Energy overcharge claim UK 2026: how to reclaim money from your energy supplier

Chandraketu Tripathi

Finance Editor, Kaeltripton

Published 10 May 2026

Last reviewed 10 May 2026

✓ Fact-checked

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TL;DR

If your energy supplier has charged you more than the Ofgem price cap unit rate or applied incorrect standing charges, you are entitled to a refund of the difference. Raise a formal complaint with your supplier first. If unresolved within eight weeks, escalate free of charge to the Energy Ombudsman. Keep meter reading records and check every bill against the current cap rates at ofgem.gov.uk.

Energy overcharging is one of the most frequently raised consumer complaints in the UK utility sector. It can occur in several ways: a supplier charging unit rates above the Ofgem price cap; errors in reading meters resulting in inflated estimated bills; applying the wrong tariff code or standing charge; incorrectly billing for a property you have vacated; or failing to apply an agreed discount or concession. In each case, your supplier is required under Ofgem's supply licence conditions to investigate promptly, correct any error, and refund any overpayment.

Overcharging complaints are handled initially through each supplier's internal complaints process; Ofgem does not handle individual consumer complaints directly. If a complaint is unresolved after eight weeks, or if the supplier issues a final response you disagree with, you can refer the matter to the Energy Ombudsman free of charge. The Ombudsman can direct the supplier to repay money owed and can award compensation for distress and inconvenience. This guide covers how to identify an overcharge, the formal complaint process, and how to use the Ombudsman service.

Key facts (2026)

Energy suppliers must investigate complaints within eight weeks and issue a final response letter (deadlock letter) if the complaint is unresolved (Ofgem supply licence conditions).
The Energy Ombudsman is the approved Alternative Dispute Resolution (ADR) scheme for the energy sector; its decisions are binding on the supplier if the consumer accepts the resolution (Energy Ombudsman Service).
Suppliers must refund credit balances on request within 10 working days if the account is in credit due to overpayment (Ofgem licence condition SLC 27A).
The Ofgem price cap unit rates and standing charges for your region are published quarterly at ofgem.gov.uk; any bill charging above these rates on a variable tariff is potentially an overcharge (Ofgem).
Suppliers are required to backbill no more than 12 months for energy consumed due to their own metering or billing error; you cannot be charged for consumption more than 12 months old if the error was the supplier's fault (Ofgem backbilling rules).

How to identify if you have been overcharged

The first step is to compare your bill against the Ofgem price cap rates for your region and tariff type, available at ofgem.gov.uk. Check that the unit rate per kWh for electricity and gas on your bill does not exceed the current cap rate for your distribution network operator (DNO) area. Also check the daily standing charge. If you are on a fixed tariff, compare against your contract rate rather than the cap. For estimated bills, check whether the meter reading estimate is consistent with your actual consumption - if your household has reduced usage significantly but the estimated bill has not reduced, you may be over-estimated. Always submit actual meter readings to your supplier online or by phone to override estimated billing. For direct debit customers, check whether the monthly direct debit amount is consistent with your actual usage and whether you have built up a large credit balance that has not been drawn down.

Making a formal complaint to your supplier

Raise the overcharge as a formal complaint in writing - by email or through the supplier's online complaints portal - rather than as a general enquiry. A formal complaint triggers the supplier's regulated complaints handling process and the eight-week resolution clock. In your complaint, clearly state: what you believe you have been overcharged, the specific bills or periods affected, the evidence you are relying on (the Ofgem cap rates, your meter readings, any previous correspondence), and what resolution you are seeking - typically a refund of the overcharged amount plus interest if the overpayment has been held for a significant period. Keep a copy of every communication. The supplier must acknowledge your complaint promptly and issue either a resolution or a final response (deadlock letter) within eight weeks. If the complaint is resolved to your satisfaction, obtain written confirmation of the refund amount and the payment date.

Reclaiming credit balances

If you have overpaid through inflated direct debits and your account is in credit, you can request a refund of the credit balance at any time. Under Ofgem licence condition SLC 27A, suppliers must return a credit balance within 10 working days of a request, unless there are reasonable grounds to withhold it - for example, if a final bill has not yet been issued after moving home, or if the account is disputed. Submit the refund request in writing and keep evidence of the date submitted. If the supplier fails to issue the refund within 10 working days without a valid reason, raise this as a formal complaint. Persistent refusal to return a credit balance is a breach of Ofgem licence conditions and can be reported to Ofgem's consumer team, though individual enforcement is handled through the Ombudsman rather than Ofgem directly.

The 12-month backbilling rule

The backbilling protection rule prevents suppliers from charging you for energy consumed more than 12 months ago if the underbilling was caused by the supplier's error or a metering fault. For example, if your meter was incorrectly calibrated for two years causing your bills to be lower than the actual consumption, and the supplier then issues a catch-up bill for two years of underpayment, you are only required to pay the most recent 12 months of the underpayment. The older portion cannot be charged. This rule protects consumers from large unexpected bills caused by supplier errors and is set out in Ofgem's backbilling guidance and in the supplier licence conditions. Note that the rule applies when the undercharging was caused by the supplier's fault; if you have consistently refused meter access and the supplier was unable to obtain accurate readings, different rules may apply.

Escalating to the Energy Ombudsman

If your supplier does not resolve the complaint within eight weeks, or issues a final response you disagree with, you can refer the matter to the Energy Ombudsman free of charge. Apply online at ombudsman-services.org/energy or by post. Provide the complaint reference number, copies of all correspondence, the deadlock letter if issued, and evidence supporting your claim. The Ombudsman will investigate independently and can direct the supplier to: repay overcharged amounts, apply a credit to your account, provide a goodwill payment for inconvenience, and write a letter of apology. Ombudsman decisions are binding on the supplier if you accept the resolution; you are not obliged to accept and can pursue the matter through the courts if you prefer. The Ombudsman's service is free; no claims management company is required or needed.

Related guides

Frequently asked questions

How do I check if my energy bill exceeds the price cap?

Go to ofgem.gov.uk and find the current quarterly cap unit rates and standing charges for your region. Compare these with the unit rate and daily standing charge on your bill. If your bill shows higher rates than the Ofgem cap for a variable tariff, raise a formal complaint with your supplier immediately. The Ofgem website also provides a bill checker tool to help you verify whether your rates are correct.

Can my supplier refuse to refund a credit balance?

Suppliers can only withhold a credit balance refund in limited circumstances, such as where a final bill is pending after you move home, or where there is an active dispute about the account balance. If neither applies and the supplier refuses to refund within 10 working days of your written request, raise a formal complaint. Persistent refusal without valid grounds is a breach of Ofgem licence conditions and can be referred to the Energy Ombudsman.

Can a supplier charge me for energy used more than 12 months ago?

Not if the underbilling was caused by the supplier's error or metering fault. The Ofgem backbilling rule prevents suppliers from recovering more than 12 months of consumption that was undercharged due to their own failure. If you have been sent a large catch-up bill, check whether any portion relates to consumption more than 12 months before the bill date caused by a supplier error. If so, challenge the older portion formally in writing.

Do I need a claims management company to complain about energy overcharging?

No. The energy complaint and Ombudsman process is entirely free to consumers without any intermediary. Claims management companies have no special access to the Energy Ombudsman and charge fees for a service you can do yourself at no cost. The Energy Ombudsman's online application is straightforward and Citizens Advice provides free support if you need help completing it.

What compensation can the Energy Ombudsman award?

The Energy Ombudsman can direct a supplier to repay overcharged amounts, apply credits to your account, and pay a goodwill award for distress and inconvenience. Goodwill awards in energy cases typically range from £30 to £250 depending on the severity and duration of the problem. The Ombudsman can also require the supplier to take specific remedial action and provide a written apology. There is no cap on the repayment of overcharged amounts.

How we verified this guide

All complaint rights and Ofgem rules were verified against Ofgem supply licence conditions (SLC 27A), Ofgem backbilling guidance, Energy Ombudsman process documentation, and Citizens Advice energy complaint resources during May 2026. We do not accept payment from energy suppliers or claims management companies.

Disclaimer: This guide is information only, not financial, legal or tax advice. Rules and rates change. Always check the primary sources cited and take independent advice for your own circumstances.

Primary sources

Last reviewed: May 2026.