EPC rating and sold prices in TW18 (Spelthorne)
In postcode district TW18 (Spelthorne), homes rated EPC C or better sold for 2% more per square metre than D–G homes (median £5,098 vs £4,982, 4,434 sales). Like for like — same size, type, build period and year — the difference is −0.4% (95% range −1.6% to +0.8%): the EPC band itself is not reflected in sale prices here. 0 of 4 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 72 m² against 84 m² for D–G; the most common build period is 2012 onwards for C+ and 1930–1949 for D–G; 26% of C+ and 61% of D–G sales are detached or semi-detached houses.
| Comparing C+ with D–G homes… | Difference | 95% range |
|---|---|---|
| Raw gap per m² (medians) | +2% | — |
| Whole price, nothing held equal | −9.8% | −12.0% to −7.6% |
| Same floor area | −1.3% | −2.6% to 0.0% |
| + same property type | +4.2% | +2.9% to +5.5% |
| + same build period | +1.1% | −0.1% to +2.4% |
| + same year of sale | −0.4% | −1.6% 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 TW18
| Sector | Sales | Raw gap | Like-for-like | 95% range |
|---|---|---|---|---|
| TW18 1 | 1,213 | −3% | +0.3% | −1.5% to +2.3% |
| TW18 2 | 1,317 | −4% | −0.2% | −2.3% to +1.9% |
| TW18 3 | 741 | −2% | −3.2% | −7.6% to +1.5% |
| TW18 4 | 1,163 | +18% | +0.2% | −2.0% to +2.5% |
▲ 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 TW18
| EPC band (last certificate before sale) | Sales | Median £ per m² |
|---|---|---|
| A | 3 | too few |
| B | 361 | £5,943 |
| C | 1,290 | £4,925 |
| D | 1,956 | £5,000 |
| E | 710 | £4,884 |
| F | 88 | £4,978 |
| G | 26 | £4,810 |
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.