Air Changes per Hour (ACH or ACPH) of an air purifier determines how many times the machine can exchange the whole volumetric air from a specific sized room in an hour. For example, an air purifier can make 2 ACH in a 300 sq ft room, which means it takes 30 minutes to clean.
Find your Air Changes Per Hour (ACH) using the calculator below.
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Air Changes per Hour Calculator:
Enter your air purifier’s Clean Air Delivery Rate (CADR) either in cubic feet per minute (cfm) or cubic meter per hour (m³/h), and your room dimensions to calculate the Air Changes per Hour (ACH) of your air purifier.
Here is the formula:
Air Changes per Hour = [(CADR in cfm x 60) / (L x W x H)] per hour