Depending on where you live, an electric fan might not be a great idea to beat the heat.
In some cases, it might actually hurt your body's effort to cool down.
Australian scientists look at the vital signs of 12 people using fans in both dry and humid heat.
They found that in hot, humid air, fans could help lower core temperatures, relieve strain on the heart, and make study volunteers feel more comfortable.
In hot, dry air, however, there was no cooling effect, nor a decrease in strain on the heart.
In those situations, they say air conditioning is a must.
Several previous studies have concluded that using fans in temperatures of 95 degrees or above can also be harmful.
Electric fans harmful in dry heat, researchers say