Can your business be billed for energy used over a year ago?

Ofgem's back-billing rules protect microbusinesses from certain charges for energy used more than 12 months earlier where it was not accurately billed before. The protection has exceptions, including obstructive or unreasonable behaviour [S1]. Check your business classification, the consumption dates and earlier bills before challenging a demand. This guide covers Great Britain. Checked October 2026.

Last checked 17 October 2026

What counts as business energy back-billing?

A back bill seeks payment for energy already used that was not accurately charged before. It can follow a meter problem, an estimated bill or a billing error. The amount of the demand alone does not tell you whether the back-billing protection applies. [S1]

For a shop, pub or workshop, start by identifying the electricity or gas account and the periods being recovered. An unpaid bill issued correctly in the past is different from a newly calculated charge for old consumption. The rules do not erase an accurate bill simply because it remains unpaid. [S1]

Keep your contract, bills and statements together. Use how business electricity contracts work for the account terms and standing charges for the fixed daily component. This guide explains the Ofgem framework in Great Britain; do not assume it establishes your rights elsewhere.

Is your site a microbusiness for these rules?

The business back-billing protection applies to microbusiness consumers. Ofgem identifies consumption routes of up to 100,000 kilowatt-hours, or kWh, of electricity annually, or up to 293,000 kWh of gas annually. A kWh measures energy used. There is also a staff-and-financial-size route. [S2]

Ask your supplier to confirm which route it has applied to the account. Gather annual consumption records, and have your accountant check the alternative size test where needed. The classification for gas can differ from electricity, so do not assume the outcome for one fuel settles the other. [S5]

The broader small-business category for access to the Energy Ombudsman is a separate test. Having complaint rights does not establish that you have the microbusiness back-billing protection. Check both questions explicitly. [S5]

For a multi-site business, ask the supplier to explain which accounts and consumption it used in the assessment. Record the answer with your dispute rather than relying on a customer-service description of your organisation as simply a small business.

When does the 12-month limit protect your business?

Ofgem says you do not have to pay for energy used more than 12 months ago in the protected circumstances. These include not having received an accurate bill or a statement telling you what was owed, and a Direct Debit set too low to cover the charges. [S1]

Build a chronology showing when the supplier first sought the correct charges. Request the statements it relies on, not just the latest invoice. Ofgem’s charge-recovery guidance addresses previously unbilled consumption and explains the conditions and exceptions. A reissued invoice does not tell the whole account history. [S3]

Use this review table to prepare your questions:

The relevant checks come from Ofgem and the Energy Ombudsman’s explanation of back-billing. [S3], [S4]

When can the supplier still recover older charges?

Ofgem lists obstructive or unreasonable behaviour as an exception. Examples include blocking access to the meter, ignoring payment requests and stealing energy. Ask the supplier to identify the behaviour it alleges and the records supporting that position. [S1]

There is an important distinction between obstruction and simply not spotting an accumulating debt. Ofgem’s letter says suppliers remain responsible for accurate billing and should not hold customers responsible for failing to detect billing errors. It also says a failure to provide a meter reading does not itself remove the back-billing limit. [S3]

If the disputed period starts before you occupied the property, prepare the occupancy evidence separately. Use the change-of-tenancy checklist to assemble the handover records. Do not try to resolve an incorrect occupier account solely by arguing about the age of a bill. Check a contested liability question with your solicitor.

How do you challenge a retrospective business bill?

Write to the supplier through its complaints process. Identify the account, disputed periods and requested correction. Attach the evidence needed to explain the problem. The Energy Ombudsman recommends asking for the meter readings and a detailed charge breakdown. [S4]

A practical complaint file should contain:

• The new bill, earlier bills and account statements.
• Dated meter records, including the serial number and any exchange paperwork.
• Payment records matched to the account.
• Copies of readings submitted and earlier billing queries.
• The supplier’s explanation of your business classification.
• A short list of the corrections and documents you want.

Ask for an acknowledgement and complaint reference. Preserve each response with its date, and explain any new evidence against the original chronology. This makes the file usable if another person takes over the case.

Can your business take the dispute to the Energy Ombudsman?

Eligible microbusinesses and small businesses can ask the Energy Ombudsman to consider an unresolved supplier dispute after 8 weeks, or earlier following a deadlock letter, subject to its terms. The service checks its own eligibility requirements. Keep the complaint start date and final response in your file. [S5]

Ofgem monitors compliance but does not resolve individual supplier disputes. Follow the supplier’s complaint route, then the applicable escalation process. For an accurate balance you cannot afford, discuss payment support with the supplier as a separate issue. [S6], [S7]

What should you do next?

Return to the guide hub and business electricity data for context. Once the account is understood, use the cut-energy-costs goal and site check to plan operational improvements. Those tools do not determine a billing dispute.

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