Households who have remained with the same energy supplier for more than 15 years have paid around £3,000 more on their energy bills.
That’s £300 more per year, according to a survey by Energy Helpline which asked more than 2,000 people about the topic.
It found five-years of loyalty have cost 32% of them around £18.7 billion more on their energy bills, than those who switched their supplier.
Around 7% of respondents haven’t switched for between 10 and 15 years and have overpaid between £2,000 and £3,000 more.
A total of 15% have not moved supplier for between five and 10 years and have paid between £1,000 and £2,000 more on their bills.
According to the survey, these results show energy suppliers are receiving an over payment of £5.4 billion per year.
Commenting on the findings, trade body Energy UK said: “If consumers are confident in their energy company, that’s a good thing. A recent government survey shows 63% of customers trust their supplier.
“If however, anyone is not happy with the level of service they receive, there is now over 40 suppliers to choose from offering fantastic deals. This is the time to take full advantage as the process is simple, safe and easy.”