Ventilating, also an important addition to HVAC, consists of the systems that exchanges, replaces, and filters existing indoor air in order to create a higher indoor air quality. Rooms in the home such as bathrooms use a more mechanical form of ventilation in order to reduce humidity and odors, while items such as ceiling fans seek to lower perceived temperatures and draw in fresh air through an open window. Your central air system also most likely uses ventilation in its process and provides high air quality through filters that eliminate and capture dust, mold spores, and other indoor allergens.