EPC Ratings Explained: Bands A–G

Every EPC gives a property a score under the Standard Assessment Procedure (SAP), then puts that score in a letter band from A to G. The letter on the certificate is the band your score landed in. The score normally runs from 1 to 100. A home that generates more energy than the model says it uses can score above 100, and it is still band A.

The score is modelled, not metered. It comes from the building itself: construction, insulation, glazing, heating, hot water and lighting, assessed under standard assumptions about how a home is used. So it does not change because you are careful with the thermostat.

The EPC band scale at a glance

Those ranges are fixed in the SAP specification (Table 14), so an EPC grade of D always means 55 to 68 points, whatever the property.

What is the average EPC rating?

The median home in England scores 69 SAP points, the bottom of band C. That figure comes from the Office for National Statistics, covering EPC records for new and existing homes in the ten years to March 2025. Wales is 68, a D. London's median is 70, a C, level with the East of England and the South East.

Our own count of London certificates for existing homes, lodged since January 2023, gives the spread behind that median:

The borough ratings data breaks the same figures down for each London borough.

Is an EPC rating of D good?

A D is acceptable but below average. The median home in England and in London is a C, so a D scores below the typical home. Whether that matters depends on what the certificate is for:

• Letting: a D clears today's minimum of band E for homes covered by the minimum standard.
• Selling: the letter goes in the listing. Buyers will see plenty of others: 32.8% of recent London certificates for existing homes are a D.
• Comparing two homes: check the score as well as the letter. A 68 is one point from a C, and a 55 is one point from an E.
• Running costs: on recent London EPCs, a typical home rated D had an estimated running cost of £1,160 a year, against £741 for C. The full table is in EPC running costs by band.

The band D section below covers what usually holds a D back.

Is an EPC rating of E good or bad?

E is the lowest band a home covered by the minimum standard can be let in without a registered exemption. In London, 4.6% of recent certificates for existing homes are band E, so it is well below average. Landlords with an E have no margin: if the next assessment records a lower score, the property drops below the minimum.

EPC rating A

Band A covers 92 SAP points or more and is the top of the scale. It is uncommon in existing housing.

Homes reaching band A are usually designed for it from the start: a very well-insulated shell, low-carbon heating, and often 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, read the certificate's detail rather than the letter alone. The measures behind it tell you what you are actually taking on.

EPC rating B

Band B is 81 to 91 points. Government guidance says most new homes built to current Building Regulations get a B or C.

Homes in this band usually combine good insulation with an efficient heating system, and often some renewable contribution. For most existing homes, B is the realistic ceiling without major building work.

EPC rating C

Band C runs from 69 to 80 points. It is the band most improvement work aims at, and the one most often mentioned in policy discussion.

A property in band C generally has the fundamentals right: reasonable insulation, working modern heating and efficient lighting, without anything exceptional. It is comfortably above the current minimum for letting.

EPC rating D

Band D covers 55 to 68 SAP points and sits in the middle of the A to G scale. Across London, 32.8% of EPCs lodged for existing homes since January 2023 are band D, so it is the band many people end up looking up.

What band D usually signals. A D generally means the basics are in place but something is holding the score back. Homes 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 working but dated boiler, or limited heating controls
• an uninsulated or thinly insulated hot-water cylinder
• lamps in permanent fittings that are not LED

None of those is universal. Two homes can both land in band D for different reasons, and the detail on the certificate tells you which apply to yours.

What it means in practice. A D is above the current minimum of band E for rented homes covered by the minimum standard, so on that basis alone a D does not stop a property being let. For a sale, a D is unremarkable 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. When you compare certificates, compare the scores and the recorded details, not just the letters. Our guide on why EPC ratings differ between similar homes explains why near-identical houses can still separate.

Moving from D to C is a separate question, covered in our D-to-C routes for common London homes.

EPC rating E

Band E is 39 to 54 points. It is below the middle of the scale, but at or above the legal minimum for letting a home covered by the minimum standard.

Homes here often have more than one limiting factor at once, such as an uninsulated wall type with older heating. Because E is the current threshold for rented property, landlords in this band have the least margin. Anything that later lowers 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 minimum standard, 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 part, commonly an uninsulated shell alongside inefficient or partial 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 usually combines an uninsulated building, no effective central heating and single glazing. Check the recorded details closely. Where a home has been improved but the work could not be inspected or evidenced, the method may have had to use a default assumption instead.

Current rating vs potential rating

Every EPC shows two ratings on its chart: the current rating and the potential rating.

The current rating is the home as the assessor found it on the day. It is the rating that counts. It is the letter that has to go in sale and letting adverts, and the one the letting minimum is measured against.

The potential rating is what the home could reach. GOV.UK's guidance says it "is based on all cost-effective recommendations being implemented", which means every suggested improvement listed on the certificate, done together. Three points follow from that:

• It is modelled in the same way as the current rating, and it assumes every listed improvement is carried out. Some of them may not suit your home or budget.
• It has no legal weight. A potential C does not let you rent out a home whose current rating is F.
• The current rating only changes when the work is done and a new EPC is lodged.

In London, 96.2% of the EPCs lodged for existing homes since January 2023 have a potential rating of C or above. Of the homes rated D to G today, 90.1% have a potential of C or above, so for most London homes below a C the certificate itself lists a way to reach one. Our guide to improving an EPC rating covers which measures to start with.

How the band is actually produced

Two points 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 checks any evidence they can accept. That data goes into government-approved software, which produces the SAP score and the band. The score is based on modelled energy costs. There is no field to adjust.

Evidence changes what can be recorded. Where an improvement cannot be inspected, such as insulation behind plasterboard, under a fitted floor or above a boarded loft, the method may require a default assumption based on the age of the building unless there is documentation for 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

This is a subject in its own right, so briefly.

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 confirmed a higher standard equivalent to EPC C for 1 October 2030, using reformed EPC metrics. Implementing legislation is still required. The current E minimum remains in force for rentals within MEES scope, unless a valid exemption is registered.

Want to move up a band?

This guide is about what the bands mean. Improving one is a separate job with its own decisions about cost and the order of works.

See our guide to improving an EPC rating, which covers routes from D to C for common London homes and what decides how much each measure helps.

Finding your current band

Every lodged EPC is on the government register. You can look up a certificate free on the GOV.UK find an energy certificate service by postcode, street or certificate number. If nothing shows, either no EPC has been lodged for the address or the owner has opted out of public search. Our guide to finding and checking your EPC shows how to read and save it.

If the certificate has expired, or the property has been improved since, 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.