Business energy complaints follow a two-stage process. First, raise the complaint formally with the supplier and allow up to 8 weeks for resolution. If unresolved at that point, microbusiness customers can refer to the Energy Ombudsman. Larger businesses do not have Ombudsman access and must pursue civil routes. The Ombudsman can award financial remedies, direct supplier action, and require formal apologies.
Last reviewed: 12 May 2026
Why the Process Matters More Than the Complaint Itself
Many businesses with legitimate energy complaints fail to recover anything because they do not follow the formal process. A phone call to customer services, a complaint not put in writing, or an escalation made too early or too late can all result in a complaint being rejected or delayed without a substantive outcome.
Ofgem's Standard Licence Conditions impose specific obligations on suppliers regarding complaint handling. The process has defined stages and timelines. Understanding them before raising a complaint is the difference between an outcome and an extended frustration.
This guide covers the formal stages in order, from first contact through to Ombudsman referral or civil litigation for larger businesses.
Stage 1: The Internal Complaint
The complaints process starts with a formal complaint to the supplier. This must be in writing to create a clear record with a dateable start point. Email is preferable to letter for this purpose: it provides a timestamp, a delivery record, and a searchable reference.
The complaint should include:
- Your account number and supply point reference (MPAN or MPRN)
- A clear description of the issue: what happened, when it happened, and what resolution you are seeking
- Copies of any relevant invoices, correspondence, or photographs
- A request for written acknowledgement of the complaint
Do not use a general customer services email for a formal complaint. Most suppliers have a specific complaints contact. Check the supplier's website for the dedicated complaints address or department. If the supplier's published complaints contact is only a phone number, send a follow-up email after the call confirming what was discussed and that you are making a formal complaint.
The 8-Week Deadlock Rule
Ofgem's Standard Licence Conditions on complaint handling require suppliers to attempt to resolve complaints within 8 weeks. Two outcomes can trigger access to the Ombudsman before that period expires:
Deadlock letter: The supplier issues a written statement confirming the complaint cannot be resolved internally. Once this letter is received, the complaint can immediately be referred to the Ombudsman.
8-week passage without resolution: If 8 weeks pass from the date of the formal complaint without a resolution being agreed, the complaint can be referred to the Ombudsman without waiting for a deadlock letter.
In practice, many suppliers issue deadlock letters well before 8 weeks where the complaint involves a clear regulatory question (such as a back-billing dispute under SLC 21B) and the supplier's position is fixed. Accepting a deadlock letter does not mean accepting the supplier's position; it simply opens the Ombudsman route.
Keep a record of all correspondence with dates. If the supplier disputes when the formal complaint was received, your email timestamps provide the evidence.
Stage 2: Who Can Access the Energy Ombudsman
Access to the Energy Ombudsman (Ombudsman Services: Energy) is restricted by customer category. Domestic customers and microbusiness customers can refer complaints once deadlock is reached. Larger non-domestic customers cannot.
Microbusiness eligibility follows the Ofgem definition: consumption below 100,000 kWh electricity or 293,000 kWh gas per year, or fewer than 10 employees with turnover or balance sheet below 2 million euros.
If your business is close to the microbusiness threshold, confirm your eligibility before making the referral. The Ombudsman will ask for evidence of your consumption and business size as part of the intake process. If your complaint relates to a period when you were a microbusiness but you have since grown above the threshold, you may still qualify for the period in question.
What to Include in the Ombudsman Referral
The Ombudsman's investigation is document-driven. The quality of the evidence submitted at referral determines how quickly the investigation progresses and how strong your position is. Include the following in the initial referral:
Chronological complaint summary: A concise timeline of events from the first billing error or incident through to deadlock. Keep this factual and date-specific.
Copies of all written correspondence with the supplier: Including the initial complaint, any supplier responses, and the deadlock letter.
Relevant invoices: Highlighting the specific charges or errors in dispute.
Supporting documents: Meter read photographs, contract documentation, meter read submission confirmation emails, or any other evidence relevant to the dispute.
The outcome you are seeking: State clearly what resolution you want: a refund, a corrected bill, a formal apology, or a combination.
The Ombudsman does not hold hearings. The investigation is conducted on the written record. Submitting a clear, organised evidence pack accelerates the process.
Typical Ombudsman Timelines and Award Types
The Ombudsman's investigation typically takes 6 to 12 weeks from the date of referral, depending on the complexity of the complaint and the supplier's responsiveness. Simple billing disputes may be resolved faster; complex cases involving multiple periods of estimated billing or disputed meter reads may take longer.
The Ombudsman can issue the following remedies:
Financial remedy: A payment to the customer, either a refund of overcharged amounts or a goodwill payment where the supplier's conduct caused inconvenience or distress. The Ombudsman can award up to £10,000 for energy complaints, though the majority of awards for billing disputes are under £500.
Supplier action: A direction to the supplier to take a specific step, such as issuing a corrected invoice, resetting a tariff to the correct rate, or updating account records.
Formal apology: Where the supplier's handling of the complaint fell below the standard required by Ofgem's licence conditions.
The Ombudsman's decision is presented to the customer as a proposed resolution. If the customer accepts it, the decision becomes binding on the supplier. The supplier must implement the remedy within 28 days. If the customer rejects the Ombudsman's proposed resolution, the complaint is closed and the customer retains the right to pursue civil litigation.
Routes for Larger Businesses Without Ombudsman Access
Businesses above the microbusiness threshold that reach deadlock with their supplier have no access to the Ombudsman scheme. Their options are:
Dispute resolution clause in the supply contract: Some commercial energy contracts include a specific dispute resolution mechanism, such as mediation or expert determination. Check the contract terms before assuming litigation is the only route.
Small Claims Court: For disputed amounts up to £10,000 in England and Wales (£5,000 in Scotland), the small claims track is accessible without legal representation. The process is slower than the Ombudsman but does not require specialist energy knowledge from the business.
Civil litigation: For larger amounts, instructing a solicitor and issuing proceedings in the county court or high court. The economics of litigation need to justify the legal costs, which limits this route to disputes involving significant sums.
Citizens Advice Business Debt Line and Energy Helpline: Can provide guidance on options for non-microbusiness customers and may be able to assist with drafting formal correspondence.
Common Complaint Types and Expected Outcomes
Estimated billing disputes: Where a supplier has run estimated reads for an extended period and issued a large back-bill on obtaining an actual read. Microbusiness customers can invoke the 12-month back-billing rule (SLC 21B). Expected outcome: write-off of charges beyond the 12-month window plus potential goodwill payment.
Incorrect tariff or rate applied: Where the unit rate on invoices does not match the contracted rate. Expected outcome: recalculation of all affected invoices and refund of the difference.
VAT rate errors: Where 20 per cent has been applied when 5 per cent should apply. Expected outcome: credit note for the VAT difference.
CCL incorrectly charged: Where CCL has been applied despite an exemption. Expected outcome: credit note plus potential interest where the supplier delayed correction.
Contract auto-renewal at worse terms: Where a supplier renewed a contract at a significantly higher rate without adequate notice. Expected outcome depends on the specific licence conditions applicable and the terms of the original contract.
Frequently asked questions
Editorial disclaimer: This information is provided for general guidance only. For specific complaint strategies, consider contacting Citizens Advice or an independent energy adviser before escalating to the Ombudsman.
Can I go to the Ombudsman before 8 weeks if the supplier refuses to engage?
Not ordinarily. The Ombudsman requires either a deadlock letter or the passage of 8 weeks from the formal complaint date. If the supplier is not responding, document your attempts to make contact and cite the lack of response as evidence when you do refer.
Is there a fee to use the Energy Ombudsman?
No. The Ombudsman service is free to complainants. Suppliers fund the scheme through annual fees.
What if the Ombudsman finds in the supplier's favour?
If the proposed resolution does not uphold your complaint, you can reject it. This does not prevent you from pursuing the matter through civil litigation if the amount justifies it.
How do I find the correct formal complaints contact for my supplier?
Check the supplier's website under the Complaints section. Ofgem's licence conditions require suppliers to publish their complaints procedure. If not accessible online, request it in writing from your account manager.
Can the Ombudsman award compensation for business losses caused by a billing error?
The Ombudsman can award financial remedies for direct losses and for inconvenience caused by the complaint handling, but is not a court and cannot award consequential business losses. For larger consequential claims, civil litigation is the appropriate route.
How we verified this
This article draws on published guidance from Ofgem, the Department for Energy Security and Net Zero, and the primary legislation and regulatory sources listed in the Sources section. No aggregator or supplier-produced content was used as a primary source.
Sources
- https://www.ofgem.gov.uk/licences-industry-codes-and-standards/licences/licence-conditions
- https://www.ombudsman-services.org/sectors/energy
- https://www.ofgem.gov.uk/consumers/business/micro-business
- https://www.citizensadvice.org.uk/consumer/energy/energy-supply/problems-with-your-energy-supplier/complain-about-your-energy-supplier/
