Does a C-or-better EPC sell for more in NN17 1 (North Northamptonshire)?
A small premium for a better EPC here. In postcode sector NN17 1 (North Northamptonshire), comparing like with like — same floor area, property type, build period and year of sale — homes rated C or better sold for 3.1% more (95% range +0.6% to +5.6%). The raw gap is bigger: C+ homes sold for 10% more per square metre than D–G homes (median £2,370 vs £2,149, 1,309 sales 2015–2026), mostly because they are different homes. Across England and Wales the like-for-like figure is +1.2%. Data: HM Land Registry Price Paid to 30 September 2026 matched to the EPC register.
From the raw gap to like-for-like
The homes are not alike: C+ homes here have a median floor area of 77 m² against 77 m² for D–G; the most common build period is 2012 onwards for C+ and 1930–1949 for D–G; 41% of C+ and 58% of D–G sales are detached or semi-detached houses.
| Comparing C+ with D–G homes… | Difference | 95% range |
|---|---|---|
| Raw gap per m² (medians) | +10% | — |
| Whole price, nothing held equal | +12.2% | +7.6% to +16.9% |
| Same floor area | +10.3% | +6.8% to +14.0% |
| + same property type | +17.7% | +14.2% to +21.3% |
| + same build period | +13.8% | +9.9% to +17.8% |
| + same year of sale | +3.1% | +0.6% to +5.6% |
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.
Sold prices by EPC band in NN17 1
| EPC band (last certificate before sale) | Sales | Median £ per m² |
|---|---|---|
| A | 5 | too few |
| B | 100 | £2,599 |
| C | 287 | £2,318 |
| D | 683 | £2,212 |
| E | 207 | £1,978 |
| F | 20 | £1,905 |
| G | 7 | too few |
A median is shown when a band has at least 10 sales.
C or better vs D–G, by property type
| Type | C+ sales | C+ £/m² | D–G sales | D–G £/m² |
|---|---|---|---|---|
| Detached | 46 | £2,659 | 89 | £2,418 |
| Semi-detached | 113 | £2,318 | 441 | £2,162 |
| Terraced | 135 | £2,297 | 338 | £2,129 |
| Flat / maisonette | 98 | £2,287 | 49 | £1,804 |
Compared with the wider area
| Area | Sales | Like-for-like | 95% range |
|---|---|---|---|
| Sector NN17 1 | 1,309 | +3.1% | +0.6% to +5.6% |
| District NN17 | 6,702 | +1.7% | +0.2% to +3.1% |
| England and Wales | 1,000,000 (sample) | +1.2% | +0.9% to +1.5% |
Average gas use in NN17 1 (2024): meters vs certificates
A rough comparison: the certificate figure is an upper-bound estimate (primary energy including lighting, converted with one factor), so treat the share as an order of magnitude.
| Postcodes with published gas data (5+ meters) | 179 (4,259 meters) |
|---|---|
| Median gas use per meter (median of postcodes) | 10,520 kWh |
| Gas-heated homes with an EPC | 2,862 |
| Energy implied by their certificates (median) | 15,802 kWh |
| Metered gas as a share of the certificate figure (median of 172 postcodes) | 64% (middle half 59%–71%) |
Certificates by band imply: B 6,370 kWh (221 homes) · C 11,919 kWh (1,002 homes) · D 17,988 kWh (1,314 homes) · E 26,149 kWh (301 homes) · F 34,302 kWh (15 homes). Across England and Wales, real use is much closer to the certificate for A–C homes than for D–G homes, so the saving an upgrade promises is usually smaller than the certificate suggests.
Certificate energy = primary energy per m² × floor area ÷ 1.13, for homes whose latest certificate shows mains gas heating; it also covers lighting and other uses, so it is an upper bound for gas. DESNZ gas is weather-corrected and covers all meters in the postcode, with or without a certificate.
1,309 of 1,386 house and flat sales in the sector since 2015 (94%) were matched to a certificate.
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.