Billing mistakes are one of the most common reasons UK households complain about their energy supplier. In most cases, the problem is not unusual or complicated. It usually falls into a small number of recognisable categories, and almost all issues can be spotted with your bill, a current meter reading, and ten minutes of patience.
This is a practical guide to how to spot errors on your energy bill. It is for anyone who has just received a bill that looks wrong, or who simply wants a methodical way to check it.
The most useful thing to do before anything else is to work out which kind of problem you have. A “wrong energy bill” can mean several very different things, and the fix depends entirely on which one it is.
First, work out which kind of problem you have
There are essentially three kinds of energy bill problem. Sort yours into one of these before contacting anyone.
Is it a direct debit problem? Your monthly direct debit is set too high or too low relative to what you are actually using. The bill itself may be correct. The issue is the amount the supplier is taking from your bank account each month. You can spot this if your account is building up a large credit balance, or sinking into a growing debit, while the underlying usage on the bills looks reasonable.
Is it a meter or meter reading problem? The bill is wrong because the readings driving it are wrong. Either the supplier is using estimates that have drifted from your actual usage, or the readings on file are incorrect, or the meter itself is faulty. This is the most common category by a wide margin.
Is it a bill problem? The readings and the direct debit are fine, but the bill itself contains an error. Wrong tariff applied, wrong standing charge, duplicate charges, or charges from before you moved in.
Once you know which bucket you are in, the rest of the page tells you exactly what to look for and what to do.
Direct debit problems
A direct debit is meant to spread the year evenly. Winter usage is much higher than summer, so the credit you build up in summer pays for the higher debit in winter. The supplier reviews the figure once or twice a year and adjusts it.
In practice the adjustment is often slow, sometimes wrong, and occasionally based on out-of-date usage forecasts.
Signs your direct debit is set too high:
- Your account is several hundred pounds in credit going into autumn
- The direct debit went up after a brief cold snap and never came back down
- You moved house and the new supplier set the direct debit using the previous occupant’s usage
Signs it is set too low:
- The credit balance never builds at all over summer
- Your statement keeps showing a growing debit despite paying on time
- You are heading towards a large catch-up bill at the next reading
How to fix: Submit an up-to-date meter reading, confirm your current balance, and use our direct debit fairness calculator to check what you’re paying is fair. Your supplier is allowed to refuse a reduction if they think the new figure will not cover winter, but you can challenge that, and you can request a refund of any excess credit beyond a reasonable buffer.
Meter and meter reading problems
This is where most energy bill mistakes hide. Several distinct issues sit inside this category, and they are worth understanding separately because the fixes differ.
Estimated readings that have drifted
Estimated readings are one of the biggest reasons energy bills go wrong. If your supplier has not received an actual meter reading for a long time, your bills may not reflect what you have really used. When the next real reading is submitted, you could face a large catch-up bill. In some cases this can be hundreds or even thousands of pounds. But it can also work in your favour. If your supplier has been overestimating your usage, you may be owed money instead.
Spot it by looking at the readings on the bill. Each one carries a small flag letter. “E” means estimated. “C” means you submitted it. “A” means actual, taken either by the supplier or by a working smart meter. A long run of “E” flags across recent bills is the warning sign.
How to Fix: take a reading now and submit it. Many disputes resolve themselves at this step, since a real reading replaces the guess. If the resulting catch-up bill goes back more than 12 months, the back-billing rule (covered further down) may protect you.
Disputed readings between old and new suppliers
If you have recently switched supplier, the open reading submitted to your new supplier and the closing reading used by your old supplier should match. They do not always. Sometimes the old supplier ignores the reading you submitted on switch day and estimates the close instead. Sometimes the new supplier rejects the reading as “implausible” and uses its own estimate.
The result of these discrepancies in readings is a gap. Energy you actually used either ends up double-billed, or vanishes from one account and resurfaces months later on the other.
Spot it by comparing the closing reading on your final bill from the old supplier against the opening reading on the first bill from the new supplier. They should be identical, or close to identical (a day or two of usage at most). A meaningful gap is your problem.
How to fix: send both suppliers the reading you took on switch day, with the date, and ask them to align the accounts. A photograph of the meter on the day, with a visible date, is the strongest evidence you can have.
Incorrect move-in or move-out readings
The same issue plays out at house moves. The reading the previous occupier (or your landlord, or the estate agent) gave the supplier on move-out day determines what you start paying for. If that reading is wrong, or if no one took one, you may end up being charged for energy the previous occupier used.
Spot it by comparing the meter reading on the day you moved in (taken from the meter itself, ideally with a dated photograph) against the opening reading on your first bill. If the bill’s opening reading is significantly lower than the actual meter reading on move-in day, you are being billed for someone else’s usage.
How to fix: send the supplier the move-in reading, dated proof of when you took occupancy (tenancy agreement or completion statement), and ask them to correct the opening balance. Do the same when you move out. Always take a final reading on the day you leave, photograph it, and submit it to the supplier in writing.
Erroneous transfers (the wrong supply has been switched)
An erroneous transfer is when the wrong supply gets taken over during a switch. Ofgem data suggests around 1% of switches end up as erroneous transfers, so they are not rare. They come in two flavours, and both are worth knowing about.
You did not ask to switch, but a supplier has taken you over anyway. Causes include a neighbour selecting the wrong address during sign-up, incorrect meter records on the national database (especially for flats, terraces, and new builds), or a broker entering the wrong MPAN or MPRN.
You did ask to switch, but the new supplier has taken over the wrong meter. This is the case worth slowing down on, because it is easy to miss. You completed a switch in good faith. A welcome pack arrived. Direct debits started going out. On the surface everything looks fine. But somewhere in the process, the supplier matched the switch to a different supply, often a neighbour’s meter, or the wrong meter in a building with several.
The clue is usually not in the bills themselves. It is in what your old supplier does, and in what numbers appear on the welcome pack.
How to check whether the right meter has been switched:
- Compare the MPAN (electricity) and MPRN (gas) on your new supplier’s welcome pack against the same numbers on your last bill from your old supplier. They should match exactly. If they do not, the new supplier has taken over a different supply.
- Compare the meter serial number on the new supplier’s welcome pack or first bill against the meter on your wall. Walk to the meter and read the serial number off the front of it. If it does not match what the new supplier has, they are billing you for someone else’s meter.
- Check what your old supplier is doing. After a normal switch, you should get one final bill from your old supplier within roughly six weeks, settling the account up to switch day. If your old supplier keeps sending you monthly bills as if you are still their customer, the switch never actually moved your supply. Someone else’s supply moved instead.
- Check what your new supplier is doing. If your first bill from the new supplier shows a meter reading and a serial number you do not recognise, or wildly different usage from what you have ever had, then the meter on their account may not yours.
- Take readings now, in writing, and date them. Whatever is happening, a current reading from the meter you are physically using is the strongest evidence you have. Photograph the meter showing the serial number and the current reading on the same image if possible.
How to fix: contact your new supplier (the one you switched to) first and tell them you suspect an erroneous transfer. Give them the MPAN, MPRN, and meter serial number you have physically read from the meter. Ask them to compare against the supply they have taken over. If the numbers do not match, they will need to reverse the transfer and switch the correct meter.
Also contact your old supplier, especially if they are still sending you bills, and let them know what is happening so the two of them can coordinate.
You should keep paying whichever supplier is actually supplying your property. In practice that is usually your old supplier until the error is corrected. You will not be left out of pocket. The two suppliers are required to put you back to the position you would have been in. The Erroneous Transfer Customer Charter, overseen by Ofgem, governs this process, and compensation may be payable if the suppliers miss the set timeframes for responding and resolving.
It can take several weeks to fully resolve, particularly in flats and new builds where the underlying database records often need to be corrected as well. Push for written confirmation at each stage, and keep a running thread of the correspondence.
Crossed meters (wrong meter serial number)
A crossed meter is where your supplier has the correct address, but the meter serial number on the bill does not match the meter physically on your wall. This could mean you are being billed for someone else’s meter, and they are being billed for yours. This is more common in flats, apartment blocks and new-build properties, where meter labels can sometimes be mixed up during installation, handover or supplier setup.
Spot it by walking to your meter and reading the serial number off the front of it. Then compare against the meter serial number printed on the bill. They should match exactly.
If they do not, that is a serious problem.
How to fix: contact your supplier and report a possible crossed meter. Ask them to log a “crossed meter investigation”. They will usually send an engineer to verify which meter belongs to which supply. Provide a photograph of your meter showing the serial number, the current reading, and the meter location.
Missed meter exchanges (MEX)
A missed meter exchange is where a meter has been physically replaced (usually a smart meter upgrade, or an old meter swapped for a new one) but the supplier’s system never recorded the change. Your account still references the old meter’s serial number and readings, even though that meter is no longer in the wall.
The symptoms are odd. Readings submitted from the new meter get rejected as “implausible” because the system is comparing them to readings from a different physical meter. Bills get stuck on estimates. Smart meter readings refuse to flow through to the account.
Spot it by checking the meter serial number on your bill against the meter actually installed. If you have had a meter swap in the last year or two and the bill still shows the old serial number, the exchange was probably never properly recorded.
How to fix: report it to the supplier and ask them to “update meter details on file” or “process the missed meter exchange”. You will need the serial number of the new meter, the date of installation if you have it, and a current reading. The supplier may also need the closing reading from the old meter, which the installer should have recorded.
Faulty meters
Genuinely faulty meters are rare but not impossible. Signs:
- Sudden unexplained jumps in usage with no change in what you do at home
- The dial or digits change when nothing is switched on
- Usage that is far higher than comparable households on similar tariffs
How to fix: contact the supplier. They will usually ask you to take daily readings for around a week first, to establish what your usage actually looks like. If that does not resolve it, you can request a meter accuracy test. The supplier may run their own test, or you can request an independent test through the Office for Product Safety and Standards, which contracts SGS (UK) Ltd to perform meter examinations under the Electricity Act 1989 and the Gas Act 1986.
The test itself is free. However your supplier may charge a fee for organising it and replacing the meter if the meter is found to be working correctly. Citizens Advice notes the fee is often around £200, but it varies by supplier (as of 2026; check with your supplier before requesting a test). Most meters tested turn out to be accurate, so the daily-reading step is worth doing first.
Bill problems
These are issues with the bill itself, not the meter or the direct debit.
Wrong tariff or unit rate applied. The unit rate on the bill is not the rate you signed up to, or it still reflects a fixed deal that has ended. Sense-check against your tariff documents and, if you are on a standard variable tariff, against the current Ofgem price cap. The price cap for 1 April to 30 June 2026 is £1,641 a year for a typical dual-fuel household paying by direct debit, with regional variation (as of April 2026; Ofgem reviews the cap every three months).
Incorrect standing charge. The daily charge should match your tariff and your region. Average direct debit standing charges under the Q2 2026 price cap are 57.2p a day for electricity and 29.1p a day for gas across Great Britain, with regional differences. A standing charge well above the regional figure is worth questioning.
Charges that pre-date your move-in. Covered above under move-in readings. If the bill covers a period before your tenancy or completion date, those charges are not yours.
Duplicate charges. Two bills overlapping on the same dates, or the same usage appearing twice. Common around tariff changes, supplier switches, or smart meter installations.
Maths errors. Rare on modern bills, but they happen. Multiply the unit rate by the kWh shown, add the standing charge for the days covered, add VAT at 5%, and see if you arrive at roughly the total on the bill. If you cannot, ask the supplier to break it down.
Common energy bill errors at a glance
| Type of problem | Category | How to spot it | What to do |
|---|---|---|---|
| Direct debit set too high | Direct debit | Account builds large credit going into winter | Submit a reading, ask supplier to reduce DD, request refund of excess credit |
| Estimated reading drift | Meter/reading | Long run of “E” flags on bills | Submit a current reading, ask for the bill to be reissued |
| Disputed switch readings | Meter/reading | Closing reading from old supplier does not match opening from new | Send both suppliers your switch-day reading with a dated photo |
| Incorrect move-in reading | Meter/reading | Bill’s opening reading does not match the meter on move-in day | Send move-in reading and proof of tenancy or completion date |
| Erroneous transfer | Meter/reading | Welcome pack from a supplier you did not sign up with | Contact your existing supplier; keep paying them as normal |
| Crossed meter | Meter/reading | Meter serial number on bill does not match meter on the wall | Raise a “crossed meter investigation” with the supplier |
| Missed meter exchange | Meter/reading | Bill still references old serial number after a meter swap | Ask supplier to record the meter exchange and update details |
| Faulty meter | Meter/reading | Sudden unexplained usage jumps, dials moving with nothing on | Daily readings for a week, then request a meter accuracy test |
| Wrong tariff or unit rate | Bill | Rate on bill not the rate you signed up to, or above regional cap | Quote your tariff details, ask for correction |
| Incorrect standing charge | Bill | Daily charge above your regional Ofgem cap figure | Query in writing, ask supplier to confirm correct rate |
| Duplicate charges | Bill | Same dates or readings appearing on two bills | Highlight overlap, request corrected statement |
What to do if you find an error
Submit a current meter reading first. This step alone resolves most estimate-driven disputes. If the supplier was guessing high, a real reading often clears the problem with no argument needed.
Contact your supplier in writing. Email, the app, or the supplier’s online message system. Not just a phone call. You want a record of what you said, when you said it, and what the supplier promised back. Quote the bill number and the specific charges or readings you are disputing.
Reference Ofgem’s back-billing rule where relevant. Under Ofgem’s back-billing rules, a domestic supplier cannot recover charges for energy used more than 12 months before a corrected bill is issued, if the failure to bill accurately was the supplier’s fault. The rule sits in Standard Licence Condition 21BA. If a catch-up bill suddenly lands covering two or three years of unbilled usage, you may be liable only for the most recent 12 months. The rule does not apply if you have acted unreasonably, for example by blocking access to the meter or ignoring requests for readings.
Know the 8-week threshold. If the supplier has not resolved your complaint after eight weeks, or has issued a deadlock letter before then, you can escalate the complaint free of charge to the Energy Ombudsman. The Ombudsman’s decision is binding on the supplier but not on you.
Get free help if you need it. Citizens Advice offers free, independent help at any stage. They have template letters, including one for back-billing disputes.
A note on estimated readings
This is worth re-emphasising, because it sits behind so many catch-up bill disasters.
Estimates exist for a reason. If there is no smart meter, or the smart meter has lost its connection, or no one has submitted a reading for a while, the supplier still has to issue bills. So it estimates. The problem is that forecasts drift, particularly over winter, when usage is heavier and the supplier is still extrapolating from summer figures. By the time an actual reading lands, the gap between billed usage and real usage can be substantial.
The fix is unglamorous. Submit a reading once a month if you do not have a working smart meter. Photograph the display. Keep the photos. If you have a smart meter that has gone offline (which happens to a meaningful share of installed meters), report it and push for a fix, since a smart meter that is not transmitting is no better than no smart meter at all.
A smart meter sending daily or half-hourly reads more or less eliminates this category of energy bill error.
When to escalate to the Energy Ombudsman or Citizens Advice
Two clear thresholds for going beyond your supplier.
Eight weeks without resolution. If you complained in writing and the supplier has not resolved the issue after eight weeks, you can take the complaint to the Energy Ombudsman free of charge.
A deadlock letter. If the supplier issues a deadlock letter before the eight weeks are up, stating that they cannot resolve the complaint further, that opens the door to the Ombudsman immediately.
The Ombudsman can order refunds, goodwill payments, apologies, account corrections, and other practical remedies. The decision binds the supplier. It does not bind you, so if you reject the outcome you keep your other legal options.
Citizens Advice is useful throughout, not just at the end. They offer free advice, can help you draft a complaint, and run the Extra Help Unit for vulnerable customers in more serious cases.
The Priority Services Register is also worth knowing about. If you are of pensionable age, have a chronic illness, a disability, mental health conditions, or other circumstances that make managing energy harder, you can register with your supplier for additional support, including help with reading meters and reading bills.
FAQ
How do I know if my energy bill is wrong?
Sort the problem into a category first. Is it your direct debit (the amount taken from your bank account), the readings driving the bill, or the bill itself? Then check the relevant things. For readings, compare your current meter reading against the closing reading on the bill, and look for long runs of “E” estimated flags. For the bill itself, compare unit rate and standing charge against your tariff and the current Ofgem price cap. For the direct debit, look at your credit balance against where you would expect to be at this point in the year.
What does “E” mean on my energy bill?
“E” means estimated. The supplier guessed the reading based on historic usage rather than reading the meter. A bill driven by repeated “E” readings is at high risk of being inaccurate. “C” means you submitted the reading yourself, and “A” means it was an actual reading taken by the supplier or sent by a working smart meter.
Can my energy supplier charge me for energy used more than a year ago?
Generally no, under Ofgem’s back-billing rules, if the failure to bill you accurately was the supplier’s fault. The rule applies to domestic customers and microbusinesses and sits in Standard Licence Condition 21BA. It does not apply if you blocked access to the meter, ignored requests for readings, or otherwise prevented the supplier from billing accurately. Back-billing also does not apply if you are still in credit after the corrected charges have been applied – this rule is to protect consumers from going into debit unfairly.
What is the back-billing rule?
The back-billing rule is a protection set by Ofgem. Where the supplier is at fault for not billing accurately, they cannot recover charges for energy used more than 12 months before the corrected bill is issued. It applies to every licensed energy supplier in Great Britain.
How do I dispute an energy bill in the UK?
Submit a current meter reading, then complain to your supplier in writing with the bill number and the specific charges in dispute. If they have not resolved it after eight weeks, or issue a deadlock letter, escalate to the Energy Ombudsman. Citizens Advice can help at any stage.
What is the Energy Ombudsman and when can I go to them?
The Energy Ombudsman is the free, independent body that resolves unresolved complaints between energy customers and suppliers. You can take a complaint to them once eight weeks have passed without resolution, or as soon as your supplier issues a deadlock letter. Their decisions are binding on the supplier.
My smart meter reading does not match my bill. What do I do?
Common, often because the smart meter has stopped transmitting and the supplier has been issuing estimates anyway. Take a manual reading from the meter itself, submit it in writing, and ask them to reissue the bill. If the meter is not transmitting, ask the supplier to investigate and either fix it or replace it. If you recently had a meter swap and the bill still shows the old serial number, you may be dealing with a missed meter exchange and should raise that specifically.
I have moved house and the bill includes charges from before I moved in. What now?
You are not liable for energy used before your tenancy start date or completion date. Send the supplier proof of your move-in date (tenancy agreement or completion statement) and the meter reading taken on the day you moved in. Ask them to correct the opening balance. If they refuse, raise a formal complaint, and escalate to the Ombudsman if it stays unresolved.
What is an erroneous transfer?
An erroneous transfer is when an energy supplier takes over the supply at your property by mistake, without your consent. Roughly 1% of switches are erroneous transfers, usually caused by an incorrect address selection or a mismatch between the meter and the national database. If it happens to you, contact your existing supplier immediately and keep paying them as normal. The two suppliers are required to sort it out between themselves, and you should not be left out of pocket.
My meter serial number does not match what is on the bill. What do I do?
Treat it seriously. It may be a crossed meter (you are being billed for someone else’s supply and vice versa) or a missed meter exchange (the supplier has not updated their records after a meter swap). Photograph the meter showing the serial number and current reading, contact the supplier, and ask them to log either a crossed meter investigation or a meter exchange update, depending on what has happened.
Why is my direct debit so much higher than my actual usage?
Suppliers set direct debits to spread the year evenly, but they sometimes get the forecast wrong, particularly after a price cap change or a house move. If you are several hundred pounds in credit going into winter, the direct debit is probably set too high. Submit a current reading and ask the supplier to reduce it. You can also request a refund of any credit beyond a reasonable buffer.
How accurate are estimated energy bills?
Often not very. Estimates are forecasts based on historic patterns, and they drift, especially over winter or after a change in household circumstances. Submitting a real reading at least once a month resolves the issue for most households. A smart meter sending daily or half-hourly reads removes the problem entirely.