The World Health Organization advises peopleto not relytoo much on electric fans when temperature rise above 35 ° 100 ( 95 ° F ) and the US Environmental Protection Agency ( EPA ) powerfully propose against them at temperatures over 37 ° C ( 99 ° F ) .
Researchers from the University of Sydney were curious to do it if these guidelines had any scientific championship . In a small report involving 12 healthy male volunteers , they find that the advice look to be too clean - deletion and that the existent exposure is more nuanced . The squad found that in surroundings that were very hot and humid , fans were more beneficial that in juiceless and hot surround . The findings are reported in theAnnals of Internal Medicine .
The team used a measurement known as the heat energy index , which combine tune temperature and humidness to furnish a parameter for what a temperature “ feels like ” to human being . The EPA put forward that using electric fan when the heating exponent is higher than37.2 ° C ( 99 ° F)can actually increase the heat accent a person is experiencing .
The data collected from the 12 player prove that in red-hot , humid conditions , fan were still effective at reducing magnetic core physical structure temperature up to a heat index of 56 ° C ( 133 ° F ) . When the heat was dry , however , the cut - off dot was much lower at a heat index of 46 ° C ( 115 ° F ) .
“ Our effect indicate that under environmental conditions that stand for the vast absolute majority of flush heatwaves in the United States and Europe fan should be recommend and the guidelines issue by most public health government are unnecessarily materialistic , ” senior source Associate Professor Ollie Jay said in astatement . “ It is only when the air temperature is very high and humidity is very low that fans are detrimental , which can be seen in arid atmospheric condition such as Phoenix or Las Vegas in the US , or Adelaide in South Australia . ”
The 12 men that took part in the study were placed in a elbow room for two hours where the conditions of sealed retiring heatwaves were recreate . The July 1995 Chicago and July 2017 Shanghai heatwaves dish as models for the hot and humid scenario . Meanwhile , the California heatwave of July 2018 was used to create the hot and ironical scenario .
grounds that fans can be used at high-pitched temperatures is good news for the many that ca n’t afford air conditioning but the team stresses that this is a limited cogitation and bombastic ones are necessary to confirm the results .
