What is ACH for an Air Purifier?

ACH or ACPH stands for Air Change Per Hour. ACH is how frequently an air purifier can clean the air from a specific sized room in an hour. For example, 4 ACH for 500 square feet size room means it filters the air of that room 4 times per hour, or it requires 15 minutes to clean the air from the entire room. If you increase the room size, then you will get lower ACH and vice versa. Calculate the required air exchange rate with our advanced ACH calculator to choose an air purifier.