EPC ratings explained: what the certificate says and what depends on it
By the Offrano editorial team · · 4 min read
Most people meet the Energy Performance Certificate twice: when they buy a home and when they sell or let it. In between it tends to sit in a drawer. Yet the letter on it, from A to G, now decides whether a landlord in England and Wales may let a property, whether a low-income household qualifies for some grants, and what an installer is likely to recommend. This guide explains what the certificate measures, what it does not, and where it carries legal or financial weight.
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What the certificate actually contains
An EPC gives a property an energy efficiency rating from A, the best, to G, the worst. It also shows information about the home's energy use and typical energy costs, and a list of steps that could improve its efficiency. It is valid for 10 years.
The rating comes from a standardised assessment by an accredited energy assessor: construction, insulation, windows, heating system, controls and lighting are recorded and fed into a calculation. It describes the building under standard assumptions about occupancy and heating, not your household's real bills. Two identical houses get the same rating whether one is heated all day and the other only in the evening.
Source: gov.uk
When you must have one
You need an EPC when you sell a property, rent one out or build a new one, and it has to be ordered before the property is marketed to buyers or tenants. In Scotland, the EPC must also be displayed somewhere in the property, for example in the meter cupboard or next to the boiler.
Anyone can look up an existing certificate for an address on the government's energy certificate register for England, Wales and Northern Ireland. Checking before you commission a new assessment is worthwhile: a certificate from a few years ago may still be valid, although it will not reflect improvements made since.
Landlords: the E rule in England and Wales
Under the Minimum Energy Efficiency Standard regulations, landlords of most privately rented homes in England and Wales cannot let, or continue to let, a property with an EPC rating below E unless a valid exemption is registered. This has applied since 1 April 2020. A property rated F or G has to be improved to E before a new tenancy, or immediately if it is already let.
The regulations include a cost cap on what a landlord must spend, and exemptions where improvements have been made up to that cap and the property is still below E, where no recommended measure can be installed within it, or where consent from a third party is refused. Exemptions have to be entered on the PRS Exemptions Register, and most last five years. The government has said it aims for as many privately rented homes as possible to reach band C by 2030, but that is a stated aim rather than a legal requirement at present.
Source: gov.uk
Why grant schemes ask for your EPC
Several schemes use the rating to target help. The Warm Homes: Local Grant in England is aimed at low-income households in privately owned homes rated D to G. ECO4, funded by energy suppliers, also works from the property's starting rating. Home Energy Scotland asks for a valid EPC before it funds some insulation measures.
That makes an out-of-date or inaccurate certificate a practical problem. If your EPC predates insulation, a new boiler or double glazing, it may understate your home, or, if it was generous, overstate it and make you ineligible. An installer or assessor can tell you whether a new assessment is worth having before you apply.
Source: gov.uk · homeenergyscotland.org
Reading the recommendations with care
The recommendations on an EPC are generated from the assessment, not from a survey of your particular walls or roof. They are a starting list, not a specification. A recommendation for solid wall insulation, for example, does not tell you whether internal or external insulation suits the building, whether a conservation area limits the options, or how damp will be managed.
For landlords, the list matters more: the regulations refer to the recommended measures when deciding whether all relevant improvements have been made. Installing a measure that is not recommended, and still ending below E, does not give access to the corresponding exemption.
- check the date and the assessor's notes against what the house has today
- treat the recommendations as a shortlist for a proper survey
- keep invoices and certificates for any work, so a new assessment can record it
- if you let the property, keep the EPC and any exemption registration together
When a new assessment is worth it
A new EPC makes sense after significant work such as loft or cavity insulation, a new heating system or replacement glazing, before applying for a grant that depends on the rating, and before marketing a property if the old certificate has expired. For deciding what to do to a home, a fuller retrofit or energy assessment gives more than an EPC can, because it looks at the building rather than filling a standard model.
If you want an energy assessment or a new certificate, you can describe the property in our request form. It goes to exactly one assessor or energy adviser in your area who buys it; before that business receives your details, we email you its name, address and phone number. The request costs you nothing.