Every EPC gives a property a score from 1 to 100 under the Standard Assessment Procedure, then maps that score to a letter band from A to G. The letter on the certificate is just the band your score landed in.
The score is modelled, not metered. It comes from the building itself — construction, insulation, glazing, heating, hot water and lighting — so it does not change because you are careful with the thermostat.
The EPC band scale at a glance
Those SAP ranges are fixed by the methodology, so an EPC grade of D always means 55–68 points, whatever the property.
EPC rating A
Band A covers 92 to 100 SAP points and is the top of the scale. It is genuinely uncommon in existing housing.
Properties reaching band A are typically designed for it from the outset — a very well-insulated envelope, low-carbon heating, and usually on-site generation such as solar PV. Reaching A by retrofitting an older home is possible but rarely straightforward.
If you are buying and see an A, it is worth reading the certificate's detail rather than the letter alone: the measures behind it tell you what you are actually inheriting.
EPC rating B
Band B is 81 to 91 points, and is where a lot of modern construction sits.
Homes in this band usually combine good fabric insulation with an efficient heating system, and often some renewable contribution. For most owners, B is the realistic ceiling without significant structural work.
EPC rating C
Band C runs from 69 to 80 points. It is the band most improvement work targets, and the one most often mentioned in policy discussion.
A property in band C generally has the fundamentals right — reasonable insulation, functional modern heating, efficient lighting — without necessarily having anything exceptional. It is comfortably above the current minimum for letting.
EPC rating D
Band D covers 55 to 68 SAP points and sits squarely in the middle of the A–G scale. It is also, by some distance, the band people most often look up — which is worth a little more detail.
What band D usually signals. A D generally means the basics are in place but something meaningful is holding the score back. Properties in this band may have:
- solid walls, or cavity walls that have not been filled
- partial loft insulation, or insulation that could not be inspected on the day
- older glazing, or a mix of glazing ages across the property
- a functional but dated boiler, or limited heating controls
- an uninsulated or under-insulated hot-water cylinder
- a low proportion of fixed low-energy light fittings
None of those is universal. Two properties can both land in band D for completely different reasons, and the certificate's own detail is what tells you which reason applies to yours.
What it means practically. A D is above the current MEES minimum of band E, so a rented property in band D is not, on that basis alone, prevented from being let. For sale, a D is unremarkable — it is neither a selling point nor an obstacle in most of the market.
One caution on comparisons. Band D spans fourteen SAP points, so two homes can both be "a D" and be some distance apart. A 56 and a 68 are very different properties. If you are comparing certificates, compare the scores and the recorded details, not just the letters. Our guide on why EPC ratings differ between similar homes goes into why near-identical houses can still separate.
EPC rating E
Band E is 39 to 54 points — below average, but still at or above the legal minimum for letting a domestic property under MEES.
Properties here often have more than one limiting factor at once: an uninsulated wall type combined with older heating, for example. Because E is the current threshold for rented property, landlords in this band have the least margin. Anything that later reduces the recorded score could take a property below the minimum at its next assessment.
EPC rating F
Band F covers 21 to 38 points. Under the MEES Regulations, a property in band F cannot normally be let unless a valid exemption is registered.
An F generally reflects several significant issues together rather than one weak component — commonly an uninsulated envelope alongside inefficient or non-central heating.
EPC rating G
Band G is the lowest, at 1 to 20 points. As with F, a property in band G cannot normally be let without a registered exemption.
Band G is usually a combination of an uninsulated building fabric, no effective central heating, and single glazing. It is worth checking the recorded details closely: where a home has genuinely been improved but the work could not be inspected or evidenced, the methodology may have had to apply a default assumption instead.
How the band is actually produced
Two things are worth being clear about, because they cause most of the confusion.
The assessor does not choose the band. An accredited Domestic Energy Assessor surveys the property, records its measurements, construction, insulation, glazing, heating, hot water and lighting, and verifies any evidence they can accept. That data goes into government-approved software, which produces the SAP score and the band. There is no field to adjust.
Evidence changes what can be recorded. Where an improvement cannot be inspected — insulation behind plasterboard, under a fitted floor, or above a boarded loft — the methodology may require a default assumption unless there is documentation confirming what was installed. That default can be less favourable than reality. Our preparation and evidence guide sets out what is worth having to hand.
What your band means if you rent the property out
Keeping this short, because it is a subject in its own right.
Under the Minimum Energy Efficiency Standard, since 1 April 2020 landlords cannot let or continue to let a property covered by the regulations if it has an EPC rating below band E, unless a valid exemption is registered. GOV.UK's landlord guidance sets out the exemptions and how to register them.
Government has committed to look at a longer-term trajectory for privately rented homes, with the aim of upgrading as many as possible to EPC band C or equivalent by 2030. That is a stated aim rather than a current legal requirement, and the detail is still to be confirmed — so treat band C as a direction of travel, not today's threshold.
Want to move up a band?
This article is about what the bands mean. Improving one is a separate job with its own decisions about cost and order of works.
See our guide to improving an EPC rating, which covers which measures tend to earn the most points and what they typically involve.
Finding your current band
Every lodged EPC is public. You can look up an existing certificate free on the GOV.UK find an energy certificate service using the property's postcode.
If the certificate has expired, or the property has been improved since it was produced, a new assessment is the only way to get a current band. We cover all 32 London boroughs from our base in Stratford — see what a domestic EPC includes, the guide pricing, or send us the address for an exact quote.
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Frequently asked questions
Band D covers SAP scores from 55 to 68, which places a property in the middle of the A–G scale. In practice it usually means the essentials are in place but something meaningful is limiting the result — often wall construction, glazing, or a heating system that is functional but dated. A D is above the current minimum for letting a property under MEES, which is band E.
There are seven: A (92–100 SAP points), B (81–91), C (69–80), D (55–68), E (39–54), F (21–38) and G (1–20). A is the most efficient. The letter you see on the certificate is simply the band your SAP score falls into.
Band C or above is generally regarded as good for an existing home, and comfortably clears the current MEES minimum of E for rented property. What is realistic depends heavily on the building — a solid-walled period property and a recent new-build start from very different places.
Band G is the lowest, covering SAP scores of 1 to 20. A property in band G cannot normally be let under the MEES Regulations unless a valid exemption is registered, since the minimum is band E. It usually indicates several significant issues at once rather than one weak point.
An accredited Domestic Energy Assessor surveys the property and records its measurements, construction, insulation, glazing, heating, hot water and lighting, along with any evidence they can accept for features that cannot be inspected. That data is entered into government-approved software, which calculates the SAP score and the resulting band.
No. The assessor's role is to record the property accurately. The band is produced by the approved methodology and software from that data, so there is no field an assessor can edit to reach a requested result.
Related guides
How to Improve Your EPC Rating: Costs and Point Gains
A ranked list of EPC improvements, from LED bulbs (£50) to heat pumps (£15,000), with realistic D to C paths for Victorian terraces and 1930s semis.
Why Is My EPC Rating Different From My Neighbour's?
Two near-identical London homes can score differently on an EPC. Mid-terrace vs end-terrace, insulation, evidence and the RdSAP 10 methodology change all play a part.
MEES Regulations 2026: Landlord EPC Rules and Fines
MEES requires rented homes in England and Wales to be EPC band E or above. What the rules mean in 2026, the fines that apply, and how London landlords comply.
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