How to Challenge a Wrong EPC Rating: Dispute and Reassessment Guide

If you believe your EPC rating is inaccurate, you have the right to challenge it. Incorrect EPCs are more common than many homeowners realise, and an error of just a few points can mean the difference between an EPC C and a D, affecting your property’s value, mortgage options, and eligibility for energy grants. This guide walks you through the step-by-step process for disputing an EPC, gathering evidence, contacting the original assessor, escalating to the accreditation scheme, and knowing when to commission a fresh assessment.

How to Challenge a Wrong EPC Rating

If you believe your EPC rating is incorrect — for example, if the assessor missed existing insulation or recorded the wrong heating system — you can dispute it through the following process:

1. Review your EPC certificate at gov.uk/find-energy-certificate and check every detail — wall type, insulation, glazing, heating system and hot water
2. Gather evidence of any errors, such as insulation guarantee certificates, building control sign-off documents or installer invoices
3. Contact the original EPC assessor and ask them to correct the certificate — they may offer a free revisit
4. If the assessor refuses or is unresponsive, complain to their accreditation scheme (listed on the EPC certificate)
5. The accreditation scheme will investigate and can order a reassessment at no cost to you
6. If still unresolved, commission a new EPC from a different accredited assessor — this typically costs £60–£100

Common EPC errors include recording solid walls when cavity walls are present, missing loft insulation that is covered by boarding, and failing to note a recently upgraded boiler. A wrong EPC can cost you thousands in unnecessary improvement work or affect your property’s sale price, so it is always worth checking the details carefully.

Why EPC Ratings Can Be Wrong

EPCs are produced by qualified Domestic Energy Assessors (DEAs), but the assessment process involves significant judgment calls and assumptions. Common reasons for inaccurate ratings include the following.

• Missed insulation: The assessor may not have identified cavity wall insulation, particularly if there are no visible drill holes or the property has been re-rendered
• Incorrect wall type: Distinguishing between solid walls and cavity walls is not always straightforward, especially in properties built during the 1920s-1940s transition period
• Assumed rather than measured: Where the assessor cannot verify a feature (e.g., loft insulation depth), they may use default assumptions that underestimate the property’s performance
• Recent improvements not recorded: If you have added insulation, replaced windows, or upgraded your boiler since the last EPC, these improvements will not be reflected
• Incorrect property dimensions: Errors in floor area measurements affect the entire calculation
• Wrong heating system data: The assessor may have recorded the wrong boiler model, fuel type, or heating control configuration

Research suggests that a significant proportion of EPCs contain at least one error that could affect the rating by one or more points. For properties on the borderline between grades, this can push the rating into a lower band than it deserves.

Step 1: Review Your Current EPC for Errors

Before taking any action, carefully review your EPC document. You can find it on the government’s EPC register by searching your postcode. Check the following details for accuracy.

Property Details

• Is the property type correct (detached, semi-detached, terraced, flat)?
• Is the total floor area accurate?
• Is the number of storeys correct?
• Is the property age band correct?

Wall Construction

• Are the walls described as solid or cavity? Is this correct?
• If cavity, does the EPC show them as insulated or uninsulated?
• If you have had cavity wall or external wall insulation installed, is this reflected?

Insulation

• Is the loft insulation depth recorded correctly?
• Is floor insulation noted if present?
• Are double-glazed windows correctly recorded?

Heating System

• Is the correct boiler make and model listed?
• Are heating controls (programmable thermostat, TRVs) accurately described?
• If you have a heat pump, is it correctly recorded?

Make a list of every item you believe is incorrect. The more specific your evidence, the stronger your case for a reassessment.

Step 2: Gather Evidence of Improvements

To support your challenge, gather documentation proving the correct state of your property. Useful evidence includes the following.

• Insulation certificates: CIGA (Cavity Insulation Guarantee Agency) certificates for cavity wall insulation, installer receipts for loft insulation
• Building control sign-off: Completion certificates for any work that required Building Regulations approval
• Boiler installation records: Gas Safe certificate, commissioning records showing the exact boiler model and efficiency rating
• Window FENSA certificates: Self-certification documents for replacement double glazing
• Photographs: Photos showing insulation depth in the loft, boiler model plate, window specifications
• Receipts and invoices: From contractors who carried out improvements
• Previous EPCs: If an earlier EPC recorded features correctly that the current one has missed

Step 3: Contact the Original Assessor

Your first port of call should be the assessor who produced the EPC. Their name and accreditation details appear on the EPC document.

• Contact the assessor in writing (email is ideal for creating a record)
• Explain which items you believe are incorrect
• Provide copies of your supporting evidence
• Request a review of the assessment and correction of any errors

Many assessors will correct genuine errors without charge, as inaccurate EPCs reflect poorly on their professional standing. If the assessor agrees that corrections are needed, they will amend the EPC on the central register and issue you with an updated certificate.

The assessor should respond within 10 working days. If they agree to a correction, the updated EPC should appear on the register within a further five working days.

Step 4: Escalate to the Accreditation Scheme

If the original assessor refuses to correct the EPC or does not respond, you can escalate your complaint to their accreditation scheme. Every DEA must be registered with an approved accreditation body. The main ones are as follows.

• Elmhurst Energy
• Stroma Certification
• ECMK
• Sterling Accreditation
• Quidos

To escalate, submit a formal complaint to the accreditation body, including your evidence and a record of your correspondence with the assessor. The accreditation body will investigate the complaint and may take the following actions.

• Review the EPC data and request the assessor to amend it
• Arrange an independent audit of the assessment
• Take disciplinary action against the assessor if the error was due to negligence or incompetence
• In serious cases, suspend or revoke the assessor’s accreditation

Accreditation bodies are required to have formal complaints procedures and typically aim to resolve disputes within 20 to 30 working days.

Step 5: Commission a Fresh EPC Assessment

If the dispute process does not resolve the issue, or if you want a faster resolution, you can simply commission a new EPC from a different assessor. This is often the most pragmatic approach, particularly if the following apply.

• You have made improvements since the last EPC that justify a new assessment
• The original assessor is unresponsive or uncooperative
• You need an accurate EPC urgently (for a sale, letting, or grant application)

A new EPC assessment costs 60 to 120 and takes about 45 minutes to an hour on-site. When booking the new assessment, take the following steps to ensure accuracy.

• Have all your evidence ready for the assessor to review
• Show the assessor your loft space so they can measure insulation depth
• Point out the boiler model plate and any heating controls
• Provide copies of CIGA certificates, FENSA certificates, and Building Control sign-offs
• Walk through the property with the assessor and highlight any features they might miss

Being proactive during the assessment significantly reduces the chance of errors. An assessor who has access to documentation and can verify features firsthand will produce a much more accurate EPC.

Common EPC Errors and Their Impact on Your Rating

A property that has cavity wall insulation missed and loft insulation underestimated could be 7-15 points lower than it should be. That is easily enough to push a borderline C down to a D, or a D down to an E.

If you need to improve your EPC rating for MEES compliance, a grant application, or property sale, correcting errors is the first and cheapest step. If corrections alone are not enough, get a free quote for the most cost-effective improvements to reach your target rating.

Frequently Asked Questions

How long does an EPC dispute take to resolve?

If the original assessor cooperates, corrections can be made within two to three weeks. If you need to escalate to the accreditation body, expect four to eight weeks for resolution. Commissioning a completely new EPC from a different assessor can be done within a week, making it the fastest option when time is critical.

Can I challenge an EPC rating that was correct when issued but my property has since improved?

An EPC that was accurate at the time of assessment cannot be challenged as incorrect. If you have since made improvements such as adding insulation, replacing your boiler, or installing solar panels, you need to commission a new EPC to reflect the current state of the property rather than challenging the old one.

Does challenging an EPC affect its validity?

No. The EPC remains valid throughout the dispute process unless it is formally amended or replaced. If you are selling or letting the property during a dispute, the existing EPC is still legally valid even if you believe it is inaccurate. Once corrected or replaced, the new version supersedes the old one on the register.

Can I request a specific assessor for a new EPC?

Yes. You are free to choose any accredited Domestic Energy Assessor for a new EPC. It is worth checking reviews, asking for recommendations, and choosing an assessor who is thorough and willing to spend time verifying features rather than relying on assumptions. A good assessor will ask to see your loft, check the boiler plate, and request any certificates you hold.