A roof-mounted fan in HVAC systems is a type of exhaust fan installed on the roof of a building, used primarily for removing stale, hot, or contaminated air from inside the building to the outside. These fans are essential in maintaining good air quality and proper ventilation, especially in industrial or commercial settings where air might be contaminated with smoke, fumes, dust, or other pollutants.

Roof exhaust fans are highly effective in ventilating buildings, particularly in removing heat, moisture, and air contaminants. By being positioned on the roof, these fans take advantage of the natural tendency of hot air to rise, efficiently extracting it from the building. This placement also allows for the direct expulsion of polluted air at a high point, far from occupants and less likely to re-enter the building.

The lifespan of an exhaust fan can vary depending on its quality, usage, and maintenance, but typically, a well-made exhaust fan can last between 10 to 15 years.