Air exchange ratio defines the number of times per hour that a room's total air is drawn through the purifier. Typically a higher number of hourly exchanges reduces the dust contamination level at a faster rate, and will maintain the target dust level for a longer period. As the air filters accumulate dust, the air flowing through the air filters decreases due to the restrictions in airflow. This decrease in airflow can negatively affect the hourly air exchanges to a point where the target dust levels cannot be maintained. PAT purifiers each contain a sophisticated electronic control and monitoring system to recommend when any of the three stages of filter need replacement as well as indicating the system differential pressure.
Airflow patterns are extremely important when selecting and positioning a purifier in a room.
The purifier's intake and exhaust grills should be at least three feet apart, a distance that will ensure that there is no short-circuiting. Short-circuiting is when the purified air is drawn back into the purifier due to the limited space between the air intake and exhaust grills. During installation of a standalone room air purifier it is important to remove any obstacles that might impede the air from exiting the top of the air purifier, travelling along its targeted route, and returning to the bottom of the air purifier. The ideal positioning of a standalone room air purifier is against a wall with the airflow from its exhaust grills directed towards an opposing wall. Home Page Top of Page Model Index Filter Kits PAT provides a kit consisting of the three filter stages.