Energy bill errors are more common than most organisations realise. Studies suggest that between 10% and 25% of commercial energy invoices contain at least one error. For a portfolio spending £1M per year on energy, that could represent £100,000 or more in overpayments — most of which goes unrecovered.
This guide explains what bill validation is, what errors it catches, and how to build a validation process that works.
What is energy bill validation?
Bill validation is the process of checking an energy invoice against the contract, the meter data, and the relevant tariff structure to confirm that what you've been charged is what you should have been charged.
It sounds simple. In practice, energy invoices are complex documents with many moving parts — and energy suppliers make mistakes.
The most common billing errors
1. Incorrect unit rates
Your contract specifies the rate you pay per kWh. If the supplier applies a different rate — even by a fraction of a penny — and your consumption is high, the difference adds up quickly.
How to check: Compare the unit rates on the invoice against the rates in your contract documentation.
2. Wrong standing charges
Standing charges (daily supply charges) are fixed amounts independent of consumption. They're easy to set incorrectly on supplier systems and easy to overlook on invoices.
How to check: Confirm the daily pence charge matches your contract for each supply point.
3. Estimated vs actual read reconciliation
When a supplier estimates a meter read, they issue an estimated invoice. When an actual read is taken, they issue an adjusted invoice. Errors arise when:
- The reconciliation period is wrong
- The adjustment is applied to the wrong invoice
- The estimated read was so far from actual that the reconciliation itself has errors
How to check: Trace the read history for each meter and confirm that estimated invoices have been correctly reconciled.
4. VAT and CCL errors
Commercial energy supplies are generally subject to 20% VAT and the Climate Change Levy (CCL). Organisations with de minimis business use may be entitled to the reduced 5% VAT rate. CCL rates change annually.
How to check: Confirm VAT rate is correct for your use type, and that CCL rates match the current published schedule.
5. Duplicate invoices
The same invoice, or the same charge period, appearing twice. More common than you might expect, particularly around period-end.
How to check: Maintain an invoice register and check each new invoice against it.
6. Capacity and demand charges
For half-hourly metered supplies, capacity charges (kVA) and excess capacity charges are based on your peak demand. These are complex to check and frequently wrong.
How to check: Requires HH consumption data and your capacity agreement details.
How to build a validation process
A robust bill validation process has three components:
1. Data: You need meter read data (ideally automated) and a copy of your contracted tariff for each supply point. Without both, you can't check the invoice.
2. Checks: A systematic set of checks applied to every invoice: unit rates, standing charges, read reconciliation, VAT, CCL, duplicate detection.
3. Dispute management: A process for raising disputes with suppliers, tracking credits, and reconciling them against future invoices.
For a small portfolio, this can be done manually with the right spreadsheets. For anything above 20–30 supply points, automation is essential.
Recovering what you're owed
When you identify an error, you're entitled to a credit or refund. The process:
- Document the error with evidence (invoice, tariff schedule, meter data)
- Raise a formal dispute with your supplier
- Suppliers typically have 30 days to respond
- If the error is confirmed, a credit note is issued against a future invoice
- Track the credit to ensure it's applied correctly
Most suppliers will go back 12 months to reconcile errors. Some contract terms allow you to go back further.
Automated bill validation
Manual validation is time-consuming and inconsistent. Automated validation applies the same checks to every invoice, every time, in seconds.
Etainabl's validation engine runs more than 200 checks on every invoice it receives. Errors are flagged with supporting evidence, ready for your review. Disputes are tracked through to resolution.
See how bill validation works in Etainabl or book a demo to see it on your own data.