Estimated energy bills are one of the most common sources of overpayment in UK households. When a supplier guesses your usage rather than measuring it, they can be out by hundreds of kilowatt-hours — and the error compounds over time. Here is exactly how to challenge an estimated bill and get your money back if you have been overcharged.

Why Estimated Bills Happen

Suppliers issue estimated bills when they have not received an actual meter reading. This happens because: a smart meter is not installed or not communicating correctly; you have not submitted a reading; an engineer was unable to access your meter; or there is a data transfer failure during a supplier switch. Ofgem’s rules require suppliers to use reasonable estimates based on your historical usage — but these estimates can diverge significantly from reality, especially after lifestyle changes.

How to Identify an Estimated Bill

Look for an E or the word Estimated next to the meter read on your bill. If you see actual reads listed but the consumption figures seem abnormally high or low compared to previous bills, request the underlying meter read data — you are entitled to it.

Step One: Submit an Actual Meter Reading Immediately

This is the most important step. Submit your current meter reading through your supplier’s app, website, or phone line. The supplier must issue a corrected bill based on actual data. If you have been overcharged, the difference appears as credit on your account — and you can request a refund.

Step Two: Request a Billing History Review

If you believe estimated reads have been building up over multiple billing periods — resulting in a large catch-up bill or accumulated overpayment — request a formal billing history review. Ask your supplier in writing to reconcile all estimated reads against actual reads from the past 12 months. Suppliers are required under Ofgem’s back-billing rule not to charge for energy used more than 12 months ago if the error was their fault.

Step Three: Escalate if Needed

If your supplier refuses to correct the bill or disputes your reading, log a formal complaint. This starts the 8-week regulated clock. If unresolved, the Energy Ombudsman handles disputes for free and their decisions are binding on suppliers. Keep all correspondence in writing — email is ideal as it creates a clear paper trail. Ready to cut your energy costs? Compare deals today.