The EPC A to G scale explained
Each band reflects energy efficiency measured on a 0 to 100 SAP (Standard Assessment Procedure) score.
| Band | SAP score | Typical annual energy cost (3-bed semi) | What it usually means |
|---|---|---|---|
| A | 92 to 100 | Under £800 | New-build or highly insulated home, heat pump or solar |
| B | 81 to 91 | £800 to £1,100 | Well-insulated, modern heating, double glazing throughout |
| C | 69 to 80 | £1,100 to £1,500 | Good efficiency, the level most policies target |
| D | 55 to 68 | £1,500 to £2,000 | Average, typical of much UK housing stock |
| E | 39 to 54 | £2,000 to £2,700 | Below average, higher bills, current minimum for letting |
| F | 21 to 38 | £2,700 to £3,500 | Poor, significant upgrade costs likely |
| G | 1 to 20 | Over £3,500 | Very poor, cannot legally be let without an exemption |
Cost figures are illustrative national averages based on typical energy prices as of 2026. Actual costs depend on property size, occupant behaviour and local energy tariffs.
Why the EPC matters when buying a property
The EPC gives you an at-a-glance picture of future running costs, which can be just as important as the purchase price when assessing affordability. A D-rated home might look attractive at £220,000 compared to a C-rated neighbour at £230,000, but if the D-rated home costs £500 more per year to heat and power, you will spend £10,000 extra in energy over 20 years, potentially more than the price difference.
The certificate also flags what work the property may need. Every EPC includes a recommendations section listing specific improvements, the indicative cost of each (for example, £1,000 to £2,000 for loft insulation), the estimated annual saving and the rating band you would achieve once improvements are made. This gives you a ready-made negotiation tool or a budgeting framework for upgrades after purchase.
Lenders are increasingly using EPC ratings to price mortgages. Several major banks offer 'green mortgages' with lower interest rates for homes rated A or B, and some apply higher stress tests or maximum LTV restrictions on poorly rated properties. The government has also signalled that minimum standards for owner-occupied properties may tighten in future, making the rating a longer-term consideration as well.
What an EPC certificate contains
- The current energy efficiency rating (A to G) and SAP score out of 100.
- The 'potential' rating and score achievable if all recommended improvements were made.
- Estimated current annual energy costs for heating, hot water and lighting.
- Estimated future annual costs after recommended improvements.
- The environmental impact (CO2 emissions) rating on the same A to G scale.
- A detailed recommendations table listing specific improvements, estimated costs and estimated annual savings.
- The name and accreditation number of the domestic energy assessor.
- The certificate's issue date and 10-year expiry date.
- A unique certificate reference number for verification on the government register.
Common improvements and their typical EPC impact
Upgrade costs and band improvements vary by property type and condition. These are indicative figures.
| Improvement | Typical cost | Estimated annual saving | Potential band improvement |
|---|---|---|---|
| Loft insulation (top up to 270mm) | £300 to £600 | £150 to £300 | One band |
| Cavity wall insulation | £500 to £1,500 | £150 to £350 | One band |
| Solid wall insulation (external) | £8,000 to £16,000 | £300 to £600 | One to two bands |
| Replace old boiler with A-rated condensing boiler | £2,000 to £4,000 | £200 to £400 | Half to one band |
| Air source heat pump | £8,000 to £15,000 (grants may apply) | Variable | One to two bands |
| Double glazing (replacing single) | £4,000 to £10,000 | £100 to £200 | Half a band |
| Solar PV panels (3.5kWp) | £5,000 to £8,000 | £300 to £600 | One to two bands |
| LED lighting throughout | £50 to £200 | £40 to £80 | Marginal |
Government schemes including the Great British Insulation Scheme and Boiler Upgrade Scheme may reduce costs. Check eligibility on GOV.UK.
How to get or update an EPC
Check whether a valid EPC already exists
Search the government EPC register by address at gov.uk/find-energy-certificate. If a certificate is less than 10 years old and the property has not changed significantly, it remains valid for selling or letting.
Commission a domestic energy assessor
If you need a new EPC, hire an accredited domestic energy assessor (DEA). Search for one using the Elmhurst Energy or NHER register, or ask your estate agent for a recommendation.
Prepare the property for the assessment
The assessor will inspect insulation, heating system, windows, lighting and the building fabric. Providing any documents (boiler installation certificate, cavity wall insulation guarantee, solar panel specs) helps achieve an accurate rating.
Receive and review your certificate
The assessor uploads the certificate to the government register and gives you a copy. Review the recommendations section to understand what improvements would raise the rating and by how much.
Make improvements and request a new assessment if needed
If you make significant upgrades, commissioning a new EPC demonstrates the improvements and can support a better mortgage rate, a higher rental income or a stronger selling position.
Landlords face tightening minimum standards
Rented homes in England and Wales must currently have a minimum EPC rating of E to be let legally, with limited exemptions. The government has consulted on requiring new tenancies to meet a C rating by 2028 and all tenancies by 2030, though final legislation has not yet been passed. If you are buying to let, factor the cost of potential upgrades into your purchase calculations now rather than later.
EPC ratings and mortgages: green deals and restrictions
Several major UK lenders now offer preferential 'green mortgage' rates for properties rated A or B. Barclays, NatWest, Nationwide and Halifax have all launched products that reduce the interest rate or offer cashback for energy-efficient homes. The saving is typically 0.1 to 0.2 percentage points compared to a standard equivalent deal, which on a £200,000 mortgage could save £200 to £400 per year.
At the other end of the scale, a very poor EPC rating (F or G) may raise concerns with lenders. Some lenders cap their LTV on poorly rated properties, and a surveyor's valuation might reflect the cost of required upgrades in the assessed value. As minimum standards tighten over time, lender policies on low-rated properties are expected to become stricter.