EPC rating and sold prices in SN3 (Swindon)
In postcode district SN3 (Swindon), homes rated EPC C or better sold for 6% more per square metre than D–G homes (median £3,042 vs £2,871, 9,516 sales). Like for like — same size, type, build period and year — the difference is −0.1% (95% range −1.1% to +0.8%): the EPC band itself is not reflected in sale prices here. 0 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 85 m² against 85 m² for D–G; the most common build period is 2012 onwards for C+ and 1950–1966 for D–G; 56% of C+ and 63% of D–G sales are detached or semi-detached houses.
| Comparing C+ with D–G homes… | Difference | 95% range |
|---|---|---|
| Raw gap per m² (medians) | +6% | — |
| Whole price, nothing held equal | +4.4% | +2.8% to +6.0% |
| Same floor area | +4.5% | +3.4% to +5.7% |
| + same property type | +7.5% | +6.5% to +8.5% |
| + same build period | +3.3% | +2.1% to +4.5% |
| + same year of sale | −0.1% | −1.1% to +0.8% |
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 SN3
| Sector | Sales | Raw gap | Like-for-like | 95% range |
|---|---|---|---|---|
| SN3 1 | 1,782 | −6% | −1.1% | −3.1% to +1.1% |
| SN3 2 | 926 | +8% | +1.8% | −0.4% to +4.0% |
| SN3 3 | 1,182 | +17% | +1.7% | −0.7% to +4.1% |
| SN3 4 | 2,565 | +4% | +1.5% | −0.1% to +3.1% |
| SN3 5 | 868 | +10% | +0.8% | −1.1% to +2.6% |
| SN3 6 | 2,111 | +15% | +0.8% | −1.3% to +2.9% |
▲ 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 SN3
| EPC band (last certificate before sale) | Sales | Median £ per m² |
|---|---|---|
| A | 134 | £3,542 |
| B | 2,083 | £3,176 |
| C | 2,916 | £2,869 |
| D | 3,549 | £2,905 |
| E | 731 | £2,750 |
| F | 87 | £2,606 |
| G | 16 | £2,128 |
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.