Energy back billing errors: how to deal with an unexpected bill

Last updated: 29 January 2021

In this guide you’ll receive answers to the following questions:

  • What is back billing? 

  • Why did I get charged for an old electricity bill? 

  • Are there any back billing rules? 

  • When do the back billing rules apply to me? 

  • When do the back billing rules not apply to me? 

  • I think my supplier sent me an erroneous back bill – what should I do? 

  • What happens if I can’t afford to pay for my overdue energy bill? 

  • Will back billing continue to be an issue in the future? 

What is back billing? 

Put simply, back bills are catch-up bills that your energy supplier sends to you when it didn’t charge you correctly for the energy you’ve been using. Although it seems surprising that energy suppliers would make errors in such a key area, it still occurs surprisingly often, judging by the number of complaints and fines handed out – a staggering £53 million has been paid in fines by the big six energy suppliers in recent years for so-called ‘bad billing’ practices.

Back in 2016-2017, Citizens Advice published figures from a random sample of back-bills to reveal the median back-bill for the average home energy customer came to a staggering £1,160 – not far short of an average household’s annual bill – and in some cases it can be significantly more, up to £10,000 in some rare cases.

It’s a significant amount of money to find at short notice, and if you’ve been incorrectly undercharged for your energy bill, you could end up needing to repay a substantial amount. This can have a serious effect on your household’s finances, so it’s important to know exactly what to do if you encounter any issues with back billing from your energy supplier. 

Why did I get charged for an old electricity bill? 

There are several different reasons why your energy supplier may have made an error when calculating your electricity or gas bill. Here are some of the most common reasons for back billing: 

ReasonExplanation
Estimated meter readings In most cases, households rely on estimated meter readings, rather than providing meter readings to their energy suppliers throughout the course of the year. In some cases, this means that customers will either underpay or overpay. Due to internal oversight on the part of the energy supplier, these incorrect payments may go unnoticed for a significant period, leading to back billing.
Incorrect meter information Sometimes, a household will be paying for energy from an incorrect meter number. This means that your household may unknowingly be paying for energy usage from another property. If this other property has a lower energy usage than your own property, you may have been underpaying, leading to back billing.
One-off mistakes Most of the time, back billing is simply the result of a one-off mistake from the supplier or the customer. For instance, a customer may ask for their direct debit to be reviewed in the case of an energy credit, and the supplier may accidentally cancel the direct debit. This cancellation may go unnoticed for a significant period, and when it is discovered, the customer will have missed several payments, leading to back billing.

Are there any back billing rules? 

Fortunately, there are a set of principles – known as the Ofgem back billing rules or the back billing principles – that can help you work out what to do if you’ve received a back bill from your energy supplier. Essentially, these back billing rules state that energy suppliers cannot attempt to rectify incorrect energy charges from longer than 12 months ago, assuming that the supplier was the party at fault, not the customer. 

When do the back billing rules apply to me? 

If your supplier has sent you an incorrect energy bill from over 12 months ago, you may not need to pay it if the following conditions are met: 

  • Your supplier sent you an incorrect electricity bill by mixing up the meter readings and then failing to act on the available information to correct its error.

  • Your supplier failed to bill you, even when you requested bills from it.

  • Your supplier billed you using estimated meter readings rather than meter readings provided by you or a meter reader.

  • Your supplier did not reassess a payment arrangement (for example, a request to change your direct debit) within 15 months, or your supplier did not reassess based on reasonable estimates.

  • Your supplier did nothing about a query you raised about your account or meter, thereby allowing a large energy debt to build-up.

If the above applies to your electricity bill, you may be in line to receive a back bill write-off. The next step should be to contact your energy supplier for more information

When do the back billing rules not apply to me? 

There are some situations in which you may be judged to be at fault for back billing, which means that you’ll still need to pay for the underpaid energy bill. Here are some of the conditions that could mean you still need to pay: 

  • You wilfully avoided paying for your energy bill.

  • You used gas or electricity but made no attempt to arrange payment with your supplier (for instance, you moved into a new house and did not let your supplier know that you were the new resident).

  • You have not allowed your supplier to obtain meter readings or resolve queries (for example, you may have prevented it from entering the property or failed to respond to requests for meter details or meter readings).

If the above applies to your energy bill, you probably won’t be able to get a back bill write-off. This means that you will need to pay for the back billing that you’ve received. 

I think my supplier sent me an incorrect back bill – what should I do? 

If you believe you have been sent an erroneous gas or electricity bill, the first thing to do is contact your energy supplier. It will have a specific set of guidelines for handling complaints that you should follow. If the complaint hasn’t been resolved, there are further steps you can take, or you can contact Citizens Advice for more information. If the situation still has not been solved, you can contact the Energy Ombudsman.

What happens if I can’t afford to pay for my overdue energy bill? 

If you’re required to pay for back billing, it’s possible that you won’t have enough money to pay the outstanding amount all at once. This is sometimes an issue when households have already budgeted for their energy bills before getting hit with an electricity bill for thousands of pounds from 12 months ago. In this situation, you can ask your energy supplier to set up a payment plan that will allow you to repay the electricity bill over the same length of time that the debt built up. For example, if the back billing stretches back nine months, you should be able to set up a payment plan that spreads your repayments across nine months. 

Will back billing continue to be an issue in the future? 

The introduction of new processes like smart meters should reduce the amount of back billing that customers will have to deal with in the future. However, customers with smart meters still encounter issues with back billing, and according to Citizens Advice, around 3% of smart meter customers haven’t received an accurate bill for over six months. 

All in all, back billing can have a huge effect on your household’s finances, so it’s important that you understand what your rights are when it comes to these so-called “shock bills”. If you think you’ve been erroneously charged for your energy bills, you should get in touch with your energy supplier as soon as possible, as it’s important to resolve these issues as quickly as you can. 

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Published on Wed 23 Oct 2019 03.30 GMT