Air Change Rate

The Air Change Rate calculator computes the number of times per hour the air in a space changes based on the flow rate of fresh air (q) and the volume of the space (v).

INSTRUCTIONS: Choose units and enter the following:

• (q) This is the flow rate of fresh air into the space
• (v) This is the total volume of the space (e.g. volume of a room)

Air Change Rate (n):  The calculator returns the change rate in changes per hour.  However this can be automatically converted to compatible units via the pull-down menu.

Ventilation Calculators

• Air Change Rate
• Ventilation Rate per Person

The Math / Science

The formula for Air change rate (air changes per hour) is:

    n = q / v      

where

•     n = air changes
•     q = fresh air flow through the room (Cubic Feet per Minute,  cfm)
•     v = volume of the room (Cubic Feet)