EPC rating and sold prices in NP15 (Monmouthshire)
In postcode district NP15 (Monmouthshire), homes rated EPC C or better sold for 3% more per square metre than D–G homes (median £3,009 vs £2,928, 1,004 sales). Like for like — same size, type, build period and year — homes rated C or better sold for 4.2% less (95% range −7.5% to −0.8%). 1 of 2 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 98 m² against 109 m² for D–G; the most common build period is 2007–2011 for C+ and before 1900 for D–G; 66% of C+ and 80% of D–G sales are detached or semi-detached houses.
| Comparing C+ with D–G homes… | Difference | 95% range |
|---|---|---|
| Raw gap per m² (medians) | +3% | — |
| Whole price, nothing held equal | −12.2% | −18.3% to −5.7% |
| Same floor area | −0.4% | −4.0% to +3.4% |
| + same property type | +2.3% | −1.1% to +5.9% |
| + same build period | −0.4% | −4.7% to +4.0% |
| + same year of sale | −4.2% | −7.5% 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 NP15
| Sector | Sales | Raw gap | Like-for-like | 95% range |
|---|---|---|---|---|
| NP15 1 | 786 | +3% | −4.2% ▼ | −8.0% to −0.2% |
| NP15 2 | 218 | +6% | −3.6% | −10.0% to +3.3% |
▲ 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 NP15
| EPC band (last certificate before sale) | Sales | Median £ per m² |
|---|---|---|
| A | 2 | too few |
| B | 50 | £3,213 |
| C | 302 | £2,981 |
| D | 409 | £2,904 |
| E | 174 | £2,971 |
| F | 54 | £2,623 |
| G | 13 | £2,894 |
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.