EPC guide 13
When an EPC looks wrong
It is not unusual to read a certificate and recognise very little of your own home in it. Sometimes that is a misunderstanding of how the rating works, and sometimes the record genuinely does not describe the property. This guide sets out the common causes and the practical routes available for having a certificate looked at again.
Why a record drifts out of step
The most common reason is simply time. An EPC is a snapshot of the property on the day it was assessed, and a domestic certificate is normally valid for ten years. A loft topped up, a boiler replaced, windows upgraded or a cavity filled after that date will not appear on the existing certificate, because nobody has been back to look.
The other causes are errors in the data itself. Wall construction can be recorded as solid when it is cavity, or as unfilled when insulation was installed years ago. Heating type, controls or the fuel used can be logged incorrectly. Floor area is a particularly influential field, and a measurement or transcription mistake there can move the modelled result noticeably. Extensions and conversions are easy to miss or double-count.
Assumed is not the same as observed
Existing homes are assessed by an accredited Domestic Energy Assessor using RdSAP, a standardised method that works from a defined set of inputs; new builds are assessed under the full SAP calculation instead. Where an assessor can see something directly – a boiler badge, a loft hatch, a window frame – they record it. Where they cannot, the method requires them to apply a default based on the age and type of the building. Those defaults are cautious by design, and a cautious default usually reads worse than the reality.
That distinction matters, because it explains a certificate that looks unfair without anyone having made a mistake. If a wall is plastered and there is no paperwork to hand, the assessment may fall back on “as built” for a home of that vintage. Nothing has been done wrongly; the evidence simply was not available. Our guide to reading an EPC explains where those assumptions show up on the certificate.
Evidence worth digging out first
- Cavity wall or loft insulation guarantees, installer certificates and any CIGA paperwork.
- Boiler make, model and installation or servicing records, plus Gas Safe or building control notices.
- Window and door certificates, including FENSA or CERTASS registrations.
- MCS certificates for a heat pump, solar panels or other renewable technology.
- Building control completion certificates for extensions, loft conversions or a new roof.
- Photographs taken during the work, especially of insulation before it was covered up.
Start with the paperwork
Before contacting anyone, gather what you can prove. A query supported by an installer certificate or a building control notice is far easier to resolve than one based on recollection. Read the certificate line by line against the house and note precisely which fields you believe are wrong, rather than objecting to the band as a whole.
Be prepared for the possibility that the data is right and the outcome still feels disappointing. The efficiency rating is cost-based, modelling the estimated cost of heating, hot water and lighting under standard occupancy. A measure can cut carbon and improve comfort without shifting the band much, and that is a feature of the methodology rather than a fault in the certificate. The recommendations section is modelled on the same basis, so it inherits any input that was wrongly recorded.
Why accuracy matters for a let property
An understated record can matter beyond appearances. Under the minimum energy efficiency standards, since 1 April 2020 a property in England and Wales generally cannot be let with a rating below band E unless a valid exemption has been registered. If the certificate shows F or G because insulation or a heating upgrade was never captured, correcting the record is the first thing to look at.
A higher minimum standard of band C has been proposed and consulted on, but it is not settled law and no requirement should be treated as fixed until the final rules are confirmed. Our guide for landlords sets out the current position, and GOV.UK remains the place to confirm it.
Raising it with the assessor
The certificate names the assessor who produced it and the accreditation scheme they belong to. The usual first step is to contact that assessor or their firm directly, explain which entries you think are inaccurate and share the supporting documents. Queries are often settled at this stage, particularly where evidence has come to light that was not available on the day.
What happens next depends on the nature of the issue and the scheme’s own procedures. A confirmed data error may be amended or a corrected certificate lodged; a change to the property itself normally calls for a new assessment instead. Keep your correspondence in writing so there is a clear record of what was raised and when.
The accreditation scheme route
An accredited Domestic Energy Assessor belongs to an approved accreditation scheme, and schemes operate complaints procedures and quality checks over their members’ work. If the assessor does not respond, or you are not satisfied with the answer, the scheme is the next port of call.
Schemes generally expect you to have approached the assessor first, so keep that correspondence to hand. Timescales and the exact process vary between schemes, and the current guidance on energy certificates and how they are regulated is published on GOV.UK, which is the authoritative place to check before escalating.
When a new assessment is cleaner
If the home has genuinely changed since the certificate was produced, a complaint is the wrong instrument. Commissioning a fresh assessment is usually the more direct answer: the newest certificate becomes the current one for the property once it is lodged on the national register. Fees are not fixed and vary by property, location and assessor, often somewhere in the region of £60 to £120.
Have your evidence ready for the visit so the new assessment records what has actually been installed rather than a default. Our guide to getting an EPC covers booking, the visit itself and how the certificate is issued. No assessor can promise a particular band in advance, and you should treat any who does with caution.
Where the property is matters too
Energy performance is a devolved matter, so the certificate itself, the assessment arrangements and the rules that sit around them are not identical across the UK. Scotland and Northern Ireland operate their own systems, and the route for questioning a certificate follows the arrangements that apply there rather than those for England and Wales.
Older and traditionally built homes raise their own questions, and exemptions such as those sometimes discussed for listed buildings are nuanced rather than automatic: whether one applies depends on the individual property and on the specific measures involved, so check the current position on GOV.UK or with the relevant national body. Our guide to EPCs across the UK covers the main differences.
What we can and cannot do here
EPC Checker reads the public register and presents what is recorded there. We cannot amend, withdraw or re-issue an official certificate, and nothing shown on this site changes the record. Only the assessor, working through their accreditation scheme, or a new lodged assessment can do that.
What this site is useful for is preparation: seeing exactly which features and assumptions were recorded, so you can pin down the specific entries you want reviewed. Treat it as a research aid over public data, not as an assessment or a survey. Anything said here about costs or fees is general information, not financial advice, and it is not legal advice either.