Got the wrong bill from E.ON Next? Here is how to fix it.
This guide explains who E.ON Next is, why the Npower takeover in 2020 is still causing billing problems years later, the law that protects you (especially the 12-month back-billing rule), and how to send E.ON Next a proper complaint letter by Royal Mail.
About E.ON Next Energy Limited
E.ON Next is a UK energy supplier that started in July 2020. It is the UK retail brand of E.ON SE, a huge German energy company based in Essen, Germany. E.ON SE is listed on the Frankfurt Stock Exchange and is one of the largest investor-owned energy companies in the world. The "E.ON" name was created in 2000 when two big German energy companies (VEBA and VIAG) merged. E.ON UK has been operating in Britain since 2002, after E.ON bought Powergen (which started as a state-owned UK electricity supplier in 1989 when the electricity market was privatised).
The legal entity behind E.ON Next is "E.ON Next Energy Limited" (Companies House number 03782443). Here is something a lot of customers do not realise: this is literally the same legal company that used to be called "Npower Direct Limited". The company was incorporated in 1999 under another name, became Npower Direct Limited in September 2000, and was renamed E.ON Next Energy Limited on 3 June 2020. So when E.ON took over Npower in November 2019 and started migrating customers in July 2020, they used the existing Npower legal entity. The head office is in Coventry.
E.ON Next was the first of the old "Big Six" UK energy suppliers to switch ALL its residential electricity customers to 100% renewable electricity, back in 2019. The company serves around 5 million UK customers today. E.ON Next also runs on a technology platform called Kraken — which is the same platform built by Octopus Energy and now used by lots of energy companies around the world. Kraken was spun off as an independent technology company in December 2025 with a valuation of $8.65 billion. So if E.ON Next's website and app feel a bit like Octopus's, that is because they share the same underlying technology.
Registered office
E.ON Next Energy LimitedWestwood Way, Westwood Business Park
Coventry, West Midlands
CV4 8LG
United Kingdom
Companies House number: 03782443 · Incorporated: 4 June 1999 (renamed to E.ON Next Energy Limited on 3 June 2020; previously Npower Direct Limited from September 2000) · Parent: E.ON UK plc, ultimately E.ON SE (Essen, Germany) · Regulator: Ofgem (Office of Gas and Electricity Markets) · Ombudsman scheme: Energy Ombudsman (run by Ombudsman Services)
Group structure
E.ON SE (German parent)
This is the German parent company at the top of the group. It is registered in Essen, Germany. Listed on the Frankfurt Stock Exchange and a member of the DAX (the German equivalent of the FTSE 100). E.ON SE owns energy companies across Europe. It came into being in 2000 from the merger of two German firms called VEBA and VIAG. In 2019 it bought a big share of Innogy SE (the company that owned Npower in the UK), which is how the UK Npower business came under E.ON ownership.
Frankfurt Stock Exchange listed. DAX member.E.ON UK plc
This is the UK holding company between E.ON SE in Germany and E.ON Next. It used to be called Powergen plc back in the 1990s. Today it owns the UK energy businesses including E.ON Next Energy Limited (residential supply), Npower Commercial Gas Limited (business customers under the "npower Business Solutions" brand), and various other UK energy companies. CEO is Chris Norbury.
Formerly Powergen (1989–2002).E.ON Next Energy Limited
This is the company that actually holds your gas and electricity supply contract. Companies House number 03782443, based at Westwood Business Park in Coventry. This is the legal entity you serve in any UK court case about a wrong bill. Its previous names (Hackremco No.1496, Nitrogen Two, Npower Direct) show that this is literally the same legal vehicle that used to run Npower's residential supply business before the 2020 rebrand.
Companies House 03782443. Ofgem-licensed supplier.Old Npower customers and Powershop customers (migrations)
E.ON Next has grown by taking over customers from other brands. Around 4 million residential Npower customers were migrated to E.ON Next starting in July 2020. About 2 million more came over from Powershop UK after E.ON bought that business too. Some old E.ON UK customers were also migrated. All this migration is the biggest single source of incorrect bills from E.ON Next, as explained next.
Common reasons your E.ON Next Energy Limited bill might be wrong
- 1Migration mix-up from old Npower or Powershop. Migration between billing systems is risky. Old meter readings, direct debit dates, account credit balances, and tariff details sometimes do not transfer correctly. If you were an Npower or Powershop customer before 2020, the closing balance from your old supplier MUST match the opening balance on your E.ON Next account. If they do not, something has gone wrong.
- 2The smart meter has not been sending readings. This is the biggest single cause of wrong bills across all UK energy suppliers. E.ON Next then bases the bill on an estimate, which is often wrong (especially in winter). You can check by taking your own meter reading and sending it to E.ON Next.
- 3You were back-billed for more than 12 months. Standard Licence Condition 21BA says E.ON Next CANNOT charge you for energy used more than 12 months ago if the missed billing was THEIR fault. This is explained in detail below.
- 4The wrong tariff was applied during migration. Some customers were moved onto E.ON Next's default tariff instead of being placed on a fixed-rate equivalent of their old Npower tariff. The price difference can be hundreds of pounds a year.
- 5A prepayment meter compensation claim. E.ON Next was named in Ofgem's industry-wide prepayment meter investigation alongside other suppliers. If a prepayment meter was forcibly installed in your home between 2022 and 2023, you may be entitled to compensation.
- 6Direct debit went up without proper justification. E.ON Next has to give you fair notice and a clear breakdown if they want to raise your monthly payments. Big unexplained jumps can be challenged.
The energy billing rules that protect you
| Rule | What it means | Source |
|---|---|---|
| 12-month back-billing rule | If your energy supplier did not bill you accurately because of their own mistake, they cannot now charge you for energy used more than 12 months ago. | Standard Licence Condition 21BA (domestic), SLC 7A (microbusiness). In force since 1 May 2018. |
| Standards of Conduct | Suppliers must treat you fairly, give you clear information, and make sure billing is accurate. | SLC 0 and 0A. |
| Priority Services Register | If you are vulnerable, you get extra protections including more regular meter reads. | SLC 26. |
| Default Tariff Cap | Limits the amount per unit and standing charge if you are on a default or "standard variable" tariff. | Reset every quarter by Ofgem. |
E.ON Next is signed up to all of these rules because they hold a UK gas and electricity supply licence from Ofgem. The back-billing rule (Standard Licence Condition 21BA) is particularly important for E.ON Next customers because the 2020 migration from Npower has caused many billing gaps that only get spotted years later.
The Npower migration and how it affects your bill
E.ON took over Npower in November 2019 as part of a complex €43 billion asset swap deal between E.ON, Innogy and RWE. The European Union approved the deal in September 2019. The final pieces were executed in July 2020. As part of all this, E.ON renamed the existing Npower Direct Limited company to "E.ON Next Energy Limited" on 3 June 2020 and started moving Npower customers across to the new E.ON Next brand from July 2020.
Around 4 million Npower residential customers were transferred between 2020 and 2022. Migrations of this size always cause billing issues. Old meter reads, direct debit amounts, account credit balances, tariff details and customer service history sometimes do not transfer cleanly. Years later, some customers are still finding mistakes that go back to the original Npower account.
What this means for you: if you were an Npower customer before 2020 and your E.ON Next bills do not add up, the migration is a very likely cause. The closing balance from your last Npower bill should match the opening balance on your first E.ON Next bill exactly. If they do not match, demand a reconciliation. You can also use Standard Licence Condition 21BA to argue that any back-billed period more than 12 months before the first accurate bill should be written off. The fact that the legal company (E.ON Next Energy Limited, Companies House 03782443) is literally the same one that used to be Npower Direct Limited means E.ON Next CANNOT say "that was Npower's problem". It is the same company. They inherited everything, including the obligations.
Your rights
Standard Licence Condition 21BA (the back-billing rule)
This is the big one. E.ON Next cannot bill you for gas or electricity used more than 12 months ago if E.ON Next (or Npower, since it is the same legal entity) was at fault for not billing accurately. The rule lives in the Standard Conditions of Electricity Supply Licence and the Standard Conditions of Gas Supply Licence, both made under the Electricity Act 1989 and the Gas Act 1986. It has been in force since 1 May 2018.
Standard Licence Conditions 0 and 0A (Standards of Conduct)
These set out broad rules about how E.ON Next has to treat you. They have to be fair, give you clear information, use plain language, and make sure billing is accurate. Migration errors that are not properly fixed when raised can be a breach of these standards.
Standard Licence Condition 21B and 21BA (your bill must be accurate)
E.ON Next has to take all reasonable steps to base your bills on actual meter readings. If they only have estimated reads, they have to clearly mark the bill "estimated" and try to get an accurate read. If they have a smart meter that is sending readings, they must use the actual readings, not estimates.
Standard Licence Condition 31I (direct debit changes)
If E.ON Next wants to put your monthly direct debit UP, they have to give you fair notice and a clear breakdown of why. If your usage has not changed and your payments are already covering your costs, they cannot just put it up. Big unexplained jumps can be challenged.
Consumer Rights Act 2015, sections 49 and 51
This is the general consumer law that applies to all services in the UK, including energy. Section 49 says services must be performed with reasonable care and skill (which includes accurate billing and good migration handling). Section 51 says the price must be reasonable if it is not agreed in advance.
How long do you have to challenge a bill?
The Limitation Act 1980 gives you 6 years to bring a court claim about a contract dispute in England, Wales and Northern Ireland (5 years in Scotland). For Npower migration issues that go back to 2020 or earlier, that 6-year clock is now ticking and may be running out for some accounts. Act sooner rather than later.
Common E.ON Next Energy Limited situations
Your old Npower account did not migrate correctly
This is the special E.ON Next situation. The closing balance on your last Npower bill should match the opening balance on your first E.ON Next bill exactly. If you had Npower credit that disappeared, an Npower debt that grew unexpectedly, or meter readings that do not line up around the transfer date, the migration is at fault. Quote your Npower account number, the migration date (between July 2020 and 2022 for most customers), and demand a full reconciliation. The fact that E.ON Next Energy Limited (Companies House 03782443) IS the old Npower Direct Limited (just renamed) means they cannot pass the blame.
You got a huge catch-up bill after months of estimates
This is the classic SLC 21BA case. If E.ON Next has been sending you estimated bills and then suddenly sends you a corrected bill for more than 12 months of usage, write to them quoting SLC 21BA. Ask them to cap the bill at the 12 months immediately before the corrected bill date. You only have to pay for that 12-month window. The earlier part has to be written off.
Your smart meter has not been sending readings
Smart meters sometimes lose their signal. When that happens, E.ON Next's system uses estimates. The first thing to do is take a manual reading and send it to E.ON Next. If they failed to spot the problem for many months and now want to back-bill you, the back-billing rule applies. E.ON Next has a duty to notice and fix the problem.
You think a prepayment meter was wrongly installed
E.ON Next was named in the industry-wide Ofgem prepayment meter investigation. If a prepayment meter was forcibly installed in your home between 2022 and 2023, you may be entitled to compensation. The settlement is smaller than British Gas's separate £112 million programme but the principle is the same. Reference the Ofgem industry-wide PPM Market Compliance Review of 2024 in your letter.
You are on the wrong tariff
Check your tariff name on the latest bill. If you signed up for a specific E.ON Next fixed tariff but are being billed on the default variable tariff instead, you are being overcharged. This happens especially during migration from Npower. Send E.ON Next a letter quoting the tariff you signed up for and the dates. They have to put you back on the right one AND refund the difference.
Your direct debit went up sharply
E.ON Next has to follow SLC 31I when changing your direct debit. They must give fair notice and a clear breakdown of why. If your usage has not changed but your monthly direct debit went up a lot, demand a written explanation. Your credit balance, recent usage and current tariff should all line up with the direct debit amount.
E.ON Next is ignoring your complaint
After 8 weeks of unresolved complaint or after getting a final "deadlock" letter from E.ON Next, you can take the case to the Energy Ombudsman free of charge. The Energy Ombudsman makes binding decisions. A formal letter sent first by Royal Mail makes the Ombudsman case much stronger.
Send your E.ON Next Energy Limited complaint by Royal Mail
PostRight writes your formal complaint letter for you. Answer a few simple questions. Check the letter. Pay. We print it and post it by Royal Mail the next working day. A real letter creates a clear paper trail that matters for back-billing claims and Energy Ombudsman escalation.
- ✓Cites Standard Licence Condition 21BA where the back-billing rule applies
- ✓References the old Npower account where the issue stems from migration
- ✓Quotes the Consumer Rights Act 2015 where service was not properly carried out
- ✓States exactly what you want E.ON Next to do (refund, recalculation, direct debit adjustment, balance correction)
- ✓Gives E.ON Next a clear 14-day deadline to reply
- ✓Printed on quality paper and posted by Royal Mail. From £2.79.
Frequently asked questions
I used to be an Npower customer. Is my account safe?
It is the same legal entity. E.ON Next Energy Limited (Companies House 03782443) was Npower Direct Limited until 3 June 2020. So you are still legally a customer of the same company, just under a different brand. Your old Npower account history should still be available. If E.ON Next claims they cannot find your old records, that is THEIR problem, not yours, because the company never changed — just the name on the door.
What is the back-billing rule and does it apply to E.ON Next?
Yes, it applies to every UK gas and electricity supplier including E.ON Next. Standard Licence Condition 21BA says that if E.ON Next failed to bill you accurately because of their own mistake, they cannot now charge you for energy used more than 12 months ago. So if you suddenly receive a catch-up bill for 18 months or two years of energy, write to E.ON Next quoting SLC 21BA and demand the bill be capped at 12 months.
My migration from Npower was years ago. Can I still complain?
Probably yes. For the back-billing rule, the clock counts from the date of the first accurate bill, not from the date of any underlying problem. So if migration mistakes are only being noticed now in 2026, you can still use SLC 21BA. For going to court, the 6-year limit applies. So you might still have time to challenge bills going back to mid-2020 if the migration date was July 2020 or later.
My smart meter stopped sending readings. Whose fault is that?
Smart meter signal problems are usually the supplier's responsibility. E.ON Next has a duty to monitor data and fix problems they spot. If your meter stopped sending readings and E.ON Next failed to notice for many months, that is THEIR fault, not yours. You can use the 12-month back-billing rule. You should also try to send manual readings whenever you spot a problem.
How do I escalate to the Energy Ombudsman?
First make a formal complaint to E.ON Next in writing. They have 8 weeks to resolve it. If they refuse or you have a final "deadlock" letter, you can take the case to the Energy Ombudsman at energyombudsman.org or by calling 0330 440 1624. The service is free for customers and binding on E.ON Next. The Ombudsman can order E.ON Next to pay you compensation, write off charges, or apologise.
Was E.ON Next involved in the prepayment meter scandal?
Yes, but in a smaller way than British Gas. E.ON was named in Ofgem's industry-wide Market Compliance Review of prepayment meter installations between 2022 and 2023. Together with seven other suppliers, E.ON paid into a combined £73.6 million compensation pot. The British Gas settlement of £112 million was separate and bigger because of the specific failings identified at that company. If your prepayment meter was forced on you by E.ON Next staff or contractors, your claim may fall under the industry-wide review.
Why does E.ON Next look like Octopus?
Because E.ON Next runs on the Kraken technology platform built by Octopus Energy. Kraken handles the account, billing, customer service and tariff systems for both Octopus and E.ON Next, plus other big energy suppliers like EDF. Kraken was spun off as an independent company in December 2025 with a valuation of $8.65 billion. So the underlying tech is the same, but E.ON Next and Octopus are still separate companies with separate prices, tariffs, and customer service teams.
Can I get E.ON Next to refund a credit balance to my bank?
Yes. If your E.ON Next account is in credit (you have paid more than you used), you can ask for the credit to be refunded to your bank account. Their standard practice is to refund credit balances at the annual review, but you can ask any time. The money is yours.
Free help and what to do next
Energy Ombudsman
Free, binding dispute resolution for energy customers. After 8 weeks of unresolved complaint or a final response from E.ON Next, take your case here. Decisions are binding on E.ON Next. Free for you to use. Helpline: 0330 440 1624.
Visit website →Ofgem (the regulator)
The UK energy regulator. Does not handle individual complaints but enforces the licence conditions. Ofgem ran the industry-wide prepayment meter Market Compliance Review that named E.ON. Worth reporting persistent bad behaviour to add to the enforcement record.
Visit website →Citizens Advice Consumer Helpline
Free advice on energy bills, switching, fuel poverty support and consumer rights. Operated alongside Ofgem. Helpline: 0808 223 1133.
Visit website →Money Claim Online (MCOL)
The online court service for England and Wales. Use this if E.ON Next refuses to follow an Ombudsman decision, or to sue E.ON Next directly. You have 6 years from the date of the disputed bill to sue (5 in Scotland). For old Npower migration issues from July 2020, this 6-year window is starting to count down.
Visit website →Ready to challenge your E.ON Next Energy Limited bill?
PostRight prints and posts your formal complaint letter by Royal Mail. From £2.79. Add Tracked 24 for £9.99 if you want proof of delivery. A posted letter cited under SLC 21BA is the strongest opening move for any back-billing case.
Send an E.ON Next Energy Limited letter from £2.79From £2.79 · Printed and posted by Royal Mail · Dispatched within one business day