Fears are are rising that number will rise in the coming months as electricity credits, which have been a feature of every budget since 2022, are coming now over.
Over 400,000 customers are currently behind on their energy bills.
It's feared the high level of arrears could become worse as government energy credits issued in recent budgets have now come to an end.
The ESB has confirmed that 275,000 residential electricity customers were behind on their payments in the three months to November.
While a further 164,000 domestic customers owe money to their gas supplier, according to Commission for the Regulation of Utilities.

In total, it means that about 440,000 residential electricity and gas accounts are behind in payments.
Fears are are rising that number will rise in the coming months as electricity credits, which have been a feature of every budget since 2022, are coming to an end.
Anyone who's struggling to pay their energy bills is being advised to contact their supplier as soon as possible.
The Money Advice and Budgeting Service, MABS, says it's important to get in contact with your energy supplier to avoid disconnection.
Karl Cronin from MABS, says a payment plan can be put in place to help you get back on track.

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