Choose outdoor patio fans based on the amount of exposure to moisture anticipated in the installation location. Damp fans are ideal for covered patios, and wet-rated fans are ideal for mounting in areas where exposure to the elements is a possibility.
Installing an indoor, dry-rated fan outside can lead to early failure and dangerous conditions. Manufacturers do not use motors on dry fans that withstand moisture. The fan blades often start to droop, rust or break with outdoor installation. Moisture in a dry-rated motor can lead to a short circuit. While damp and wet-rated fans require a larger initial investment, they provide greater safety and longer life.