Passive Ventilation

Passive ventilation typically relies on using physical principles like the thermal updraft that naturally results from the tendency of warm air to rise and cool air to sink, and by the effect of cross ventilation, by creating unimpede

d airflow through a building. Many passive ventilation systems rely on the building users to control windows and vents as dictated by site conditions and conditions within the building. The building’s situation and relation to land forms or, for example, adjacent woods, determines the capacity for passive ventilation to be effective in cooling and ventilating a building. Passive ventilation can occur intentionally through the control of air movement through openings such as windows or doors from wind pressure and/or indoor-outdoor temperature differences or through the unintentional or uncontrollable air flow through unintentional openings in the building envelope (infiltration) resulting from wind and temperature generated pressure differences across the building envelope.