EPC rating and sold prices in SO18 (Southampton)
In postcode district SO18 (Southampton), homes rated EPC C or better sold for 1% less per square metre than D–G homes (median £3,067 vs £3,093, 5,899 sales). Like for like — same size, type, build period and year — homes rated C or better sold for 1.3% more (95% range +0.2% to +2.3%). 2 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 82 m² for D–G; the most common build period is 1983–1990 for C+ and 1930–1949 for D–G; 35% of C+ and 67% of D–G sales are detached or semi-detached houses.
| Comparing C+ with D–G homes… | Difference | 95% range |
|---|---|---|
| Raw gap per m² (medians) | −1% | — |
| Whole price, nothing held equal | −11.5% | −13.5% to −9.5% |
| Same floor area | −2.6% | −4.0% to −1.2% |
| + same property type | +8.6% | +7.3% to +9.9% |
| + same build period | +4.3% | +3.0% to +5.7% |
| + same year of sale | +1.3% | +0.2% to +2.3% |
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 SO18
| Sector | Sales | Raw gap | Like-for-like | 95% range |
|---|---|---|---|---|
| SO18 1 | 1,428 | −1% | +0.8% | −2.1% to +3.9% |
| SO18 2 | 1,169 | −3% | +3.6% ▲ | +1.5% to +5.8% |
| SO18 3 | 907 | 0% | +0.9% | −0.8% to +2.7% |
| SO18 4 | 636 | +3% | +3.9% ▲ | +0.7% to +7.1% |
| SO18 5 | 1,205 | −4% | +1.6% | −0.4% to +3.7% |
| SO18 6 | 554 | −10% | −2.8% | −6.4% to +1.0% |
▲ 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 SO18
| EPC band (last certificate before sale) | Sales | Median £ per m² |
|---|---|---|
| A | 5 | too few |
| B | 468 | £2,928 |
| C | 1,866 | £3,094 |
| D | 2,795 | £3,155 |
| E | 641 | £2,935 |
| F | 102 | £2,770 |
| G | 22 | £2,694 |
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.