A recent study of New Zealand children has found that 50% are sleeping in bedrooms that are too cold.
The study, carried out by researchers BRANZ and the University of Auckland, included around 2000 New Zealand children.
The study asked children to spend two days collecting temperature and humidity information at home and school.
The results made for sober reading. Around 1000 children going to sleep in bedrooms that were too cold – at or below 19C. In some houses the temperature dropped to under 4C by the morning.
A further 13 percent slept in rooms that were too hot or humid, with the hottest bedrooms reaching more than 34C.
University of Auckland Professor of Child Health Susan Morton said the best indoor temperature was between 19C and 25C.
Children living in poverty were more likely to live in houses with temperatures outside of that, and had poorer overall health.