Thermodynamics

• A hot air balloon exemplifies the concept of hot air rising.hot air balloon image by Vasiliy Koval from Fotolia.com
  
  As air temperature increases, air molecules move further apart, and the air becomes less dense. This is why hot air rises. In winter, set the ceiling fan to rotate at a low speed in a clockwise direction. This pulls cold air up from the floor and pushes warm air down around the perimeter of the room.
  
  

Sweat and Evaporation

• Ceiling fans help lower body temperature.ceiling fan image by Adrian Hillman from Fotolia.com
  
  Sweat evaporation cools your body. Ceiling fans blow air across your body increasing the rate of evaporation and making your body cooler. In summer, set the fan's blades to spin in a counterclockwise rotation to blow air down. Setting the fan speed faster increases the volume of air flow, which improves evaporation and cools your body more.
  
  

Humidity

• Ceiling fans don't cool as well in a humid room.rotating ceiling fan image by Yali Shi from Fotolia.com
  
  Ceiling fans do not remove humidity. Humid air contains more moisture, resulting in decreased evaporation. The cooling effects of the fan will not be as great in a humid room.