Which ombudsman does 100Green belong to?
The Energy Ombudsman. Complain to 100Green first; if it is not sorted within 8 weeks — or 100Green sends a deadlock letter — the Energy Ombudsman can look at it for free and order 100Green to put things right.
Short answer
The Energy Ombudsman — the free, impartial service that resolves disputes with energy suppliers in Great Britain. You go to it after complaining to 100Green and waiting 8 weeks, or sooner if 100Green sends a deadlock letter.
How to take a complaint about 100Green to the Energy Ombudsman
- Complain to 100Green first, in writing if you can, and keep the reference.
- Allow 8 weeks for it to be put right — or less if the supplier sends a deadlock letter saying it cannot do more.
- Register the dispute with the Energy Ombudsman online, by phone, email or post. It is free.
- You must escalate within 12 months of receiving the deadlock letter.
- Both sides send evidence within 14 days; the Ombudsman reviews it and makes a decision.
- If you accept the decision, the supplier has 28 days to carry out the remedy.
The Ombudsman can tell a supplier to take practical action — credit your account, cancel an account, change your tariff — apologise, or pay a financial award. It cannot punish or fine a supplier. Need the letter? Our free complaint letter generator cites the licence conditions, and the Ombudsman vs Ofgem guide explains who handles what.
Questions
Which ombudsman does 100Green belong to?
The Energy Ombudsman — the free, impartial service that resolves disputes with energy suppliers in Great Britain. You go to it after complaining to 100Green and waiting 8 weeks, or sooner if 100Green sends a deadlock letter.
How long does 100Green have to resolve my complaint?
8 weeks. After that — or straight away if you receive a deadlock letter — you can take the dispute to the Energy Ombudsman. You must do so within 12 months of the deadlock letter.
What can the Energy Ombudsman make a supplier do?
Take practical action (for example credit your account, cancel an account or change your tariff), apologise, or pay a financial award — or a combination. It cannot fine or punish a supplier; that is Ofgem’s job.
Is 100Green still trading?
Yes as of 30 September 2026: 100Green is on gov.uk’s list of suppliers taking part in the Warm Home Discount for winter 2026 to 2027. Formerly Green Energy UK (GEUK).
Other suppliers
Boost · British Gas · E (Gas and Electricity) · Ecotricity · EDF · EnergyCoop · E.ON Next · Fuse Energy · Good Energy · Home Energy · London Power · Octopus Energy · Outfox the Market · OVO · Sainsbury's Energy · Scottish Gas · ScottishPower · So Energy · Square 1 Energy · TruEnergy · Tulo Energy · Utilita · Utility Warehouse
Process from energyombudsman.org and its FAQs; trading status from the gov.uk Warm Home Discount supplier list, read 30 September 2026. General information, not legal advice. All suppliers A–Z.
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