Air Changes per Hour (ACH or ACPH) of an air purifier determines how many times the device can exchange the whole volumetric air from a specific sized room in an hour. For example, an air purifier has 2 ACH in a 300 sq ft room means it takes 30 minutes to clean the room.
To calculate the Air Changes per Hour, you need two things. The first one is the Clean Air Delivery Rate (CADR) in cubic feet per minute (cfm) of the air purifier, and the second one is the dimensions of the room you want to use the air purifier.
Find Air Changes Per Hour (ACH) from the calculator below:
Air Changes per Hour Calculator:
Formula: Air Changes per Hour = (CADR in cfm x 60) / (L x W x H)
If you have the CADR ratings in cubic meter per hour (m3h) format, then convert it into cfm by dividing by 1.699.