Ofgem backbilling rules could unlock refunds for thousands of households

Ofgem’s backbilling rules will force energy suppliers to refund thousands of households for charges dating back more than 12 months. The regulator confirmed the guidance to North Wales Live last week, closing a loophole that left some customers paying for energy they used years ago.

As reported by North Wales Live, the rules apply to all domestic customers on standard variable or fixed tariffs. The catch is that suppliers can still bill beyond 12 months if you prevented a meter reading or acted fraudulently. For most households, though, the clock starts ticking from the date the energy was used.

Who qualifies — and who doesn’t

The rule covers any energy used more than 12 months before the supplier issued the bill. If you received a shock demand for electricity or gas from 2022 in 2024, you can challenge it. Ofgem’s guidance, updated in March 2025, makes clear that suppliers must write off the debt and refund any overpayment within 10 working days.

Exceptions exist. If you refused access for a meter reading, tampered with the meter, or delayed providing accurate readings, the supplier can bill for older usage. The burden of proof lies with the supplier, not the household. Citizens Advice reported last year that one in five backbilling complaints involved bills over two years old, with an average disputed amount of £340.

What it costs a typical 3-bed semi

For a household using 12,000 kWh of gas and 3,000 kWh of electricity annually, a backbilled amount of £340 represents roughly 15% of the annual bill at current price cap levels. That sum, if refunded, could cover the deposit for a heat pump installation under the Boiler Upgrade Scheme or pay for loft insulation across a standard 50 m² attic.

The Energy Saving Trust estimates loft insulation alone can save a typical semi-detached home £355 per year on heating bills. A backbilling refund of £340 would essentially pay for itself within 12 months of installation. Solar panel systems, costing around £5,000-£6,000 for a 4 kW array, require bigger sums, but every refund helps reduce the upfront barrier.

How to check and claim

Start by gathering your energy bills for the past two years. Look for any charges that reference usage before the bill date. Suppliers are required to include the billing period on each statement. If you find a charge for energy used more than 12 months ago, write to your supplier citing Ofgem’s backbilling rules.

Ofgem’s website includes a template letter for disputes. The supplier must respond within eight weeks. If they reject the claim, you can escalate to the Energy Ombudsman. The process is free and does not require a solicitor. Households on prepayment meters should check their online accounts for historical charges, though the rules technically apply to all payment types.

But the rules only cover usage older than 12 months. If your supplier billed you for energy used 11 months ago, you must pay. The key is timing: the 12-month window runs from the date of consumption, not the date you received the bill. Suppliers who deliberately delay billing to avoid the rule face fines of up to 10% of annual turnover under Ofgem’s enforcement powers.

Households with smart meters should have accurate records, but even they can fall victim to billing errors. Ofgem’s data from 2024 shows that one in three smart meter users still received estimated bills, increasing the risk of backbilling. Check your online portal for actual vs estimated readings. If your supplier used estimates for more than 12 months, you may have grounds for a refund.

Act before 31 March 2027, when the current price cap period ends. After that, Ofgem may revise the rules. For now, the refund route is open. Write to your supplier this week. The money could be in your account within a fortnight.