People have been urged to use caution as several low-temperature warnings were issued for Ireland over the coming days.
The Government has said that an energy supply warning could be made in the next two weeks.
This is due to a drop in temperature causing an increase in demand for energy, while low wind levels are expected to lead to lower energy supplies.
A status yellow low-temperature warning has been issued for all of Ireland between 10pm tonight until noon on Friday, with temperatures expected to fall to minus 4C.
This could lead to “sharp to severe frost” with possible icy surfaces and freezing fog patches, forecaster Met Eireann said.
A snow-ice warning for Dublin and Wicklow will be in place from 9pm until 6am on Friday, while a snow-ice warning will remain in place for Co Donegal until noon on Saturday.
The Road Safety Authority warned that road users should be aware of the dangers caused by a drop in temperatures, and should watch out for black ice.
Concerns have been raised in particular for the welfare of older people who live alone, and for those who are sleeping rough.
During Leaders’ Questions, People Before Profit-Solidarity TD Mick Barry said the looming cold period, coupled with the energy crisis, posed a serious threat to elderly people and families.
“I’m receiving reports of elderly people in my constituency who are not turning on the heat in this cold snap,” the Cork North-Central TD said.
“I’m also receiving reports from working people, family people with kids, who use pay-as-you-go meters.
“They were very concerned that their 200 euro electricity credit will be used during this cold snap and that they will be left in a very tricky situation over Christmas.
“Cold snaps can make or break governments,” he said, expressing concern at the Dail rising for a month over the crucial Christmas period.
Tanaiste Leo Varadkar said: “We’ll allow people to take a few days off to spend some time with their families, maybe five working days.
“But I can absolutely guarantee you that the Government will meet through the recess, at Christmas week and also first thing in the New Year.”
He added that the second energy credit of 200 euro, which excludes VAT, would be paid “during that month” while the Dail is in recess.