A box fan is a device used to circulate air in order to keep the air cool or to eliminate odors. A box fan consists of rotating blades encased in a square covering. The covering of the box fan has several open slots on both the front and the back in order to allow air to be drawn in from one side of the fan and to exit through the other.

A box fan is typically used in residential homes in order to help keep a room cool. Unlike central air conditioning, a box fan can only keep one room cool, rather than the entire house. In addition, the entire room may not be maintained at a comfortable temperature if it is too large for the capacity of the box fan.

Many homeowners also choose to place a box fan in an open window, similar to an air conditioning unit. If the home owner places the box fan in the window so the front faces outdoors, the box fan will draw warm air out from inside the home. If the homeowner places the box fan with the front facing inside, the fan with draw in air from outside. Although the outside air may be warm, a box fan still typically creates a feeling of cold air because it forces the air to move and forms a breeze.

A box fan may also be used in a home simply to help circulate the air and prevent it from becoming stagnant. Similarly, a box fan may be placed in a wet basement or next to a freshly mopped floor in order to aid in drying.

Unlike a pedestal fan or a tower fan, the box fan remains low to the ground because it is not elevated in any way. Typically, the box fan is placed on a floor. However, this can fail to provide the desired circulation since the fan is so low to the ground. Therefore, some box fan owners elect to place the fan on a table on other piece of furniture in order to elevate the fan and provide better air circulation.