"Exhaust Fan" Since it is important, then the fan will install even more important, when the fan is installed, the ventilation duct to the shortest and most direct way to enhance the ventilation effect. Fan mounted directly mounted on the ceiling, attic ventilation duct straight through to the roof, the indoor moisture and odors directly exhausted to the outside on the pass. In this way the efficacy of ventilator installation is the most ideal. Some bedroom fan mounted on the wall, no doubt, can be directly discharged outside the moisture, but the warm and moist air to rise because of its efficacy can not compare the effect of the installation on the ceiling. Therefore, when conditions permit, the fan should be mounted on the ceiling in order to achieve more satisfactory results.