Hawke's Bay people overpaid for power by more than $8 million last year, according to the Electricity Authority.
A new report on the performance of the residential electricity market in 2015 showed people in Hawke's Bay could have saved $8,854,618 or $135 per household last year by switching to the cheapest deal available.
Hastings Budget Advisory Service co-ordinator Kristal Leach said a lot of clients came to the service with electricity issues at this time of year.
"They often have high power arrears and they might have a disconnection notice."
A disconnection would damage their credit history and make it difficult to find a supplier. It was best for clients on lower incomes or benefits to pre-pay for electricity, because it gave them control over the amount they spent.