Energy billing disputes are the most common complaint raised with the Energy Ombudsman in the UK, accounting for over half of all cases they handle. If your energy supplier has sent you an incorrect bill, failed to respond to your concerns, or provided poor service, you have clear legal rights and a defined process to follow. This guide explains exactly what to do.
Your Rights as an Energy Consumer
As an energy consumer in the UK you are protected by regulations enforced by Ofgem, the independent energy regulator. These regulations are underpinned by the Gas Act 1986 and the Electricity Act 1989. Under these rules your energy supplier must provide accurate bills, respond to complaints in a timely manner, and resolve issues within eight weeks of a formal complaint being raised.
Since January 2025, automatic compensation payments under Ofgem's Guaranteed Standards of Performance increased to £40 per failure. This covers missed engineer appointments, delayed switches, late final bills, and late credit refunds. In many cases this compensation should be paid automatically without you needing to claim — but if it is not paid within ten working days of the failure, you are entitled to request it formally.
Common Valid Grounds for Complaint
The most common reasons to complain to your energy supplier include inaccurate bills based on wrong meter readings or excessive estimates, bills you do not recognise or that contain unexplained charges, back-billing beyond twelve months where the supplier was at fault for the billing error, missed engineer appointments, delayed switching between suppliers, failure to refund credit on your account, and poor customer service or failure to respond to previous contact.
On back-billing specifically — if your supplier has made an error and failed to bill you correctly, they can only recover charges from the last twelve months. They cannot back-bill you for energy used more than twelve months ago if the error was their fault. This is an important protection many consumers are unaware of.
The Four Stage Complaints Process
Energy complaints follow a defined four stage process and it is important to follow each stage in order.
Stage one is the initial complaint. Contact your energy supplier directly and explain the problem clearly in writing. Email is preferable to phone as it creates a written record. Include your account number, a clear description of the issue, any relevant dates, and the outcome you are requesting. Your supplier must acknowledge your complaint within a few working days and begin an investigation.
Stage two is internal escalation. If your complaint is not resolved at the first stage, ask for it to be escalated to a senior complaints handler or complaints manager. Keep a record of every contact including dates, times, names of people you spoke to, and any reference numbers given.
Stage three is the eight week deadline. Under Ofgem rules your supplier must resolve your complaint within eight weeks. Make a note of the date you first raised your formal complaint. If eight weeks pass without a satisfactory resolution you are entitled to escalate to the Energy Ombudsman regardless of where the complaint stands internally.
Stage four is the Energy Ombudsman. If your supplier issues a deadlock letter stating they cannot resolve the complaint to your satisfaction, or if eight weeks have passed without resolution, you can refer your case to the Energy Ombudsman. The service is completely free for consumers and the Ombudsman's decisions are binding on suppliers. You must contact the Ombudsman within twelve months of your supplier's final response.
What the Energy Ombudsman Can Award
The Energy Ombudsman can require your supplier to apologise formally, correct your account and bills, pay compensation for inconvenience and distress, and take specific practical action to resolve the issue. Compensation amounts vary but cases resolved through the Ombudsman often result in higher awards than the statutory minimums. The Ombudsman handles around 100,000 complaints each year and is a genuinely effective escalation route.
How to Write an Effective Complaint Letter
The quality of your initial complaint letter matters. A vague or emotional complaint is easier for a supplier to dismiss. A formal, specific letter that references your account details, cites the relevant Ofgem standards, states the exact outcome you require, and sets a clear deadline is taken seriously.
Your complaint letter should include your full name and address, your account number, a clear factual description of the problem with dates, reference to the relevant Ofgem Guaranteed Standard if applicable, the specific outcome you are requesting, and a fourteen day deadline for a response before you escalate further.
Keep the tone professional and factual throughout. State what happened, what you want done about it, and what you will do if it is not resolved. That structure alone puts you ahead of most complaints suppliers receive.
If you need guidance on writing other types of formal letters, the Appeal Letters blog covers disputes including parking fine appeals and landlord deposit disputes.
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