Gary Day, a retired engineer from Abergavenny, has saved himself and three neighbours more than £2,300 after discovering their meter clocks were wrong by several hours. Tariffs such as Economy 7 and Economy 10 offer customers a lower rate for electricity during some hours.
Nearly four million households across the UK are reliant on tariffs, according to the consumer watchdog Which? Mr. Day told Which? "I have only checked four meters and every single one of them was wrong. I am horrified that there might be others that have these clock errors and don't realise it."
Mr Day and his neighbours were all on time-of-use tariffs with Swalec. A spokesperson from the company offered to recalculate any charges for customers whose meter clock is incorrect.
"We will always make sure our customers are not left out of pocket. If anyone suspects their meter clock may be incorrect, or would like us to check, please give us a call on 0800 975 8317."
More top news
A bronze war memorial which was moved from a fire damaged chapel in Aberystwyth seven years ago is now being returned to its original place.
The introduction of a "stickers in windows" hygiene ratings scheme has been a big success, says Deputy Health Minister Vaughan Gething.
One-year-old sheepdog Nell was stolen from a farm on the outskirts of Dolgellau.