Roof vents and ventilators are devices meant to exhaust superfluous heat and humidty from the building or structure below. Circulating fresh air into the structure reduces the chance of mold and mildew accumulation, as well as ensuring the comfort of inhabitants. Static roof vents process the airflow exchange with no mechanical action, relying on the fluid buoyancy of warm air. Powered roof vents use a fan or turbine to promote a low pressure zone to withdraw air from the structure. Powered roof vents may be wired into the building's electrical system or solar powered, but both power sources greatly reduce the workload of a structure's cooling systems, yielding energy savings. Common types include: ridge vents, eve vents, dome roof vents, and slantback roof vents.
Turbine roof vent; slantback roof vent; ridge vent
Images credits: Adamson Roofing Ltd.; Applied Energy Products; Cor-a-vent