What is the primary effect of the stack effect on air movement?

The primary effect of the stack effect on air movement is that it causes air pressures to equalize from the bottom to the top of buildings. The stack effect occurs due to differences in temperature and density between the indoor air and the outdoor air. When the air inside a building is heated, it becomes less dense and rises. As this warmer air ascends, it creates a lower pressure zone at the bottom of the building, prompting cooler air to enter from lower spaces, such as doors and windows.

This process not only helps to move air throughout the structure but also plays a significant role in the overall ventilation and air quality within the building. It highlights the importance of understanding air movement dynamics in building design and energy efficiency, particularly in relation to the placement of air barriers and insulation. Proper management of the stack effect can mitigate the loss of thermal energy and improve the overall comfort within the building.