EPC rating and sold prices in SO15 (Southampton)
In postcode district SO15 (Southampton), homes rated EPC C or better sold for 5% more per square metre than D–G homes (median £3,025 vs £2,875, 6,169 sales). Like for like — same size, type, build period and year — homes rated C or better sold for 1.8% more (95% range +0.7% to +2.9%). 1 of 8 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 70 m² against 88 m² for D–G; both groups are most often built in 1900–1929; 21% of C+ and 51% of D–G sales are detached or semi-detached houses.
| Comparing C+ with D–G homes… | Difference | 95% range |
|---|---|---|
| Raw gap per m² (medians) | +5% | — |
| Whole price, nothing held equal | −13.1% | −15.1% to −11.0% |
| Same floor area | +3.6% | +2.3% to +4.9% |
| + same property type | +10.2% | +8.9% to +11.5% |
| + same build period | +3.8% | +2.5% to +5.0% |
| + same year of sale | +1.8% | +0.7% to +2.9% |
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 SO15
| Sector | Sales | Raw gap | Like-for-like | 95% range |
|---|---|---|---|---|
| SO15 0 | 248 | +11% | +2.9% | −1.2% to +7.2% |
| SO15 1 | 291 | +15% | +3.9% | −1.4% to +9.5% |
| SO15 2 | 1,555 | +11% | +1.3% | −1.2% to +3.9% |
| SO15 3 | 1,049 | +6% | +1.4% | −0.8% to +3.8% |
| SO15 4 | 475 | +3% | +0.5% | −2.1% to +3.2% |
| SO15 5 | 1,616 | +3% | +2.9% ▲ | +0.9% to +5.0% |
| SO15 7 | 429 | +2% | +1.2% | −1.8% to +4.3% |
| SO15 8 | 506 | +8% | +1.6% | −1.1% to +4.3% |
▲ 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 SO15
| EPC band (last certificate before sale) | Sales | Median £ per m² |
|---|---|---|
| B | 586 | £3,171 |
| C | 1,931 | £2,972 |
| D | 2,705 | £2,941 |
| E | 775 | £2,750 |
| F | 130 | £2,503 |
| G | 42 | £2,282 |
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.