Your old energy supplier has ten working days to give your money back. Most people never ask.

What your old supplier owes you, and by when

Ofgem's Guaranteed Standards of Performance turn the timetable into money. Miss a standard and the supplier owes you £40 without being asked; the payment went up from £30 on 2 January 2025 to catch up with inflation. The two that matter most after a switch or a house move:

Ofgem's own summary, from the £240m press release: “Under Ofgem's Guaranteed Standards of Performance, suppliers must issue a final bill within 6 weeks and refund within 10 working days.” Citizens Advice adds the part suppliers rarely volunteer: they “must refund money left on your account no matter how long ago the account was closed.” A supplier that refunds late still owes the £40; it is not cancelled by paying up.

Why £240m is sitting there

Energy UK says more than 90% of closed-account balances go back automatically. The rest are stuck because the customer moved and never gave a forwarding address, so the final bill and the cheque went to the old house. Ofgem's Tim Jarvis put it plainly: “if you've moved in the last 5 years, reach out to your old supplier, provide them with the correct information, and you could be due a refund.”

Balances build up while you are a customer too. Ofgem's data for 2025 shows about 17 million fixed direct debit households in credit, holding an average total of £3.17bn, or £199 per household. That is your money earning the supplier interest. Ofgem's position is that you can “contact your supplier to claim this credit back at any time” and that suppliers “must do so promptly, unless there are reasonable grounds not to and they must explain to the customer why.” A 2021 proposal to force automatic refunds above a threshold was dropped, so nothing happens until you ask.

The bill they cannot send

Since May 2018 Ofgem has banned back-bills for energy used more than 12 months ago where the supplier is at fault: no accurate bill, no statement, or a direct debit it set too low. If a catch-up bill lands covering two or three years, the part older than 12 months is not payable, and a supplier that has already taken it owes it back. The exception is a customer who “acted unreasonably”, which Ofgem illustrates with refusing meter readings or tampering, not with simply paying what you were asked.

The free route

1. 1Find the account. Old bank statements show the supplier and the direct debit; your current supplier can look up who supplied the address on the industry database; a former landlord or flatmate may have the account number. The supplier can find you from name and old address alone.
2. 2Ask for the final bill and the refund in writing, with the two deadlines quoted: final bill within six weeks of the switch, refund within ten working days of the bill. Give the account number, the move or switch date and where to send the money.
3. 3Claim the £40s. If the final bill was late, or the refund was, say so and ask for the Guaranteed Standards payment for each. If they then pay the compensation late, that is another £40. Ask for interest earned on the balance too; Ofgem says suppliers should return it, though they are not required to.
4. 4If a back-bill covers more than 12 months, dispute the older part in the same letter and cite Ofgem's back-billing rules.
5. 5No reply or a refusal? Complain formally, wait eight weeks or get a deadlock letter, then go to the Energy Ombudsman within 12 months. It is free, it accepted 46,532 cases in the first half of 2026, and billing disputes were 58% of them.

FAQ