EPC rating and sold prices in SA1 (Swansea)
In postcode district SA1 (Swansea), homes rated EPC C or better sold for 57% more per square metre than D–G homes (median £2,069 vs £1,314, 6,181 sales). Like for like — same size, type, build period and year — the difference is −0.5% (95% range −2.8% to +2.0%): the EPC band itself is not reflected in sale prices here. 3 of 6 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 71 m² against 85 m² for D–G; the most common build period is 2012 onwards for C+ and 1900–1929 for D–G; 21% of C+ and 21% of D–G sales are detached or semi-detached houses.
| Comparing C+ with D–G homes… | Difference | 95% range |
|---|---|---|
| Raw gap per m² (medians) | +57% | — |
| Whole price, nothing held equal | +26.3% | +23.7% to +29.0% |
| Same floor area | +44.6% | +42.0% to +47.1% |
| + same property type | +35.5% | +32.9% to +38.1% |
| + same build period | +5.0% | +2.4% to +7.8% |
| + same year of sale | −0.5% | −2.8% to +2.0% |
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 SA1
| Sector | Sales | Raw gap | Like-for-like | 95% range |
|---|---|---|---|---|
| SA1 1 | 633 | +2% | −2.7% | −7.2% to +2.0% |
| SA1 2 | 781 | +67% | +5.4% ▲ | +0.5% to +10.5% |
| SA1 3 | 544 | +49% | +5.4% ▲ | +0.1% to +11.0% |
| SA1 4 | 422 | +8% | too few | — |
| SA1 6 | 1,409 | +48% | +2.2% | −1.9% to +6.5% |
| SA1 7 | 1,145 | +46% | +1.4% | −3.3% to +6.4% |
| SA1 8 | 1,222 | +64% | −8.3% ▼ | −15.2% 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 SA1
| EPC band (last certificate before sale) | Sales | Median £ per m² |
|---|---|---|
| A | 1 | too few |
| B | 1,113 | £2,115 |
| C | 1,451 | £2,000 |
| D | 2,376 | £1,405 |
| E | 1,051 | £1,182 |
| F | 153 | £1,000 |
| G | 36 | £936 |
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.