Air changes calculator to determine the room CFM

Calculate precisely the cubic feet per minute (CFM) required to replace the air in your grow room, based on the fact that your grow room's air need to be renewed at least once every 5 minutes.

Consider this as the minimum requirement, add 25% to match duct resistance and add another 25% if you use carbon filters and excessively long ducting or if there are many 30 degrees or higher bends in your duct line.

*Note that this method is not applicable to rooms with supplemental CO2.