Ventilation fans should be installed in the bathroom, garage, kitchen and attic. Ventilation fans are usually used in the more odorous and humid rooms of a home in order to make the air healthier and more comfortable and to prevent the growth of mold.
Ventilation fans are also used to protect the walls and keep wallpaper from peeling due to excess humidity. Furniture and floors made of wood can also become warped if there is too much moisture in the air.
Ventilation fans should be installed by a professional so they're set up correctly. If not set up the right way, the fan may funnel excess moisture into other areas of the home.