Question

The condition of the air changes from day to day and even hour to hour​

Answer 1

Answer:

ACH = CFM x 60 / (Area x Height)

ACH = CFM x 60 / (Area x Height) In order to calculate air changes per hour, we have to translate that into hours. Hence the multiplication with 60 in the equation above. The volume of a room is simply calculated by length*width*height