Loyal customers are being ripped off by energy companies, a hard-hitting government report has warned.
According to the Competition and Markets Authority (CMA), more than 95% of dual-fuel energy customers are paying more than they would if they switched to another supplier. The savings they'd make range from £158 to £234 a year on their bills.
Like many other service providers, the energy companies offer a range of better deals to new customers, meaning higher prices for those who stick with one supplier.
And it's just not good enough to say that it's the customers' own fault, says Gillian Guy, chief executive of Citizens Advice.
"Loyal customers on standard tariffs, prepayment meter users and those who don't or can't go online to find the best deal are losing out," she says.
"Keeping the lights and heat on are not luxuries. The market is not working if the burden is entirely on consumers to switch for them to benefit from falling wholesale costs."
In the last year, it's been made easier to switch energy supplier, with the process streamlined to take just 17 days, down from five weeks before.
"When it comes to switching, the power is in people's hands to get a better deal and save, says Liberal Democrat energy secretary Ed Davey.
"We've reformed the market so that there are more suppliers, more competition, and a much faster and simpler process to switch. That means millions of people can switch supplier and save hundreds of pounds today."
And the energy companies aren't the only ones relying on our inertia to charge us more - everyone from the credit card companies to mobile phone providers do it too.
Like the energy companies, for example, phone providers frequently switch you from a good fixed-rate deal to a much worse standard variable one when the original contract runs out - and often don't tell you they've done it. In the case of the energy firms, the CMA found, this leaves customers paying around 12% more than they need to.
Similarly, banks rely on customers forgetting when that great credit card deal or high-interest savings rate ends.
The answer is that when signing a fixed-term contract, you should always make a note in your diary of when it's due to run out - and then look for a new deal before the rate goes up.
Another trick, used by insurance companies in particular, is to offer you a new deal at renewal without reminding you of what you were paying before. If you don't have your paperwork to hand, and haven't shopped around, you can end up paying hundreds of pounds more.
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