A ventilation system is a setup designed to circulate air within a building, ensuring a supply of fresh air while removing stale air. It helps maintain indoor air quality by controlling humidity, temperature, and the presence of pollutants. Common types of ventilation systems include natural ventilation, which relies on windows and vents, and mechanical ventilation, which uses fans and ducts. Proper ventilation is essential for health and comfort, as it reduces the risk of mold growth and improves overall air quality. In commercial buildings, HVAC systems often incorporate ventilation to regulate air flow and temperature effectively, enhancing the environment for occupants.