EPC ratings explained: what bands A to G mean
Every Energy Performance Certificate carries a score from 1 to 100 and a letter from A to G. The letter gets the attention, but the score is what actually moves.
The bands and their scores
The score comes from the government’s Standard Assessment Procedure, which models what your home should cost to heat and light. The bands sit at fixed boundaries:
| Band | Score | What it usually means |
|---|---|---|
| A | 92-100 | Rare. New builds with solar panels and serious insulation. |
| B | 81-91 | Most new builds land here. |
| C | 69-80 | A well-insulated older home, or a decent flat. |
| D | 55-68 | The most common band for existing homes. |
| E | 39-54 | The legal minimum for rented homes. |
| F | 21-38 | Poorly insulated, usually older housing. |
| G | 1-20 | The coldest stock: think solid stone walls and no central heating. |
Why so many homes are D
Britain has old housing. A Victorian terrace with solid walls starts with a heavy handicap, and gas central heating plus loft insulation typically only carries it into the D range. New builds, by contrast, land on B almost by default.
That split shows in the numbers. Across England and Wales, 64.5% of certificates lodged in the last 4 quarters were C or better. That figure leans towards new builds and recently improved homes, because certificates are only lodged when a home is built, sold or let. The stock as a whole rates worse than the recent lodgements do. You can see how your area compares on our local authority table.
The two ratings on your certificate
Your EPC shows a current rating and a potential rating. The potential is what the assessor calculates you would score if you carried out the recommended improvements listed on the certificate. A home showing “currently E, potential B” has a lot of cheap wins left. One showing “currently D, potential D” has probably done the easy things already.
What the score is actually measuring
The assessment models running costs, so it rewards insulation, efficient heating and low-energy lighting. It is a model of the building, and never a measurement of your bills: your actual usage, tariff and thermostat habits sit outside it. The assessment method for existing homes was updated in June 2025, so a certificate issued since then may score slightly differently from an older one for the same house.
What to do with a low rating
Start with the recommendations list on your own certificate; it is ordered and costed for your actual house. Then read how to improve your EPC rating for what each measure typically costs and which ones move the score most.