EPC rating and sold prices in CF10 (Cardiff)
In postcode district CF10 (Cardiff), homes rated EPC C or better sold for 3% more per square metre than D–G homes (median £2,517 vs £2,441, 2,833 sales). Like for like — same size, type, build period and year — homes rated C or better sold for 3.3% less (95% range −5.5% to −0.9%). 1 of 3 sectors with enough sales show a difference distinguishable from zero. 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 67 m² against 76 m² for D–G; both groups are most often built in 2003–2006; 2% of C+ and 6% of D–G sales are detached or semi-detached houses.
| Comparing C+ with D–G homes… | Difference | 95% range |
|---|---|---|
| Raw gap per m² (medians) | +3% | — |
| Whole price, nothing held equal | −6.8% | −10.0% to −3.5% |
| Same floor area | +1.0% | −1.3% to +3.5% |
| + same property type | +3.8% | +1.4% to +6.2% |
| + same build period | −1.7% | −4.1% to +0.7% |
| + same year of sale | −3.3% | −5.5% to −0.9% |
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 CF10
| Sector | Sales | Raw gap | Like-for-like | 95% range |
|---|---|---|---|---|
| CF10 1 | 202 | +44% | too few | — |
| CF10 2 | 279 | +5% | −3.0% | −8.7% to +3.0% |
| CF10 3 | 65 | +21% | too few | — |
| CF10 4 | 1,092 | 0% | −1.8% | −4.7% to +1.2% |
| CF10 5 | 1,195 | −1% | −5.0% ▼ | −8.9% to −0.9% |
▲ 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 CF10
| EPC band (last certificate before sale) | Sales | Median £ per m² |
|---|---|---|
| B | 856 | £2,613 |
| C | 1,405 | £2,460 |
| D | 459 | £2,485 |
| E | 104 | £2,370 |
| F | 7 | too few |
| 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.