-09 (non-address fields OGL v3)
- Historic England National Heritage List for England listed-building polygons, OGL v3, pulled 2026-09-12
- GLA London Datastore Conservation Areas, OGL v3, imported 2026-09-12
- GLA London Building Stock Model, OGL v3, imported 2026-09-12
- BuildGrade retrofit screening rules, version 1 (external wall insulation, cavity wall insulation and double glazing excluded for listed buildings)
Data month September 2026.
Building units (GLA London Building Stock Model): Contains public sector information licensed under the Open Government Licence v3.0 (Greater London Authority / UCL Bartlett Energy Institute and CASA). Contains OS data (c) Crown copyright and database right, published under the Ordnance Survey presumption to publish.
Energy performance certificates (MHCLG register): Energy Performance of Buildings Data England and Wales (c) Crown copyright.
Listed buildings (Historic England): © Historic England 2026. Contains Ordnance Survey data © Crown copyright and database right 2026. The Historic England GIS Data contained in this material was obtained on 12 September 2026. The most publicly available up to date Historic England GIS Data can be obtained from HistoricEngland.org.uk. Licensed under the Open Government Licence v.3.0.
Conservation areas (GLA London Datastore): Contains public sector information licensed under the Open Government Licence v3.0.
Method note
Every rating here is certified: the most recently lodged energy performance certificate for each address. Modelled ratings, the GLA’s 2017 estimates for buildings without a certificate, are never averaged in; where a population relies on them they are counted separately. Figures come from read-only queries run on 22 and 23 October 2026. Counts that could identify a building are merged or left out, and no addresses or owner names are published.
- Domestic archetype membership uses facts lodged on each address's latest certificate (property type, built form, age band), so domestic archetype counts are certified addresses by construction and unit-level certified coverage cannot be computed for them. Unit-level coverage is given for heritage-defined populations (conservation-area and listed domestic units) and for non-domestic units.
- Certified means a lodged register certificate (RdSAP/SAP or CEPC). GLA 2017 aggregate rows and modelled (rvEPC) ratings are excluded from every distribution. Modelled ratings appear only as separate counts of units that rely on them.
- The unit of analysis for ratings is the address (UPRN): its most recently lodged certificate, with ties broken as the product does (lodged date, then record order). A stock-model 'unit' can be a whole block, so unit counts and address counts differ. 29.5% of London's latest domestic certificates are past 10 years from lodgement and may predate works since done.
- Numeric domestic recommendation codes are labelled with the register's own summary text, taken from certificates BuildGrade holds with both code and text. This assumes a code means the same across register versions. Code 7's current register text reads '50 mm internal or external wall insulation', and older certificates phrase it differently. Hot-water-cylinder codes 2 and 3 were left out of the top-measure lists.
- Recommendation rows are loaded for 79-97% of the latest domestic certificates and 97-99% of the latest non-domestic certificates, depending on lodgement year (some certificates carry no recommendations), so recommendation shares are lower bounds.
- Cost text is reported exactly as lodged and varies with register version (PV, for example, carries '£3,500 - £5,500', '£5,000 - £8,000' and '£9,000 - £14,000'), so the most common text and its share of rows is given. The texts are not current prices. Lighting cost text varies per certificate (most common share under 15%). Non-domestic recommendations carry a payback category (SHORT, MEDIUM, LONG, OTHER), not a £ cost.
- Heritage flags are spatial matches applied to the whole stock-model unit: listed means the centroid is within 5 m of an NHLE polygon or the footprint overlaps one by at least half; conservation area means the centroid is inside a GLA polygon. Every flat in a flagged block inherits the flag, so listed counts can be over or under. Listed matches: 10,294 domestic units by centroid and 5,551 by footprint.
- Tenure is as recorded at lodgement and may have changed since. Certificates with unknown or blank tenure are excluded from tenure shares (tenure-known share given per study). The MEES counts are screening counts, not compliance findings, and exemptions are not modelled.
- MEES status. Domestic: the E floor is law for private lets (since April 2020); band C by 2030 is confirmed policy, not yet law (government response 21 January 2026; needs legislation, and compliance is to be judged on reformed EPC metrics). Non-domestic: the E floor is law (since April 2023); the 2027 C milestone is not being taken forward, and B by 2030 was revised on 18 June 2026 to B from 2031 for buildings over 1,000 m², where cost-effective, which is not yet law. These are BuildGrade's recorded policy positions; check the current government position before relying on them.
- Wall descriptions marked 'as built ... (assumed)' are RdSAP defaults where the assessor could not verify the construction (for example 79.4% of 1930-1949 semis lodged as solid brick). Treat them as lodged descriptions, not survey findings.
- The potential rating on a certificate assumes every recommended measure is installed, including measures that may need planning permission or listed building consent, so 'potential C or better' is an upper bound on what is consentable.
- Consent statements (permitted development, conservation-area cladding, listed building consent, flats lacking householder rights) are general planning context for England, not legal advice, and are not computed from the database. Article 4 directions vary by borough and were not queried.
- London only: units outside the 33 London local authorities were not used. Other UK cities are in preparation; the Bristol and Cardiff pilots are not yet live.