What is Cross Ventilation?

Posted by Ian Lachut

Oct 17, 2016 11:43:00 AM

What You Need to Know About "Cross-Ventilation".

Cross ventilation (also called Wind Effect Ventilation) is a natural method of cooling. It has quite literally been used for centuries. The system relies on wind to force cool exterior air into the building through an inlet (like a wall louver, a gable, or an open window) while an outlet forces warm interior air outside (through a roof vent or higher window opening). Modern natural ventilation systems help increase the flow of cool air coming in and assist the hot air going out. This increases building air flow naturally.

Knowing how the fresh air circulates within a structure. around the people inside, and through its openings is crucial to determining how to optimize cooling and improve air quality. This can only be find by looking at the building's inlets and outlets. 

Understanding the Dynamic of Airflow Through Inlets and Outlets


A window or door’s orientation to the direction of the wind will determine the amount of air flowing through the space. Usually, an inlet only works if the direction of the wind flow is in the range of negative forty-five degrees to forty-five degrees to the surface (A ninety degree range around the opening). Placement of air vents and even the placement of the building itself, is often made with consideration of this air movement.

When designing a cross effect natural ventilation system, the area of both the inlet and outlet must also be considered.  The amount of heat removed from a facility is directly affected by the vent's inlet and outlet areas. If the inlet and outlet areas are large, then more air can travel through, meaning more heat can be removed. If the inlet area were greater than the outlet area, this would impede effective ventilation. More air would be coming in than could effectively go out, creating an unbalanced system. An equal amount of airflow volume going into a building as exiting the building is ideal.  

Tips for Cross Driven Wind Ventilation

mv_cross-ventilation.pngWhen designing a ventilation system that utilizes cross ventilation, the direction in which the window blows is the first concern.  Knowing the wind direction (at various times through the day, and during the year) will help determine where inlet and exhaust vents can be placed.

Furthermore, special equipment can help to increase the effectiveness of a cross ventilation system. Products such as specialty wall fans can increase the movement of air across the work floor and through a building. Alternatively, non-powered options such as wall louvers and natural ventilators, are designed to exploit the natural movement of air and increase air movement through a space without any electricity.

Utilizing principles of ventilation design (like Cross ventilation) for over 50 years, Moffitt Corporation is one of the most trusted names in ventilation. Moffitt designs ventilation plans, manufactures ventilation equipment, and even installs ventilation systems. This turn-key approach provides Moffitt with a top-to-bottom experience that helps it get the most out of a natural ventilation system, and put them to work for your building.


Topics: industrial ventilation system, Wind Ventilation, natural ventilation designs


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