Finding an error on your energy bill is frustrating and at today's prices, it can mean serious money. You are entitled to a full refund, plus statutory compensation, and Ofgem's rules back you every step of the way. This guide tells you exactly how to claim it.
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Quick Answer: Contact your supplier with evidence of the error. They must respond within 8 weeks. If they don't, take your complaint to the Energy Ombudsman. You can claim back overcharges, credit refunds, and up to £40 in statutory compensation for each missed standard. |
What Counts as an Energy Billing Error?
Your energy bill is calculated from meter readings multiplied by your unit rate, plus a standing charge. An error can happen at any stage of that process.
The 5 most common billing errors in the UK are:
• Estimated readings: Your supplier guesses usage instead of reading your meter. Repeated estimates compound over time.
• Wrong tariff applied: Charged at a rate you never agreed to, or a tariff change applied on the wrong date.
• Meter mis-association: Common in new-build flats, your address is linked to the wrong meter in the national database, so you pay for a neighbour's energy.
• Price cap overcharging: In 2026, Ofgem forced 10 suppliers to repay £7 million to 34,000 customers who were charged above the price cap due to multiple standing charges.
• Back-billing errors: A supplier sends a catch-up bill for energy used over a year ago, which Ofgem's back-billing rule may make unenforceable.
Know the 12-Month Back-Billing Rule
Your supplier cannot charge you for energy used more than 12 months ago if the under-billing was their fault. This protection covers both domestic consumers and microbusinesses.
The back-billing protection applies when:
• You never received an accurate bill, even after requesting one
• Your direct debit was set too low to cover actual charges
• No statement of account was sent to inform you of charges due
The rule does not apply if you:
• Blocked access to your meter
• Ignored payment requests or correspondence
• Tampered with or stole energy
For full details, see Ofgem's back-billing rules page.
Step 1: Gather Evidence Before You Call
Strong evidence makes your complaint harder to dismiss. Collect the following before contacting your supplier:
• Actual meter readings take a photo with a date stamp
• Recent bills showing the disputed charges
• Records of any readings you submitted previously
• Correspondence confirming your tariff rate
• Bank statements showing direct debit amounts
If you have a smart meter, your half-hourly consumption data is downloadable from your online account. This is the strongest evidence you can produce.
Step 2: Contact Your Supplier Formally
Call or write to your supplier and state clearly: which bill or charges you are disputing, the specific amount, and the evidence you hold. Keep these details on record:
• Date and time of every call
• Name of the agent you spoke to
• Reference number given for your complaint
Follow up every phone call with a written email; email is fine. Your supplier must respond within 8 weeks. Use your account number (shown at the top of your bill) on every communication.
If you are disputing a back-bill, use the Citizens Advice back-billing example letter as a template.
Step 3: Know Exactly What Compensation You Are Owed
Since 2 January 2026, Ofgem's Guaranteed Standards of Performance (GSoP) payments increased from £30 to £40 per breach.
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Supplier Failure |
Compensation (from Jan 2026) |
Payment Deadline |
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No final bill within 6 weeks of switching |
£40 |
10 working days |
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Credit balance not refunded within 10 working days |
£40 |
Further 10 working days |
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Missed engineer's appointment |
£40 |
10 working days |
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Switch delayed beyond 5 working days |
£40 |
10 working days after the switch |
You can claim back credit balances at any time, regardless of how long ago your account was closed. Suppliers must also refund the credit balance on a live account if you request it see Ofgem's credit refund guidance for full details.
Step 4: Escalate to the Energy Ombudsman
Contact the Energy Ombudsman if your supplier has not resolved the complaint within 8 weeks, or if you receive a deadlock letter stating no agreement can be reached.
The Energy Ombudsman can:
• Force your supplier to reconsider or respond to your complaint
• Award financial compensation of up to £10,000 in appropriate cases
• Order a specific action, such as correcting your account
You must refer your complaint within:
• 12 months of receiving your supplier's final decision, or
• 9 months after the initial 8-week complaint period, if you have received no decision
Submit your case via the Energy Ombudsman website, by phone, or by post. The service is free.
Step 5: Dealing with a Back-Bill from Your Supplier
A back-bill (sometimes called a catch-up bill) arrives when your supplier has undercharged you and wants to recover the difference. Do not pay immediately; check whether the 12-month back-billing rule applies first.
Write to your supplier and state that you believe the charges fall outside the 12-month window. For businesses, suppliers must offer a payment plan of the same length as the original billing period to help spread the cost.
If your supplier disputes this, contact Citizens Advice for free, confidential guidance.
What About Overcharging Above the Energy Price Cap?
The energy price cap sets a maximum unit rate suppliers can charge. Any charge above the cap is automatically an overcharging error, and you are entitled to a full refund of the excess plus a goodwill payment.
In 2026, Ofgem secured £7 million in refunds from 10 suppliers who had overcharged customers with multiple electricity meters. The average refund was £206 per household. If you suspect your standing charge or unit rate exceeds the cap, use Ofgem's price cap checker to verify, then raise a formal complaint.
To understand how the current cap affects your bill, see our energy price cap guide.
How to Prevent Future Billing Errors
Submit Meter Readings Every Month
If you do not have a smart meter, submit a reading every month, not just when prompted. Monthly readings eliminate estimated bills and prevent credit or debt from building up silently over time.
Get a Smart Meter Installed
Smart meters transmit readings automatically, removing estimated billing entirely. Over 70% of UK households had one by September 2026. Request installation from your supplier it is free. Find out more from Smart Energy GB.
Check Your Meter Association When Moving
When moving into a new property, verify that the meter numbers registered to your address are correct before your first bill arrives. This is especially important in flats. Provide both opening and closing meter readings, and update your contact details immediately.
Switch to a Better Deal if You Are Overpaying
Billing errors are sometimes a sign that your tariff no longer represents good value. Compare home energy deals on Switch Squid to see whether switching saves money. Our comparison covers all major UK suppliers, including British Gas, EDF, E.ON Next, and ScottishPower.
Getting Financial Support While Your Dispute Runs
Disputing a bill does not mean you stop paying altogether. Overpaying can occur while you wait for a resolution. Here are 3 options:
• 1. Payment plan: Ask your supplier to freeze or reduce your direct debit while the dispute is investigated.
• 2. Warm Home Discount: Check eligibility on GOV.In the UK, if you are on a low income, this is a £150 annual rebate applied directly to your bill.
• 3. Citizens Advice Extra Help Unit: If you are in a vulnerable situation, call 0808 223 1133 for case-by-case support from trained advisers.
For business customers with back-billing disputes, see our business energy guide for additional options.
Frequently Asked Questions
1. How long does an energy supplier have to respond to a billing complaint?
8 weeks. Your supplier must respond within 8 weeks. If they do not, or send a deadlock letter, you can escalate to the Energy Ombudsman immediately.
2. Can I get compensation if I was overcharged on my energy bill?
Yes. You are entitled to a full refund of any overcharge. If your supplier also breached a GSoP standard such as failing to refund a credit balance within 10 working days you are owed an additional £40 (from January 2026) on top of the refund.
3. What is the 12-month back-billing rule?
Ofgem's back-billing rule prevents suppliers from charging you for energy used more than 12 months ago, provided the under-billing was the supplier's fault and you acted reasonably throughout.
4. How much can the Energy Ombudsman award?
Up to £10,000. The Ombudsman can award financial compensation in appropriate cases, though most awards are significantly lower. The service is free and independent.
5. My energy bill is estimated is that an error?
Not automatically. Estimated bills are legal, but they become an error when estimates are consistently wrong over time. Submit an actual meter reading and your supplier must issue a corrected bill within 5 working days.
6. Can I claim back a credit balance from a closed energy account?
Yes, at any time. There is no time limit on claiming credit from a closed account. Contact your old supplier with your previous address and account number. If they fail to refund within 10 working days, you are owed £40 in GSoP compensation.
7. What if my energy meter is faulty?
Request a meter accuracy test from your supplier. If the meter is found to be faulty, your supplier must recalculate all affected bills and refund any overcharge. Take photos of the meter regularly as supporting evidence.
8. I think I'm being charged for the wrong address. What do I do?
This is a meter mis-association error. Contact your supplier immediately with your address and meter serial number. If they cannot resolve it, contact Ofgem or the Energy Ombudsman. This error is common in newly built blocks of flats.
9. Do the back-billing rules apply to businesses?
Yes. Ofgem's back-billing rules apply to both domestic consumers and microbusinesses. A microbusiness is defined as one with fewer than 10 employees or annual consumption below 100,000 kWh for gas or 55,000 kWh for electricity.
10. Should I switch suppliers if I keep getting billing errors?
Persistent billing errors, especially estimated bills, are a strong signal that your current supplier is not managing your account properly. Compare energy deals on Switch Squid to find a supplier with better service ratings, or explore dual fuel options for a simpler, single-bill arrangement.
Summary
Billing errors cost UK households millions of pounds each year, but the rules are firmly on your side. Identify the error, gather evidence, contact your supplier formally, and escalate to the Energy Ombudsman if needed. The 12-month back-billing rule, GSoP compensation payments of £40 per breach, and the Ombudsman's power to award up to £10,000 all exist to protect you.
Once the dispute is resolved, use it as a prompt to review your tariff. Compare home energy deals or check business energy rates on Switch Squid to make sure you are on the best deal going forward.