Energy firms have been warned not to raise Direct Debits for hard-pressed customers who are cutting back on their use.
Suppliers say household use has dropped by around 10% compared to previous years as households use less power.
In a letter published today, Business Secretary Grant Shapps told bosses he expects to see this reflected in monthly payments.
Mr Shapps said he was "disturbed" by reports that Direct Debits are going up despite "huge efforts" to cut back.
It comes as E.ON and the owner of Utility Warehouse said they have seen declines in energy use of more than a tenth.
Mr Shapps wrote in a letter shared on Twitter : "It is critical that consumers are able to manage their bills effectively and direct debit can be an efficient way for families to smooth their energy costs over the year.
"However, I am disturbed by media reports that some consumers are saying their direct debits are going up when they are making huge efforts to reduce their usage to save money at a time when household incomes are squeezed.
"It is in all our interests that when consumers take sensible steps to reduce their own bills, such as reducing their boiler flow temperature or making their homes more energy efficient, that they are able to see an impact in their bills."
The Business Secretary, who briefly held the post of Home Secretary under Liz Truss before being demoted under Rishi Sunak, wrote: "I am very keen that all suppliers find a way to make their systems more responsive to these very positive changes in consumer behaviour and have asked Ofgem to report to me on how this can be achieved."
He continued: "With other costs increasing for households, it is critical that we do what we can to help.
"I am interested to understand how you intend to ensure that your Direct Debit system does not over-estimate charging."
Michael Lewis, chief executive of E.ON, said the company was “seeing reductions of 10 to 15%” compared to seasonal averages in recent weeks.
He told The Guardian : “It’s quite a big effect. We’re analysing our data and trying to understand what’s happening.
"It will likely be people putting the heating on for shorter periods or turning down the thermostat in their home. Those are the two big levers.”
