Incorrect electricity meter clocks are going unnoticed, meaning millions of households on reliant tariffs could be paying too much, consumer group Which? has warned.
The watchdog said its members had come forward to warn that their meter clocks had been showing the wrong time, potentially leaving them “significantly out of pocket”.
About 3.9m UK households are on time-of-use tariffs, such as Economy 7 and Economy 10, which offer customers a lower rate for electricity during some hours and a higher rate for others.
Gary Day, a retired engineer from South Wales, told Which? he had saved himself and three neighbours more than £2,300 after discovering their meter clocks were wrong by several hours.
They were all on time-of-use tariffs with supplier Swalec, which supplies gas and electricity to customers throughout Wales.
Day told Which? magazine: “I have only checked four meters, and every single one of them was wrong. I am horrified that there might be hundreds of others that have these clock errors and don’t realise it.”
He said two replacement meters failed and he was wrongly told his clock would automatically adjust to British Summer Time.His neighbour Andrew Murphy claimed back around £800 after discovering his clock was about three hours out.
Murphy told Which?: “The problem is most consumers don’t go around checking, and we are at a disadvantage because of that.”
Swalec told Which? that staff were not required to check the clocks when they read meters, although if they happened to notice any problems, they were obliged to report them. It said it could not release any information about the scale of similar problems. Ofgem licence conditions say suppliers must inspect meters at least once every two years.