How to complain about your energy supplier

Energy complaints follow a different rhythm from public-sector ones. Ofgem's complaints handling standards require every domestic supplier to have a published complaints procedure, but there are no fixed internal stages. Instead there is one hard rule: once 8 weeks have passed since you first complained, or the supplier sends you a “deadlock letter” saying it can do no more, you gain the right to take the complaint to the Energy Ombudsman, free of charge, and the ombudsman's decision binds the supplier.

That makes the date of your first complaint the most important fact in the whole process. Complain in writing (email or the supplier's complaints form), say clearly that it is a formal complaint, and keep the date; the 8-week clock runs from it.

The stages at a glance

01Stage 1: Formal complaint to your supplier
Response: 8 weeks (about 40 working days)
Contact the supplier's complaints team, not just general customer service chat, and state what went wrong, the account and meter details, and what you want done. Suppliers must try to resolve complaints and tell you about the ombudsman if they can't. If at any point they conclude they cannot resolve it, they should issue a deadlock letter, which unlocks the ombudsman immediately without waiting out the 8 weeks.
02Stage 2: Energy Ombudsman
Free and independent. You can go to the Energy Ombudsman once 8 weeks have passed or you hold a deadlock letter, and normally within 12 months of that letter. It can require an apology, an explanation, practical action (such as correcting bills or meter records) and financial awards. If you accept its decision, the supplier must comply; if you reject it, you keep your legal rights.

The 8-week rule is set in calendar weeks, not working days. TrackMyComplaints' template approximates it as 40 working days so the reminder lands around the right day. The clock starts on the day you first complained.

Rules that often decide energy complaints

A lot of energy complaints are already covered by specific protections, and quoting the right one shortens the argument considerably:

Back-billing: a supplier cannot bill you for energy used more than 12 months ago if the delay in billing was its fault.
Guaranteed Standards: fixed compensation applies to certain failures, such as missed appointments and delayed switches, without you having to prove loss.
Prepayment and vulnerability: suppliers face extra obligations before installing prepayment meters or disconnecting, especially where someone in the household is vulnerable.
Ofgem itself does not investigate individual complaints; it sets the rules and fines suppliers for systemic failures. Your individual route is the supplier, then the ombudsman.

What to keep as evidence

Energy disputes are usually won on numbers and dates: what the meter said, what the bill claimed, and when you told the supplier.

Dated meter readings; photographs with the meter serial number visible are ideal.
Every bill and statement covering the disputed period, and your tariff details.
The date of your first complaint and the supplier's responses; the 8-week clock and the ombudsman both turn on these.
Notes of every call: date, agent name, and what was promised. Ask for promises to be confirmed in writing.

Free help while you complain

The Citizens Advice consumer service is the official source of free advice on energy problems and can refer urgent cases, such as a threatened disconnection or a vulnerable household left off supply, to its Extra Help Unit. Using it does not affect your right to go to the ombudsman.

Common questions

How long does my energy supplier have to resolve a complaint?

There is no fixed deadline for the supplier's answer, but after 8 weeks from your first complaint you can go to the Energy Ombudsman regardless, or sooner if the supplier issues a deadlock letter. Suppliers must signpost the ombudsman when either trigger is met.

Does complaining to Ofgem do anything?

Ofgem does not handle individual disputes, so a complaint sent to Ofgem will be redirected. It does use complaint data and can fine suppliers for widespread failures, so reporting patterns of poor behaviour has value, but your own remedy runs through the supplier and then the Energy Ombudsman.

What can the Energy Ombudsman award?

An apology, an explanation, practical action such as correcting a bill or removing an incorrect debt, and a financial award. Decisions are binding on the supplier once you accept them, but not binding on you, so rejecting a decision leaves court action open.

Can I be back-billed for old energy use?

Not beyond 12 months. If your supplier failed to bill you correctly and the failure was its fault, the back-billing rules prevent it charging for energy used more than 12 months before the corrected bill. Quote the back-billing principle explicitly in your complaint.

Track this complaint as you go

TrackMyComplaints comes with this exact stage structure as a ready-made template. Response deadlines are calculated in UK working days, and every letter, call and document stays on one timeline. Free, no card required.

Start tracking for free

Official sources

This guide is general information about complaint procedures in England, last reviewed 2026-07-16. It isn't legal advice; always check the organisation's own published policy.