Households are facing increased heating, power and phone bills after weeks of confinement with appliances running round the clock.
Bin collection costs could also rise with waste companies recording volumes of household rubbish up by 20pc-30pc.
Support groups are now urging consumers to watch their usage of all utilities and check if they are on the best package or tariff for their needs.
While disconnections from gas and electricity supplies have been temporarily halted, advisers are warning that bills will still be mounting.
Michelle O'Hara, regional manager with MABS (Money Advice and Budgeting Service), said for many people the new financial realities would sink in with the arrival of utility bills in the next few weeks.
"We would encourage that you pay what you can. Deferment of payment is not free money. It will still more than likely have to be paid," she said.
Eirgrid is reporting a 7.5pc drop in electricity demand nationally but that reflects the shutdown of much industry and business. By contrast, energy use at home is rising as weekdays become more like weekends when residential demand is typically higher.
Siddharth Joshi, of the Energy Policy and Modelling Group, at University College Cork, said the full implications would take time to emerge.
"There is a change towards the weekend pattern and there is a logic behind this because everybody is at home," he said.
"The bills will shift for sure because we are using more heating at home, we are cooking more, we are using lighting, our laptops are on and at the same time there is a wifi system that is on 24-7. Plus phones are being charged, people are watching TV more and drinking more tea."
Electric Ireland, which cut prices for dual fuel customers last week, said it understood that consumer habits had "changed radically" and this could cause difficulties for customers. "We continue to monitor the situation closely," it said.
Both it and Bord Gáis, which is cutting dual fuel prices from next month, said they were committed to working with customers to resolve any difficulties they had.
Phone and fuel bills are another source of worry, however. Celine Clarke, of Age Action, said while the fuel allowance had been extended by four weeks, 70pc of pensioners did not qualify for it.
She said also older people were often on old phone packages with call limits that were costly to breach.
"The last thing we want is that older people in isolation would be afraid to use their phone because of the cost," she said.
"If it's possible to check what package you're on and see if it's the best fit for you, now would be the time to do that but 55pc of over-65s are not online and it can be hard to get that information."
The Society of St Vincent de Paul (SVP) has called for a moratorium on phone and internet disconnections, and also wants time limits and usage caps lifted.
Kieran Stafford, SVP president, said he was particularly concerned for people alone in isolation and children trying to continue school work.
"We are asking that suppliers engage proactively and compassionately with customers who may face large bills in the coming weeks," he said.