What to do if you get an energy back-bill
Been billed for energy used over a year ago? You DON'T need to pay it
Energy firms are banned from hitting you with an unexpected bill for any energy you used more than 12 months ago, that you haven't been correctly billed for before. But there are over 3,000 complaints to the ombudsman of just this happening – here's what you need to know...
What is energy back-billing?
If your gas or electricity supplier believes you haven't been correctly billed for the energy you've used, it might send you a back-bill (sometimes known as a 'catch-up' bill). This type of bill covers a period where you either weren't charged at all, or you were charged the wrong amount for your energy use.
How far back can energy companies back-bill me?
Under Ofgem's rules, you can't be charged for energy you used over 12 months ago, if any of the following apply:
You didn't receive an accurate bill for that energy, despite asking for one.
You weren't informed about the charges in a statement of account.
Your Direct Debit was set too low to cover the full amount, and this wasn't corrected.
Under the energy regulator Ofgem's rules, a supplier can only issue a back-bill where the customer has 'unreasonably obstructed' it before – yet, as Martin Lewis explained in his evidence to the Commons Energy Committee of MPs, that's poorly defined, so right now many complaints fall into a grey area. He urged Ofgem to provide more specific guidance on exactly what's considered an obstruction.
Ofgem's back-billing rules apply to all payment methods, regardless of the payment type, meter mode or meter arrangements.
But for now, the back-billing rules don't apply if you have "acted unreasonably". This could include stopping your supplier from billing you accurately (for example by blocking access to your meter) or ignoring requests for payment from your supplier.
But remember, if you do get a back-bill that's less than 12 months old, you will have to pay it, unless you believe your supplier has made a mistake. In which, you can raise a dispute with your supplier, and escalate it to the Energy Ombudsman if necessary.
What to do if you've received a back-bill
DON'T just ignore a back-bill if you get one – here's what to try instead:
Step 1: Challenge your energy firm to explain exactly why it's back-billing you
Energy firms are required to bill you accurately and promptly. If yours hasn't – and you haven't unreasonably obstructed it – then it can't suddenly issue you a bill for energy used over 12 months ago that it hasn't correctly billed you for before.
Step 2: If you're not happy with its response, raise a formal complaint
You can do this directly with the firm or using the free Resolver tool, which will keep track of your progress and evidence.
Step 3: As a last resort, escalate your complaint
If you've already tried contacting the firm and it's been more than eight weeks since you lodged your formal complaint (or you've received a deadlock letter), you can then take it to the Energy Ombudsman, a free and independent body that handles disputes between consumers and energy firms.
To give you some encouragement, Nathalie emailed us her back-billing success:
Thank you Martin, I just got a £152 refund for energy on a former property that Octopus didn't initially bill me for. I remained an Octopus customer at my new house, and the old account was linked to my new one, but they didn't bill me anything for my previous property.
It was over a year later, when I got bailiff's letter chasing a debt I didn't know I had. I called Octopus at the time (November 2024) and paid immediately because bailiffs' letters are scary.
But I have since heard about Ofgem's back-billing rules, so I called Octopus, they looked into it and have refunded the entire amount immediately. Thanks so much!! I really needed that £152.
Give regular meter readings and check your bills to avoid back-bills
While it's not full proof, the best way to avoid getting a back-bill is to make sure you get regular, accurate bills from your supplier:
Consider getting a smart meter. This will automatically send regular meter readings directly to your supplier, so you should be billed accurately for what you use. If you already have one, make sure it's operating in 'smart mode' and sending readings to your provider.
Give regular meter readings. If you don't have a smart meter, make sure you submit regular meter readings to get a more accurate bill.
Check your bills. Make sure you're receiving regular bills and that the amount you're being billed for accurately reflects the energy you've used. If you think your bill is not right, contact your supplier as soon as possible. If you're not sure what to look for, get help to understand your electricity and gas bills. You should also let your supplier know if you haven't received a bill for energy you've used.
What to do if you're struggling to pay your energy bills
There are several key areas you can focus on:
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Have you got all the help you qualify for? Your energy supplier has to help if you're struggling to pay your energy bills. You can see a full rundown of what's available in our What to do if you're struggling with energy bills guide. You can also use our free 10-minute benefit checker to see if you're missing out on any benefits or grants.
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Check you're paying the right amount. You can use our Energy Price Cap Calculator to see how much you should be paying if you're not on a fixed energy deal, and find out how to get back energy bill credit from your supplier.
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Switch to a cheaper energy tariff. Most households can save £100s on energy bills by switching to a cheaper supplier or tariff. Join our Cheap Energy Club comparison site to get a bespoke comparison of predicted costs over the next year, compared to switching. Full info on how to switch energy supplier in our guide, plus our Should you fix your energy? guide has info on the alternatives to fixing.
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Try to cut your energy usage. There are lots of way to reduce what you use. Check our 70+ energy savers checklist for pain-free changes, such as turning down your thermostat or tweaking your boiler's flow temperature. Also, see our Heat the human and Energy mythbusters guides for more tips.
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Check if you can get a free boiler or insulation. There are wads of freebies or grants from energy providers, from help with new boiler costs to free loft and cavity wall insulation. It's all part of their efficiency obligations to people in certain groups. It's mainly for those receiving certain benefits, such as Universal Credit, Tax Credits, Pension Credit or income-based benefits. See Great British Insulation Scheme guide for more info.
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