Five outer London boroughs sit at the top of the capital's flat energy-performance-certificate coverage table: Enfield (48.5%), Bexley (46.4%), Hillingdon (45.0%), and Redbridge and Barking and Dagenham (both 41.2%). Each has roughly double the EPC match rate of London's weakest boroughs. The obvious explanation is that these are the boroughs with the biggest recent new-build booms — Barking Riverside, outer Enfield and Bexley estates, Hillingdon's Hayes and West Drayton schemes — and new flats should mean fresh certificates. Splitting the same 92,128 flats by whether they were ever sold as new build shows the opposite. In every one of the five boroughs, new-build flats are matched to a certificate far less often than the borough's older resale flats. These boroughs lead London despite their new-build stock, not because of it.
The coverage league table
The ranking below (HM Land Registry transactions joined to the EPC Open Data register, fetched 25 October 2026) is the subset of London's wider 33-borough table covered in the full London EPC-coverage comparison.
| Borough | Flat EPC coverage | 2025 median flat price | Flats tracked |
|---|---|---|---|
| Enfield | 48.5% | £330,000 | 26,533 |
| Bexley | 46.4% | £265,000 | 14,187 |
| Hillingdon | 45.0% | £315,000 | 21,214 |
| Redbridge | 41.2% | £317,000 | 20,005 |
| Barking and Dagenham | 41.2% | £240,000 | 10,189 |
Splitting the stock: new build versus resale
Flagging each flat address by whether a Land Registry record ever shows a new-build sale, then checking EPC-register coverage separately for each group, produces a consistent reversal across all five boroughs.
| Borough | New build share of flat stock | New-build flat coverage | Resale flat coverage |
|---|---|---|---|
| Barking and Dagenham | 47.9% | 17.5% | 63.0% |
| Hillingdon | 35.0% | 10.6% | 63.6% |
| Redbridge | 28.8% | 20.4% | 49.6% |
| Bexley | 26.3% | 24.5% | 54.2% |
| Enfield | 21.8% | 29.7% | 53.7% |
Resale flats clear 49–64% coverage in every borough. New-build flats never reach 30%, and in Hillingdon and Barking and Dagenham — the two boroughs with the heaviest new-build shares — new-build coverage is the lowest of the five at 10.6% and 17.5% respectively. The boroughs with the biggest new-build pipelines are the ones where new build drags the average down hardest; their overall lead comes entirely from how well-matched their much larger resale stock already is.
A later sale, not just time, seems to trigger the match
This is the same pattern first identified in Tower Hamlets' new-build flats, where coverage tripled once a flat changed hands again after its original new-build sale. It holds across all five boroughs tested here too.
| Borough | Never resold since new build | Resold at least once since |
|---|---|---|
| Hillingdon | 6.4% | 19.8% |
| Barking and Dagenham | 6.9% | 33.1% |
| Bexley | 12.6% | 38.9% |
| Redbridge | 15.3% | 25.4% |
| Enfield | 18.3% | 37.9% |
A new-build flat that has never changed hands since its original sale is the least likely of any group to show up against a live EPC — as low as 6.4% in Hillingdon. One that has been resold at least once climbs to 20–39%, still short of the resale-stock baseline above but clearly closer to it. The most likely explanation is a matching problem rather than a compliance one: a certificate is typically logged at the point of marketing or completion, and large modern blocks with many similar flat-number addresses appear to be harder to reconcile between the Land Registry and EPC registers than older, more individually distinct properties.
IG11 7PS in Barking — a leasehold block on Arboretum Place with dozens of flats sold between 2008 and 2016 — illustrates the gap directly: several of its flats carry no energy rating on Homecost's register despite having changed hands more than once. That does not mean the building was ever marketed without a valid certificate — only that this particular address record hasn't matched to one. Anyone checking a specific flat should look it up directly rather than assume borough-wide coverage tells them anything about one address.
What this means for anyone checking a specific flat
A borough-wide EPC coverage figure is a useful guide to how complete the data is locally, not a guide to any single flat's actual energy rating. A newer block in a high-coverage borough can still come back with no matched certificate, while an older resale flat in the same postcode is more likely to show one. The only reliable check is the address itself — search a postcode on Homecost to see whether a specific flat's EPC has matched, rather than reading across from the borough average.
This analysis draws on 92,128 Land Registry flat records across the five boroughs, cross-referenced against the EPC Open Data register (fetched 25 October 2026). More EPC and cost-intelligence findings like this are collected in Homecost's cost intelligence guides.