Consumer groups have urged households not to wait for Ofgem to make energy bills simpler and fairer, with the difference between the cheapest and most expensive tariffs currently standing at around £300.
Gillian Guy, chief executive of Citizens Advice, welcomed Ofgem's "long overdue" announcement, but said consumers should act swiftly to cut their bills as they are losing money "every day".
She warned: "Thousands of households could lose out this winter if they don't check now that they're on the best deal."
Citizens Advice is hosting Big Energy Saving Week from next Monday, which will give people advice on how to cut down their bills.
Ann Robinson, director of consumer policy at comparison website uSwitch, said that households facing a winter of energy price hikes may not be able to afford to wait for the measures to take effect.
She said: "There is currently £300 difference between the cheapest and most expensive tariffs on the market."
Audrey Gallacher, director of energy at Consumer Focus, said Ofgem's announcement was a "positive first step" and pointed out that energy switching rates have been falling, from around 20% of customers switching in 2008 to 15% in 2012.
She said: "Vulnerable consumers are hit hardest by price rises, are less likely to shop around and are more likely to be on the most expensive rates. Extra steps should be made to alert vulnerable households if they could be on a better deal. Thought will be needed on how best to reach this group and encourage them to take up a cheaper rate."
Many households have already been squeezed by increased mortgage costs after a string of lenders increased their standard variable rates (SVRs) in recent months, affecting more than a million homeowners.
Food prices have also been predicted to rise following poor harvests due to the wet British weather as well as the worst drought in 50 years in the US.