Cooling Fans

Fans are often used to move air around within the house making occupants feel cooler. In this mode of operation, they do not actually cool the air. The moving air causes moisture on the skin to evaporate taking with it heat. The cooling effect of moving air is directly related to the speed of the air, which increases the body's evaporative cooling. Fans are also used to move hot inside air out of the home so it can be replaced with cooler, outside air.

Compared to refrigeration units, fans are inexpensive to purchase and use very little energy. For these reasons, most homes in this country use some form of fan cooling. Systems that rely on the movement of air include natural ventilation through open windows, window fans, portable fans, ceiling fans, whole-house fans, attic vents, and passive ventilation.




Ceiling Fans

Ceiling fans are generally more expensive than portable fans, but like portables, they produce a cooling effect by moving air across the surface of the skin, making people feel cooler. Ceiling fans should only run when someone is there to appreciate their cooling effect. When no one is in the room, keep ceiling fans off.

Ceiling fans are usually mounted at the center of the room where the room's light fixture would normally go. For this reason, they often contain their own lighting fixture just below the fan blades. Lighting is placed below the blades because lights above them will appear to flicker psychedelically when the fan operates.

If you are planning to purchase a ceiling fan, be sure to get one sized properly for the room. Do this by measuring your room area (length times width) and looking for a fan with the appropriate fan diameter.

Room Area
(sq. ft.)
100
150
225
475
400+
Minimum Fan Diameter
(inches)
36
42
48
52
Two Fans

Most ceiling fans offer reversible operation; they can blow down in summer when the breeze will create a cooling effect, and up in winter to circulate warm air that has risen to the ceiling. This feature is particularly advantageous in rooms with high ceilings that trap warm air during the heating season.