How do you read an EPC certificate?
An EPC shows a current and a potential rating, the SAP score behind each, estimated annual running costs, and a table of recommended improvements with indicative costs and savings. The potential figure assumes every recommendation is carried out, so treat it as a ceiling rather than a forecast.
- The left figure is current; the right is potential after all works.
- Running costs are modelled on standard occupancy, not your bills.
- Recommendations are generic and are not ordered by value for money.
- The property reference number identifies the lodged certificate.
The two ratings
Every EPC shows two figures side by side. The left-hand one is the current rating: what the property scores as it stands today. The right-hand one is the potential rating: what it would score if every single recommendation on the certificate were carried out.
The potential figure is routinely misread. It is not a forecast, and it is not a target anyone expects you to hit. It assumes the full list is completed, including measures that may be unconsentable on your building. Treat it as a ceiling.
| Band | SAP score | What it means |
|---|---|---|
| A | 92–100 | Excellent — very low running costs |
| B | 81–91 | Very good — efficient modern home |
| C | 69–80 | Good — the target for rented homes by 2030 |
| D | 55–68 | Average — where most of Rugby sits |
| E | 39–54 | Below par — today’s legal minimum to let |
| F–G | 1–38 | Poor — cannot be let without works or an exemption |
The running-cost estimates
The certificate carries estimated annual costs for heating, hot water and lighting. These are modelled on a standard household — a fixed occupancy pattern, fixed temperatures, fixed hours. They are there so two buildings can be compared, not so you can predict your own bills. A household that heats one room will spend less; one with the heating on constantly will spend more.
The recommendations table
Each recommended measure comes with an indicative cost, a typical annual saving and the band it would help reach. Three things are worth knowing:
- The costs are national averages, not quotes for your property.
- The list is not ordered by value for money — a cheap measure and an expensive one sit side by side.
- The software does not know what your building can obtain consent for.
That is why we re-rank them by cost per SAP point through our MEES consultancy rather than working down the certificate in order.
The reference number
Every lodged certificate has a Report Reference Number. Quote it when a solicitor, agent or lender asks for the EPC, and use it to find the certificate again on the government's Find an energy certificate service.
Next steps
If your certificate looks worse than the property deserves, it is usually an evidence problem rather than a building problem. Book a fresh domestic EPC with the paperwork ready, or get a quote.
Looking for your own area? We have local EPC guides for Rugby town centre, Hillmorton, Newbold on Avon, Overslade, Brownsover, Bilton, Brinklow and every other Rugby area.