How do I size my fan and shutters system?![]() 1. The first thing that you need to determine is the amount of air required. This is stated in CFM (Cubic Feet of Air per Minute). 2. Use the following formula to determine the CFM required for your greenhouse: CFM = Length x Width x 12 Example: Greenhouse 12' wide and 24' long requires 3456 CFM (12 x 24 x 12) 3. Reference the above table. Select the appropriate combination of fan(s) to achieve the necessary CFM rating. Be sure to match the total CFM output for your exhaust fan(s) to the CFM ratings for your Inlet Shutters. Click here to view accessory sizing table Click here to view fan installation detail |