A consumer watchdog has warned that rising fuel bills will lead many to worry about the cost of heating their home this winter.
Consumer Focus claims the above-inflation rises, of up to 20%, will push heating bills towards the Â£1,250 a year mark.
E.ON's hikes follow similar rises from three of the other "Big Six" suppliers, who provide energy for 99% of the UK, with Scottish Power, British Gas and Scottish and Southern Electricity all increasing fuel prices.
Chief executive Mike O'Connor said: "Yet another price rise will leave the average energy bill weighing in at Â£1,250 a year.Â Many consumers worry how they will afford to keep their homes warm this winter given other price rises and flat or falling incomes.Â Four of the Big Six have now raised their prices by similar amounts.
"The regulator must be prepared to act if it can't say for certain whether prices are fair. If consumers are to stomach such price rises, they need to know they are fair."
Latest gas and electricity news brought to you by UK Power - the energy price comparison site.
Click here to run an energy price comparison, and see if you could be paying less for your gas and electricity.