UK consumers could save £1bn a year on energy bills by switching supplier and installing better efficiency measures, the government has estimated.
Poverty warning: Rising fuel bills will hurt the vulnerable this winter
On Monday, it launched an "Energy Smart" campaign to encourage people to save money on their bills.
Rising prices will add £5.2bn to energy bills this year, causing problems for people on low incomes.
Half of all households have never changed supplier, although first time switchers could save up to £100 a year.
Consumer groups are concerned that rising fuel bills over the last year will cause problems for vulnerable people this winter.
Rising wholesale oil prices have pushed up residential bills. The average gas bill has increased by 18% this year, and the cost of electricity has risen by 14% on average.
The new awareness campaign is being jointly run by Energywatch, the energy consumer watchdog and Ofgem, the energy industry regulator.
"Consumers have been hit hard this year by rocketing fuel bills but being energy smart can save money," said Allan Asher, chief executive of Energywatch.
"The hike in energy bills is forcing vulnerable consumers into fuel debt and poverty this winter.
"Dumping expensive suppliers, being more energy efficient and changing payment method are all ways of savings lots of money."
The scheme was launched by Trade and Industry Secretary Patricia Hewitt and Energy Minister Mike O'Brien.
Ms Hewitt said: "We know that for many families fuel bills are a significant part of their weekly outgoings, and we need to do more to help the most vulnerable consumers benefit from big savings that are out there.
"Our message today is simple - why pay more for your gas and electricity than you need to?"
The National Audit Office reported last year that consumers who had never switched supplier were likely to be paying 22% more for their fuel than people who had.
As well as making typical savings of up to £100 a year for switching supplier, customers save about £20 a year if they switch their payment method - from cheque or cash to direct debit.
Installing cavity wall insulation will save a further £35 a year.
Pre-payment meter customers, who generally pay more for their energy, can make further savings, the campaign organisers said.
Since February, new rules mean gas and electricity customers on a prepayment meter who owe less than £100 cannot be prevented from switching suppliers.