How do I use the ACH calculator?

To use our free ACH Calculator, you need the room's volume and the total airflow rate (measured in cubic feet per minute) of your ventilation system. The ACH is calculated using the formula: This formula calculates the air change rate or how many times the air within a room is replaced in an hour.

What is the air changes per hour calculator (ACH)?

With the air changes per hour calculator (ACH) you can determine how often your air device exchanges the air in a room.

How do I calculate air exchange rate (ACH)?

To calculate ACH, you need to know the dimensions of your room as well as the CFM of your air purifier or the exhaust fan. My ACH calculator is the easiest way for you to find an accurate air exchange rate. To use it, enter your room dimensions, including the length, width, and ceiling height.