physics

There seem to be some common misconceptions about the thermodynamics of fans going around. Running a fan in a room will not cool the room down. In fact it will heat it slightly, as the electrical power going into the fan (on the order of 50-70 watts for a typical standing room fan) will almost all end up as heat. The moving air from a fan will cool people down, by speeding up evaporation from the skin and the cooling associated with that (heat is transferred from your skin into the water as it evaporates), but it makes no sense to run a fan in an empty room. more