Energy Back-Bill: Do I Have to Pay for Energy Used Over 12 Months Ago?

The Rule

• When it applies: the supplier did not send an accurate bill, did not tell you about the charges through a statement of account, or set your Direct Debit too low.
• When it does not: if you acted unreasonably, for example blocking meter access, ignoring the supplier’s requests, or theft.
• This is for household customers. Business rules differ.
• You should still answer your supplier’s requests, such as giving meter readings.
• Energy Ombudsman: give the supplier 8 weeks, or until a deadlock letter if sooner. After a deadlock letter you have 12 months to go to the Ombudsman.

What to Do

1. Check the dates on the back-bill and what period it covers.
2. Gather your meter readings and past bills.
3. Write to the supplier, asking it to remove charges older than 12 months.
4. Ask for a complaint reference and a final response. Use the company guide for your supplier.

Ready-to-Use Letter or Email

Copy this, fill in the square brackets and send it in writing. Keep a copy and proof of sending.

Subject: Back-bill dated [date], account [number]

Dear [supplier],

I have received a bill of [amount] dated [date] covering [period]. Part of this relates to energy used more than 12 months before you told me about the charge. I understand that, under Ofgem rules, I should not be charged for that part where the supplier did not bill me accurately or tell me about the charges.

Please remove charges older than 12 months, confirm in writing, and pause any debt action while this is looked at. If you disagree, please send your final response so that I can go to the Energy Ombudsman.

Yours sincerely,
[Your name]

Related

• Energy company guides
• How long do I have to complain?

Sources

• Ofgem: what to do if you get a back bill
• Energy Ombudsman FAQs

Last checked 4 October 2026. Rules change, so check the official page before you rely on this. This is general information, not legal advice.