Window fan
From Wikipedia, the free encyclopedia
A window fan is a fan designed to be placed inside the frame of a window. Window fans have been used for many decades to maintain comfortable temperatures and ventilation within one's home.
[edit] Design and operation
Window fans are designed to fit medium or large sized windows and have expandable side barriers to cover the entire window opening. Most units have either one large sized bladed fan, or two small sized bladed fan units mounted side by side. Rarely, some window fans have used a blower wheel, which is similar in appearance to a hamster wheel.
Most window fans have 3 speed electric motors. Some allow the motor direction to be reversed electrically via a switch, allowing either fresh air to be drawn in from the outside, or inside air to be blown outside. Fans with 2 motors typically have separate controls for each motor.
Manfacturers have added features to their models over the years. Some fans contain thermostats which will turn the fan off if the temperature drops to a certain point, or adjustable grilles to direct the flow of air in a particular direction. Other fans offer sophisticated electronic features such as remote control, automatic shut off timers, or variable speed motor controls.
