Energy suppliers owe £1.3 billion to around 11 million UK households, who have maintained surplus credit in their accounts despite the unusually cold winter.
Those in credit are owed an average of £121 each, according to new research from price comparison website Uswitch, and one in ten is due to receive a windfall of more than £200.
The survey of more than 2,000 customers indicated two possible causes for the persistence of surpluses, the first being that more than two-thirds of respondents (69 per cent) took action to reduce their energy usage over the winter.
Almost a third (31 per cent) said they turned down their thermostat, whilst roughly a quarter (24 per cent) lowered the temperature of individual radiators. Over a fifth (22 per cent) only used their heating on especially cold days.
The poll suggested the high level of credit could also be the result of suppliers estimating bills due to a lack of up to date meter readings. One in ten respondents said they provided a meter reading less than twice a year, and a further 5 per cent – the equivalent of 1.4 million households – said they had never submitted one to their supplier at all.
Another finding of the survey was that many companies are still failing to automatically reimburse customers, with more than half of bill payers (54 per cent) having to chase their supplier for a refund.