Only 13 per cent of households have signed up to online energy plans, leaving 87 per cent paying around £300 more than they need to for their gas and electricity.
According to comparison website uSwitch.com, the cheapest energy tariffs are to be found online, and the 10 million households which are still on standard energy plans are paying over the odds to the tune of a total £2.2billion a year.
Even people who do switch suppliers might not be getting the best deal, the website suggests, because recent research from Ofgem shows that despite its efforts to encourage consumers to shop around, only 30 per cent did so using an online service to compare gas and electricity prices.
A third of households switched due to a supplier knocking on their door, while a further 61 per cent of switchers found out about what deals were available through their existing suppliers, which is no guarantee that they were being offered the cheapest deal on the market.
Ofgem is taking action to encourage households to find the cheapest energy plan for them, including introducing annual statements, which will see each home receive a yearly prompt to check prices.
Suppliers are also under pressure to display their current cheapest tariffs on their customers' bills; uSwitch hopes that such rules as this will see a sharp increase in the number of consumers opting to compare energy prices to find the cheapest deal.
Ann Robinson, director of consumer policy at uSwitch.com, commented: "No matter how these figures are dressed, the fact that just one in ten British households are paying the cheapest energy prices on the market is a huge disappointment and means that Ofgem really does have its work cut out."
The energy market is competitive, she argues, but Ofgem still needs to work on increasing the number of people taking advantage of the potential savings to be made, which could take their energy bills back down to 2008 levels.
Ms Robinson added: "I would urge householders to move to dual fuel, pay by direct debit and sign up to an online plan so that they can start to enjoy competitive prices straight away."
The need to compare prices has been heightened during the last week, which has seen the most competitive deals withdrawn and replaced by more expensive tariffs.
© Fair Investment Company Ltd
Click on the link below to compare energy prices and switch: