What is Ofgem’s 12-month back-billing rule?

Ofgem’s back-billing rule generally means your energy supplier should not send you a new bill for energy used more than 12 months ago if the delay was the supplier’s fault (for example, they failed to bill you correctly). If you’re billed late in these circumstances, you may be able to challenge the charges and seek a correction or refund. Check your bill dates, account history and communications to confirm whether the rule applies.

When does the 12-month rule apply (and when doesn’t it)?

The back-billing protection is intended to apply when you have not been correctly billed due to supplier error. It may not apply if you prevented accurate billing (for example, refusing meter access where required, tampering, or persistently not providing meter readings when asked). Your circumstances matter, so compare the period being billed with what you did (and what the supplier did) during that time.

Can I get a refund if I’ve already paid a back-bill covering more than 12 months?

If you’ve paid charges for energy used more than 12 months before you were first correctly billed, and the delay was the supplier’s fault, you may be able to request a recalculation and refund (or account credit) for the out-of-time portion. Keep evidence such as bills, statements, meter readings and the date you received the corrected bill.

How do I check whether my bill includes back-billing beyond 12 months?

Look for the billing period (from/to dates) on the statement and identify when you were first correctly billed for that usage. If the supplier is charging for consumption older than 12 months from that date, note the affected dates and amounts. If you’re unsure, ask the supplier for a full statement of account showing the timeline of bills, readings and adjustments.

What should I do if I think my supplier has breached the back-billing rule?

Contact your supplier and raise a billing complaint, explaining that the bill includes charges older than 12 months and asking them to rebill in line with Ofgem’s back-billing rules. Request a written response and keep copies of all communications. If the issue isn’t resolved, you can escalate through the supplier’s complaints process and then to the Energy Ombudsman when eligible.

Does the 12-month rule apply to both gas and electricity?

Back-billing protections are generally associated with domestic energy supply and may apply to both gas and electricity where the supplier has failed to bill accurately. Exact applicability can depend on account type and circumstances, so review your supply details and the supplier’s explanation for the delayed billing.

How can Energy Plus help me switch and potentially reduce energy costs?

Energy Plus helps UK households compare energy options and switch suppliers. If you’re unhappy with billing issues or want a better deal, you can review your current tariff, compare alternatives and start a switch. Visit https://www.energyplus.co.uk/ to explore your options and check the latest guidance and tools.

Ofgem back-billing refund: the 12 month rule in the UK

Been hit with a surprise energy bill for months (or years) of usage? The Ofgem back-billing rules can limit what suppliers are allowed to charge. Check what the 12 month rule means, how refunds work, and compare whole-of-market tariffs to avoid bill shocks.

Understand when an energy supplier can’t bill you for older usage
Learn how to request a back-billing correction or refund
Compare whole-of-market home energy deals with EnergyPlus

Compare tariffs & cut your bills Check if the 12 month rule applies

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Compare whole-of-market home energy deals (and avoid bill shocks)

If you’re dealing with back-billing, you’re probably thinking about two things: putting the past right and preventing it happening again. Comparing tariffs can help you reduce monthly costs and choose a supplier with clear billing and meter-reading processes.

Tip: Even if a supplier must write off older charges under the Ofgem back-billing rules, you still want accurate bills going forward. Submitting regular meter readings (or ensuring your smart meter is communicating) can reduce the risk of estimated bills piling up.

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Already disputing a bill? Switching can still be possible, but don’t ignore supplier letters. Consider raising a formal complaint while you compare.

What is Ofgem’s back-billing 12 month rule?

In the UK, Ofgem’s back-billing rules (part of supplier licence conditions) are designed to protect households from being billed late due to a supplier’s failure to bill accurately or on time. In plain English: if your supplier didn’t bill you correctly, they generally can’t suddenly charge you for energy used more than 12 months ago.

What the rule covers

Late bills that arrive after a long gap
Catch-up bills after long periods of estimated readings
Corrections where the supplier failed to bill properly

What it doesn’t mean

It doesn’t automatically wipe all debt
It doesn’t apply if you prevented accurate billing (see exceptions)
It doesn’t remove your responsibility for the last 12 months of usage

Important: This page is guidance for UK households and is not legal advice. Your exact outcome depends on your billing history and supplier evidence (readings, account notes, smart meter data, and communications).

Why the 12 month back-billing rule matters (and how it can save you money)

Stops “shock bills”

If billing problems drag on, households can receive a huge catch-up bill. The rule limits how far back suppliers can charge when the delay is their fault.

Encourages accurate billing

Suppliers are expected to bill regularly and correctly. If they don’t, they may have to write off older unbilled usage—an incentive to fix issues quickly.

Helps you budget

When old charges are removed, you’re left with a clearer picture of what you actually owe for recent usage—and can set a realistic direct debit.

If your supplier recalculates your account and you end up in credit, ask about refund timing and whether your direct debit should be adjusted. Then compare tariffs to reduce future costs.

Does the Ofgem 12 month back-billing rule apply to you?

In many home-energy cases, the rule protects you if the supplier failed to send accurate bills. However, there are common exceptions—especially if the supplier can show the customer prevented accurate billing.

Likely covered (typical scenarios)

No bills (or clearly wrong bills) for long periods due to supplier errors
Supplier didn’t use available readings, or didn’t act on meter issues
Account set up incorrectly after moving home and supplier delays caused non-billing
Smart meter not communicating and supplier didn’t resolve it or bill accurately

Possible exceptions (supplier may still charge)

You blocked meter access repeatedly (where access was required)
You tampered with the meter or usage data (serious cases)
You didn’t take reasonable steps after being told your bills were wrong
You ignored requests for readings for a long time (depending on evidence)

Moving home? If you’re disputing charges from a previous address, gather your move-in/move-out dates, opening/closing readings, and tenancy documents. These can be crucial when the billing period spans multiple occupants.

How to request a back-billing correction or refund (step-by-step)

If you believe the supplier has billed you for energy used more than 12 months ago (and you didn’t prevent accurate billing), you can ask them to rework the account. Keep everything in writing where possible.

Check the dates on the bill
Identify the consumption period the supplier is charging for. Highlight any usage older than 12 months from the date they first issued a correct bill.
Gather evidence
Take current meter readings, find past readings, screenshots from your online account, and any messages where you asked for billing to be fixed.
Raise a formal complaint with the supplier
Ask them to apply Ofgem back-billing rules and to remove charges older than 12 months where the delay was their fault.
Ask for a corrected statement and repayment plan (if needed)
If you still owe for the most recent 12 months, request an affordable plan. If you’re in credit, request a refund and a direct debit review.
Escalate if unresolved
If the supplier doesn’t resolve it, follow their complaints process and consider escalation routes available to consumers (keep records and dates).

Quick checklist: what to include in your message

Account details
Name, supply address, account number, and the bill reference.

Timeline
When the issue started, what you were billed (or not billed), and any contacts you made.

What you want
Remove back-billed charges beyond 12 months, corrected statement, refund or revised plan.

Examples: when back-billing is (and isn’t) allowed

These simplified examples show how the 12 month rule can play out. Your supplier should explain their decision and provide a breakdown of charges and dates.

Scenario	What happened	Typical outcome
Estimated bills for 2+ years	Supplier didn’t use readings and then issued a large catch-up bill.	Charges older than 12 months may be written off if the delay was supplier fault.
Moved in, account not set up	You tried to open an account but billing didn’t start properly.	If you made reasonable attempts, older charges may be limited by the 12 month rule.
Supplier requested readings, none provided	Repeated requests were ignored and access was refused.	Supplier may argue the exception applies and back-billing could be allowed.
Smart meter not communicating	Supplier didn’t fix comms and didn’t bill accurately for a long time.	Often treated as supplier responsibility; older charges may be limited depending on evidence.

How refunds work: If your account is recalculated and you’ve overpaid (for example, due to incorrect estimated billing and a high direct debit), your supplier should update your balance. You can then request a refund of credit and/or a direct debit reduction—subject to any reasonable checks for upcoming seasonal usage.

Common mistakes that can weaken a back-billing complaint

Mistakes to avoid

Only discussing by phone and not keeping a written record
Focusing on the total amount, not the billing period and dates
Not providing a current meter reading when disputing usage
Missing move-in/out readings or tenancy evidence
Ignoring supplier letters—then being marked as unresponsive

Better approach

Set out a clear timeline and attach evidence
Ask for a corrected statement with date ranges
Request removal of charges older than 12 months where applicable
Confirm whether the supplier believes an exception applies—and why
Keep copies of emails, screenshots, and meter photos

FAQs: Ofgem back-billing refund and the 12 month rule

Can my supplier bill me for energy from more than 12 months ago?

Often, no—if the supplier failed to bill you correctly and you didn’t prevent accurate billing. But if the supplier can evidence an exception (for example, repeated refusal of access), they may still try to charge older usage.

Does the rule apply to prepayment meters?

Back-billing is typically discussed in the context of credit billing. If you’re on prepay, issues can still happen (for example, debt on the meter), but the facts can be different. If you’ve been moved between meter types, keep records and ask for a full breakdown.

If I’m due a refund, how long does it take?

It depends on the supplier and whether they need to complete account recalculations first. Ask for confirmation of your updated balance, the refund method, and whether they’re adjusting your direct debit to prevent overpayment continuing.

Can I switch supplier while disputing a back-billed amount?

Sometimes. Switching depends on your account status and the supplier’s processes. If you’re unsure, compare tariffs first and keep your complaint moving in parallel—don’t let deadlines slip.

What if the supplier says I “should have noticed”?

Ask them to explain, in writing, what steps they believe you failed to take and what evidence they have. Provide your own evidence of contacts you made and readings you supplied. The key question is whether you prevented accurate billing.

Will the rule reduce my current bills?

The rule is about historic charges. To reduce ongoing costs, compare tariffs, check your payment method, and ensure your meter readings are accurate. If you’re on an expensive standard variable tariff, switching can often help.

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Good to know: If your supplier is correcting historic billing, ask them to confirm the exact meter serial number and readings used. This can prevent “rebilling” problems from reappearing later.

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Updated on 24 Feb 2026