It found that E.ON spent more money per customer account than any other energy firm during 2007/08 on helping its consumers.
Graham Bartlett, managing director of E.ON's Retail business, said it was "heartening" to hear the results, adding the energy firm has extended its social programme through the launch of WarmAssist, which offers its customers over the age of 60 a 15 per cent reduction in electricity and gas prices.
He stated: "We've always taken our commitment to helping our most vulnerable customers extremely seriously and it's reassuring to be recognised by Ofgem as spending the most per customer account."
E.ON recently announced it was reducing its annual bills for electricity customers who are not connected to mains gas by £14 per year.
The move affects its customers in the East Midlands, east of England and the north-west.
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