Only 35.0% of Swansea homes with a current energy performance certificate (EPC) hold a C rating or better. That is the lowest share of the three South Wales cities: Cardiff is at 42.2% and Newport at 47.4%. Within Swansea, price is a poor guide to energy efficiency. The greenest district sits mid-table on price, and the dearest district has one of the weakest rating profiles in the city.
The figures come from HM Land Registry sales and the EPC register, fetched on 4 October 2026.
How the figures are built
Each home is counted once, using its most recent EPC certificate, so a home certified twice is not counted twice. Price medians use 2025 HM Land Registry sales in category A (detached, semi-detached, terraced and flats). A district appears in the EPC table only if it has at least 200 current certificates, and in the price table only if it has at least 30 sales.
EPC bands are modelled estimates of a building's energy performance, based on its fabric, heating and construction. They are not metered bills, so a band describes the building, not what a household spends.
Citywide: the lowest of the three
| City | Homes with a current EPC | Rated C or better | Rated F or G | 2025 median sale price |
|---|---|---|---|---|
| Swansea | 43,732 | 35.0% | 3.6% | £209,000 (3,021 sales) |
| Cardiff | 64,133 | 42.2% | 1.7% | £270,000 (4,574 sales) |
| Newport | 30,136 | 47.4% | 1.7% | £240,000 (2,328 sales) |
Swansea also has more than twice the share of homes in the two weakest bands (3.6%, against 1.7% in both other cities). The pattern across the three cities is not consistent either. Swansea is the cheapest and the coldest. Cardiff, the dearest, sits between the two. Newport, the middle-priced city, has the greenest stock.
The district ladder
Swansea's districts, ordered by 2025 median sale price:
| District | 2025 median price | Sales | Rated C or better | Rated F or G | Built before 1950 |
|---|---|---|---|---|---|
| SA1 (city centre and docks) | £145,000 | 518 | 37.7% | 2.2% | 68.0% |
| SA5 | £158,500 | 353 | 28.2% | 3.5% | 52.1% |
| SA6 | £179,000 | 382 | 30.0% | 3.6% | 44.1% |
| SA7 | £190,000 | 176 | 52.1% | 1.8% | 21.2% |
| SA4 | £230,000 | 662 | 44.0% | 3.4% | 35.7% |
| SA2 (Sketty and Uplands) | £270,500 | 498 | 27.4% | 3.2% | 46.6% |
| SA3 (Gower coast) | £370,000 | 425 | 29.3% | 7.3% | 32.7% |
"Built before 1950" is the share of rated certificates with a pre-1950 construction period. Certificates with no recorded construction period are excluded from that column.
The cheapest district, SA1, rates above the city average at 37.7%. SA7 is the fourth-cheapest district and has the highest share of C-or-better homes, at 52.1%. SA2, at £270,500, has the lowest share in the city, at 27.4%. SA3, the dearest district at £370,000, has 29.3% rated C or better and the highest F-or-G share in the city, at 7.3%.
Across the seven districts, the rank correlation between median price and the C-or-better share is −0.21. That is a weak negative link: if anything, the dearer districts rate slightly worse. Seven districts is too few to show a trend, and this table does not establish one.
Build era explains much of the gap
Across Swansea certificates with a recorded construction period, the era of the building tracks its rating closely:
| Construction period | Rated certificates | Rated C or better |
|---|---|---|
| Before 1900 | 4,771 | 11.5% |
| 1900–1929 | 9,381 | 15.0% |
| 1930–1949 | 4,470 | 16.6% |
| 1950–1966 | 5,903 | 22.9% |
| 1967–1975 | 5,422 | 22.9% |
| 1976–1990 | 4,179 | 49.3% |
| 1991–2002 | 3,547 | 58.7% |
| 2003 onwards | 3,475 | 96.8% |
Overall, 45% of Swansea certificates with a recorded construction period are for homes built before 1950. The era pattern accounts for much of the district ladder. SA7 has the lowest pre-1950 share (21.2%) and the highest C-or-better share. SA2 has nearly half its certificates for pre-1950 homes (46.6%) and rates at 27.4%.
Era does not explain everything. SA1 has the oldest stock by this measure (68.0% pre-1950) yet rates better than SA2 and SA5. The data in this article do not show why.
The SA3 cold tail
SA3 is the one district where age does not account for the result. Its pre-1950 share is 32.7%, lower than SA2's, yet its F-or-G share of 7.3% is twice the citywide figure. Splitting SA3 by postcode sector shows the weakness is concentrated. The sector SA3 1 (552 rated certificates) has 18.5% rated C or better and 24.3% rated F or G. The other SA3 sectors sit between 27.5% and 33.5% C-or-better.
Homecost's extract of the register does not include heating type or gas-grid connection, so the cause of the SA3 1 result is not tested here.
What the figures do not show
- Coverage. Homecost's Swansea address table holds 64,264 addresses, and 43,732 of them (68%) match a current certificate. Homes without a certificate are not in these shares.
- Certificate age. The latest certificate for a home can be several years old. These shares describe the register as it stands, not the present condition of every home.
- Prices. Medians describe recorded sales in each district. They are not valuations of any property.
Try the tool
Enter SA2 0QS in the Homecost postcode tool to see the True Cost view for homes on that postcode, or browse the regional price guides for other parts of the country.
Related reading: Sketty and Uplands house prices in SA2, the Gower coast premium in SA3, South Wales buy-versus-run costs, Bristol's EPC ratings by postcode, and EPC ratings explained. Homes in Wales pay Land Transaction Tax rather than stamp duty, and the SDLT and LTT crossover shows where the two regimes meet.
Based on 3,021 HM Land Registry sales (2025, category A) and 43,732 current EPC certificates for Swansea. Figures fetched 4 October 2026. See our guides for the method behind each figure.