The average dual fuel bill has increased by 24% between 2009 and 2013.
Latest figures from Ofgem reveal gas and electricity bills in 2013 stood at £1,225 on average – from £1,043 in 2009.
The cheapest available fixed tariff in May this year was around £900 a year compared to the average variable tariff at £1,165 a year.
According to the regulator, the UK ranks “above average” on electricity prices and “around average” on gas prices compared with the rest of Europe.
Currently there are 29 “active suppliers” in the domestic energy market, with 24 providing both gas and electricity, three solely supplying gas and two providing only electricity.
The market share of independent suppliers was 9.7% in March this year compared to 2% in January 2013.
Between January and April this year, 900,000 gas customers and 1.1 million electricity customers have switched suppliers.
Around 37% of them moved to independent suppliers.