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Back-Billing
Key takeaways
- Back-billing is when a supplier issues a bill for energy you used in the past but were never billed for.
- Ofgem’s back-billing principle generally limits suppliers from charging for energy used more than 12 months ago if the missed billing wasn’t the customer’s fault.
- It applies fully to domestic and microbusiness customers; larger businesses have weaker protection and should check their contract terms.
What is back-billing?
Back-billing is the practice of a supplier sending you a corrected or catch-up bill for energy you genuinely used but weren’t charged for at the time. This can happen after a meter exchange, a long run of estimated reads, or a billing system error.
Ofgem’s back-billing principle says suppliers should not seek payment for unbilled energy used more than 12 months before the corrected bill, as long as the customer hasn’t obstructed billing (e.g. blocked meter readings or refused access).
Who is protected
- Domestic customers — fully covered.
- Microbusinesses — covered.
- Larger businesses — protection depends on contract terms and any voluntary supplier policies; check the contract first.
What to do if you get a back-bill
Check whether the bill is for energy more than 12 months old and whether the issue was caused by missed actual readings or supplier error.
Ask the supplier to set out, in writing, how the unbilled period arose and why they think the back-billing protection does or doesn’t apply.
If you don’t agree, raise a formal complaint; after 8 weeks you can escalate to the Energy Ombudsman.
