EPC rating and sold prices in NP24 (Caerphilly)
In postcode district NP24 (Caerphilly), homes rated EPC C or better sold for 35% more per square metre than D–G homes (median £1,243 vs £918, 592 sales). Like for like — same size, type, build period and year — homes rated C or better sold for 8.7% more (95% range +1.2% to +16.8%). Data: HM Land Registry to 30 September 2026, EPC register.
From the raw gap to like-for-like
The homes are not alike: C+ homes here have a median floor area of 87 m² against 79 m² for D–G; both groups are most often built in 1900–1929; 22% of C+ and 8% of D–G sales are detached or semi-detached houses.
| Comparing C+ with D–G homes… | Difference | 95% range |
|---|---|---|
| Raw gap per m² (medians) | +35% | — |
| Whole price, nothing held equal | +47.3% | +32.0% to +64.4% |
| Same floor area | +34.2% | +22.3% to +47.3% |
| + same property type | +25.5% | +16.1% to +35.7% |
| + same build period | +22.2% | +12.6% to +32.6% |
| + same year of sale | +8.7% | +1.2% to +16.8% |
The first row compares median prices per m²; the second compares whole prices; each later row adds one more thing that must be equal, ending with the like-for-like premium (regression of log price; build period from the certificate, 12 bands). The raw gap per m² and the whole-price gap differ because C+ and D–G homes differ in size.
Postcode sectors in NP24
| Sector | Sales | Raw gap | Like-for-like | 95% range |
|---|---|---|---|---|
| NP24 6 | 592 | +35% | too few | — |
▲ green: premium distinguishable from zero; ▼ red: discount; plain: no measurable difference. Small areas have fewer sales, so their 95% ranges are wider.
Sold prices by EPC band in NP24
| EPC band (last certificate before sale) | Sales | Median £ per m² |
|---|---|---|
| B | 1 | too few |
| C | 88 | £1,246 |
| D | 347 | £939 |
| E | 128 | £863 |
| F | 26 | £748 |
| G | 2 | too few |
A median is shown when a band has at least 10 sales.
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.