Energy supplier SSE has admitted some of its customers may have been overcharged by faulty meters.
As many as 8,000 customers could have been affected by a manufacturing fault in a batch of Economy 10 electricity meters. After a power cut, the meter clock can move back an hour when the power comes back on.
E10 meters give customers ten hours of off-peak electricity split into three blocks over 24 hours. This means they can get lower rates for their heating and hot water during off-peak times.
Because of the fault, some customers who used electricity during off-peak time could have been charged at the normal rate rather than the off-peak rate.
SSE said it is checking all of the Economy 10 meters are functioning properly and whether customers have been correctly billed.
Jacqui Maxwell, SSE’s Head of Customer Service said: “We’re committing to check each and every meter that could be affected by a manufacturing fault, replacing it if necessary and recalculating the charges for as long as the meter has been in place to ensure that no customer loses out.”
The Scottish supplier will recalculate the charges based on the assumption that 70% of the customer’s units were used off-peak. It said typical E10 meter customers use around 50% off their electricity off-peak.
SSE said it hoped this method should work out “favourably for the vast majority” of customers affected by the fault.