The agreed redress package displays the harm caused by E.ON’s poor sales practices carried out for three years, Ofgem said.
An investigation by the Ofgem has revealed that E.ON had failed to have in place sufficient safeguards to ensure the appropriate selling of energy tariffs.
E.ON has acknowledged to its customers and confirmed it is working to ensure the failings of the past cannot be repeated again.
As part of the redress package E.ON has agreed to pay around £35 to 333,000 of its customers who are normally recipients of the Warm Home Discount.
In addition, the company will make automatic payments to some vulnerable customers who may have been affected by the poor sales practices.
E.ON has established a dedicated hotline and will write to around 465,000 identified customers through its redress work, outlining them of how to get in touch to find out whether they were mis-sold to.
E.ON UK chief executive Tony Cocker said, "We are really sorry and want to make it absolutely clear that we’re putting this right."
Ofgem senior partner in charge of enforcement Sarah Harrison said, "Since 2010 Ofgem has imposed nearly £100m in fines and redress on energy companies for various rule breaches, including £39m for mis-selling, and introduced radical new reforms to make the market simpler, clearer and fairer for consumers.
"E.ON has today taken a good step by accepting responsibility for its actions and putting proper redress in place," Harrison said.
