More than 400,000 people ditched the largest six energy suppliers in June and July in a bid to save money as the economy entered a recession and energy usage went up due to home working.
The figures, from trade association Energy UK and auto-switching company Flipper, revealed a 25pc increase on the same period last year.
In total, nearly one million households switched suppliers to cut costs. The most common switch was from larger to small and mid-sized companies.
“People are now seeing the impact of the increase in home energy usage since lockdown in their bills and are taking action. With pressure on household budgets expected to increase in the coming months as the furlough scheme ends, we expect this trend to continue,” said Mark Gutteridge, of Flipper.
Until 2013, the Big Six energy companies, made up of SSE, EDF Energy, British Gas, Npower, E.on and Scottish Power, supplied 98pc of all British households. As more suppliers have entered the energy market they have lost eight million households to the new entrants over the past five years.
A typical household can save around £330 a year by moving from a standard tariff with a Big Six supplier to a new deal with a mid-size supplier, according to research from Flipper.
Households that remain loyal to their provider are also being hit with an average “loyalty tax” of £250 on average as teaser rates jump up to higher standard variable rates, according to energy provider Bulb.
The energy watchdog Ofgem announced this month that the price cap on variable tariffs will be cut to £1,042 from October 1, its lowest level since it was introduced at the beginning of last year.
This will save more than 15 million households at least £84 a year and help to protect consumers from defaulting to a higher tariff without realising, but people can still save money by switching.
Emma Pinchbeck, of Energy UK, a trade body, said: “Although Ofgem announced a cut to the price cap, it’s still very much worth customers checking they’re on the best deal for them – either by contacting their own supplier or checking across the rest of a very competitive market.”