Does a C-or-better EPC sell for more in LL40 1 (Gwynedd)?
Too few comparable sales here for a reliable like-for-like figure. In postcode sector LL40 1 (Gwynedd), comparing like with like — same floor area, property type, build period and year of sale — there are too few comparable sales in each group for a reliable figure; for district LL40 as a whole the like-for-like difference is +9.4% (95% range +2.1% to +17.3%). The raw gap is bigger: C+ homes sold for 16% more per square metre than D–G homes (median £2,050 vs £1,762, 369 sales 2015–2026), mostly because they are different homes. Across England and Wales the like-for-like figure is +1.2%. Data: HM Land Registry Price Paid to 30 September 2026 matched to the EPC register.
From the raw gap to like-for-like
The homes are not alike: C+ homes here have a median floor area of 94 m² against 84 m² for D–G; the most common build period is 2003–2006 for C+ and before 1900 for D–G; 69% of C+ and 40% of D–G sales are detached or semi-detached houses.
This sector has fewer than 150 matched sales, fewer than 30 in one group, or an estimate too imprecise or implausibly large to trust, so the like-for-like comparison is not shown; the district figure is above.
Sold prices by EPC band in LL40 1
| EPC band (last certificate before sale) | Sales | Median £ per m² |
|---|---|---|
| B | 11 | £2,708 |
| C | 80 | £1,987 |
| D | 116 | £1,789 |
| E | 90 | £1,706 |
| F | 47 | £1,716 |
| G | 25 | £1,750 |
A median is shown when a band has at least 10 sales.
C or better vs D–G, by property type
| Type | C+ sales | C+ £/m² | D–G sales | D–G £/m² |
|---|---|---|---|---|
| Detached | 41 | £2,181 | 54 | £2,122 |
| Semi-detached | 22 | £2,146 | 58 | £1,860 |
| Terraced | 19 | £1,824 | 154 | £1,688 |
| Flat / maisonette | 9 | — | 12 | £1,543 |
Compared with the wider area
| Area | Sales | Like-for-like | 95% range |
|---|---|---|---|
| Sector LL40 1 | 369 | too few | — |
| District LL40 | 593 | +9.4% | +2.1% to +17.3% |
| England and Wales | 1,000,000 (sample) | +1.2% | +0.9% to +1.5% |
Average gas use in LL40 1 (2024): meters vs certificates
A rough comparison: the certificate figure is an upper-bound estimate (primary energy including lighting, converted with one factor), so treat the share as an order of magnitude.
| Postcodes with published gas data (5+ meters) | 70 (807 meters) |
|---|---|
| Median gas use per meter (median of postcodes) | 8,176 kWh |
| Gas-heated homes with an EPC | 609 |
| Energy implied by their certificates (median) | 17,119 kWh |
| Metered gas as a share of the certificate figure (median of 61 postcodes) | 47% (middle half 39%–55%) |
Certificates by band imply: B 6,488 kWh (17 homes) · C 12,013 kWh (228 homes) · D 19,988 kWh (244 homes) · E 30,991 kWh (97 homes) · F 53,441 kWh (11 homes). Across England and Wales, real use is much closer to the certificate for A–C homes than for D–G homes, so the saving an upgrade promises is usually smaller than the certificate suggests.
Certificate energy = primary energy per m² × floor area ÷ 1.13, for homes whose latest certificate shows mains gas heating; it also covers lighting and other uses, so it is an upper bound for gas. DESNZ gas is weather-corrected and covers all meters in the postcode, with or without a certificate.
369 of 471 house and flat sales in the sector since 2015 (78%) were matched to a certificate.
How this is calculated
- Every standard sale (HM Land Registry Price Paid, category A) since January 2015 is matched to the latest energy certificate of the same address (postcode + house number or name + flat) lodged from 10 years before to 3 months after the sale; sales with no certificate or an ambiguous match are left out. Across England and Wales 92% of sales match.
- Price per m² uses the certificate's total floor area (15–1,000 m²).
- Like-for-like premium: regression of the log of price on “C or better”, log floor area, property type, the certificate's build period and the year of sale. The 95% range shows how precise the estimate is; when it includes zero, the data cannot tell the premium apart from none.
Caveats
- The band is the one on the certificate before the sale; certificates are a median 0.8 years old at the sale, but a quarter are over 4 years old and some homes were improved since.
- Condition, garden, parking, views and the exact position within the sector are not known; a premium could hide in them, or they could hide one.
- Individual sales and addresses are not shown.