Business Energy Bill Errors: Have You Been Overcharged?

An unexpectedly high energy bill deserves a closer look. But a higher total does not, on its own, prove that your supplier has overcharged you.

The aim of a business energy bill check is to separate a calculation error, incorrect reading or contract discrepancy from a bill that correctly reflects your usage and agreed terms.

Start with the evidence—not the promise of a refund.

Why is my business energy bill so high?

First check whether the invoice uses estimated consumption and whether the meter details match your premises. Your supplier may need an up-to-date reading to reconcile an estimate. A credit note or replacement invoice also needs to be read alongside the original bill, rather than treated as an additional charge.¹

Next, check whether your previous contract ended. Deemed or out-of-contract terms can be more expensive, without the bill necessarily containing an error.²

A useful starting comparison is energy used, price charged and days billed—not just this month's total against last month's.

What should a business electricity bill check cover?

The site, meter and readings

Compare the supply address and meter serial number with the property and meter you actually use. Identify whether readings are actual or estimated. Where the figures do not reconcile, provide the supplier with dated evidence rather than assuming the meter is faulty.¹

The rates and contract dates

Put the invoice alongside your agreed contract and any valid variation notices. Compare the unit rate, standing charge, start date and end date. For a multi-rate electricity supply, compare the relevant day, night or weekend rates separately.

An invoice tells you what was charged. The contract and supporting documents help establish what should have been charged. Mark anything you cannot verify as an open question, not a confirmed overcharge.

The arithmetic and billing periods

Recalculate the consumption charge using kilowatt-hours multiplied by the relevant rate, and the standing charge using days multiplied by the daily charge. Check the treatment of overlapping dates against credit notes and replacement invoices.

For illustration, if an invoice incorrectly charges 1p/kWh more than the applicable agreed rate on 10,000 kWh, the difference is £100 before VAT. That calculation only establishes an overcharge after the applicable rate, volume and period have been verified.

VAT and Climate Change Levy

Ask whether the tax treatment is supported by the supply, usage, bill dates and any relevant certification. Do not assume that every business qualifies for reduced VAT or CCL relief.

CCL exclusions, exemptions and CCA reductions are different routes. Our Climate Change Levy guide explains the distinction and the evidence needed.³

How do I challenge a possible energy bill overcharge?

Send the supplier a focused query with the invoice number, disputed period, the specific discrepancy and the document or reading supporting it. Keep a copy of the evidence and the supplier's responses.

You can adapt this wording:

Please review invoice [number] for [billing dates]. The bill uses [rate or reading], while [contract or meter evidence] shows [value]. Please explain the difference and issue a corrected bill or credit if appropriate. Please also confirm how the disputed balance will be handled during your investigation.

Do not simply stop paying or cancel a Direct Debit without addressing the consequences with the supplier. The Energy Ombudsman advises keeping payments going during its process to avoid creating additional problems.⁴

What about old bills and unresolved complaints?

In Great Britain, Ofgem's back-billing protections can restrict certain charges for energy used more than 12 months earlier by microbusinesses. This is not a blanket rule cancelling every old business bill, and exceptions apply.⁵

Eligible microbusinesses and small businesses can take qualifying disputes to the Energy Ombudsman after eight weeks without resolution, or earlier following a deadlock letter. Check that your business and complaint fall within its remit.²⁴

Can I save money even if my bill is correct?

Yes, potentially—but that is a different question. A bill audit tests whether the existing charges are supported. A contract comparison tests whether another suitable offer would cost less on a consistent basis.

Keep those findings separate. An expensive but correctly billed contract is not automatically an energy bill error.

Check your electricity bill with Openlight

Upload your business electricity bill for an initial check of the figures and potential issues. Some checks need your contract, earlier bills, meter information or additional business details. A flagged issue is a reason to investigate, not a guaranteed refund.

Know what was checked, what needs evidence and what to do next.

Check my bill

Openlight's current online bill checker is electricity-only; this guide does not promise an automated gas or water audit.

Related guides: Save on CCL · Compare your next energy contract