How to Dispute an Energy Bill UK 2026

If you have received an energy bill that looks too high, you are not alone. Ofgem data shows that millions of UK households contact their energy supplier about billing issues every year. The good news is that you have clear legal rights as a consumer, and there is a structured process for challenging unfair bills.

This guide covers every step of disputing an energy bill in the UK in 2026, from checking your bill for errors to escalating to the Energy Ombudsman if your supplier refuses to help.

Step 1: Check your bill for errors

Before contacting your supplier, check these common causes of unexpectedly high bills:

• Estimated readings: If your bill says “estimated” (often marked with an “E”), your supplier has guessed your usage rather than reading your meter. Submit an actual meter reading through your supplier's app or website — this alone often corrects overcharges.
• Billing period overlap: Check whether you are being billed for a period you have already paid for, especially if you have recently switched suppliers.
• Wrong tariff: Confirm you are on the tariff you agreed to. Suppliers sometimes move customers to default (more expensive) tariffs when a fixed deal expires.
• Smart meter problems: Smart meters can occasionally send incorrect readings, particularly after switching suppliers. If your smart meter shows different figures to your bill, flag this immediately.
• Back-billing: If your supplier is suddenly billing you for months or years of past usage, the back-billing rules may apply (see below).

Step 2: Understand your rights

As a UK energy customer, you are protected by several layers of regulation:

Ofgem Supplier Licence Conditions

Every licensed energy supplier in the UK must comply with Ofgem's supplier licence conditions. These include obligations around billing accuracy, providing clear information, and treating customers fairly. If your supplier has issued an incorrect bill, they are potentially in breach of their licence conditions.

The back-billing rule (12-month cap)

Under Ofgem's back-billing rules, your energy supplier cannot charge you for energy used more than 12 months ago if the supplier was at fault for not billing you correctly. This is one of the most powerful consumer protections in energy regulation.

This rule applies when: the supplier failed to send bills, failed to read your meter, failed to act on readings you provided, or made errors in their systems that led to incorrect or missing bills. It does not apply if you deliberately obstructed meter readings or tampered with your meter.

Consumer Rights Act 2015

The Consumer Rights Act 2015 gives you statutory rights when buying services, including energy. Services must be provided with reasonable care and skill, and at a reasonable price. If your bill is demonstrably unreasonable compared to your actual usage, the CRA provides additional grounds for your complaint.

Standards of Conduct

Ofgem requires all suppliers to treat customers fairly and provide clear, accurate information. The Standards of Conduct are enforceable, and suppliers who breach them face Ofgem enforcement action.

Step 3: Contact your supplier

Your first step is always to complain directly to your energy supplier. Do this in writing — email or letter — so you have a record. Your complaint should include:

• Your account number and property address
• The specific bill or billing period you are disputing
• A clear explanation of why you believe the bill is wrong
• Any evidence you have (meter readings, photos of your meter, previous bills showing lower usage)
• The specific regulations you believe have been breached (Ofgem licence conditions, back-billing rules, Consumer Rights Act)
• What you want them to do — recalculate the bill, issue a credit, or cancel the disputed amount

Keep a copy of everything. Your supplier is required to acknowledge your complaint and provide a response. If they do not resolve it to your satisfaction, the next step is escalation.

Step 4: Escalate to the Energy Ombudsman

If your supplier has not resolved your complaint within 8 weeks, or has issued a “deadlock letter” saying they cannot help further, you can escalate to the Energy Ombudsman for free.

The Energy Ombudsman can:

• Order your supplier to apologise, explain what went wrong, and take corrective action
• Award financial compensation (typically £50 to £500, depending on the impact)
• Require the supplier to recalculate your bill, issue a credit, or write off disputed charges

The Ombudsman's decision is binding on the supplier (though not on you). If you are not satisfied with the Ombudsman's decision, you can still pursue the matter through the courts, though this is rarely necessary.

How long does the process take?

• Supplier response: Most suppliers respond within 1-4 weeks
• 8-week escalation window: If unresolved after 8 weeks, you can go to the Ombudsman
• Ombudsman decision: Typically 6-8 weeks after you submit your case

The total process can take 2-4 months, which is why it is important to start your formal complaint as early as possible. The sooner you write to your supplier, the sooner the 8-week clock starts.

Tips for a successful dispute

• Always complain in writing: Phone calls are harder to evidence. An email or letter creates a permanent record.
• Cite specific regulations: Mentioning Ofgem licence conditions, the back-billing rule, or the Consumer Rights Act shows your supplier you know your rights.
• Include evidence: Meter readings, photos, previous bills, and bank statements showing direct debits all strengthen your case.
• State the 8-week escalation right: Mentioning the Energy Ombudsman in your initial complaint often motivates a faster resolution.
• Keep paying what you think is fair: Continue paying an amount you consider reasonable while the dispute is ongoing. This shows good faith and prevents your supplier from taking debt recovery action.