Research by household money-saving tool Nous.co found that an astonishing 7 million people, 15 percent of the adult population, have lost out because they have never changed suppliers for gas and electricity.
Consumer champion Greg Marsh has warned that households who have lost out are still paying more than they need to.
Greg, founder and CEO of Nous.co, said: “Having to switch suppliers regularly is a huge pain, which is why so many people have never done it. Even when deals were rife, many households ended up on the wrong one and missed out on big savings.
“We started Nous.co to help people navigate this minefield. Right now, for instance, we can save most households more than £100 on their energy even without signing up to a fixed contract by securing deals most people don’t know about.”
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The analysis of figures from industry regulator Ofgem shows that failing to switch will have cost a typical household £1,050 since 2018.
Supplier switching opportunities have been almost non-existent in the past 18 months amid the UK’s energy crisis.
Greg added: “After more than a year of crisis, I’m concerned inertia has set in and people have got used to sky-high bills.
“Hardly anyone has the time or inclination to spend hours sifting through energy deals.
“That’s why we started Nous – to take on the work of figuring out when to switch and who to switch to for energy as well as other household services like broadband and mobile.”
The research found that households in London, the North East and Scotland are most likely to have been paying over the odds.
In those regions 19 percent have never switched energy supply, compared to the 15 percent UK average.
Glasgow is the worst performing city (25% non-switchers), followed by Leeds (19%) and Newcastle (18%).
Most savvy switchers are in Liverpool (11%), Manchester (12%) and Bristol and Cardiff (13%).
The energy crisis, which escalated as a result of the war in Ukraine, sparked a collapse in energy deals available.
The number of switchers fell from more than 10 million in 2020 to 1.5million in 2022, figures from Ofgem show.