EPC rating and sold prices in SA20 (Carmarthenshire)
In postcode district SA20 (Carmarthenshire), homes rated EPC C or better sold for 8% less per square metre than D–G homes (median £1,687 vs £1,843, 405 sales). Like for like — same size, type, build period and year — the difference is +0.9% (95% range −6.9% to +9.4%): the EPC band itself is not reflected in sale prices here. 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 103 m² against 105 m² for D–G; both groups are most often built before 1900; 72% of C+ and 68% of D–G sales are detached or semi-detached houses.
| Comparing C+ with D–G homes… | Difference | 95% range |
|---|---|---|
| Raw gap per m² (medians) | −8% | — |
| Whole price, nothing held equal | −0.7% | −15.1% to +16.1% |
| Same floor area | −5.7% | −15.9% to +5.7% |
| + same property type | −1.8% | −11.6% to +9.1% |
| + same build period | +0.7% | −8.8% to +11.2% |
| + same year of sale | +0.9% | −6.9% to +9.4% |
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 SA20
| Sector | Sales | Raw gap | Like-for-like | 95% range |
|---|---|---|---|---|
| SA20 0 | 405 | −8% | 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 SA20
| EPC band (last certificate before sale) | Sales | Median £ per m² |
|---|---|---|
| B | 4 | too few |
| C | 42 | £1,673 |
| D | 167 | £1,655 |
| E | 111 | £1,938 |
| F | 58 | £2,025 |
| G | 23 | £2,200 |
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.