How big of a fan? and what power

[Niala]

So you’ll need a minimum of 140 cfm exhaust/intake fan with consideration to let you use CO2.

Hoping that’s helping you @McLovin777

~Al

P.s. Here’s a topic that I create that give you a step by step information

How to calculate the exhaust fan cfm with carbon filter and take in consideration HID lights, temperature and humility, a beginner guide

Here’s how it can be done: Calculating By Room Volume You will find many calculations on the web for sizing a fan for ventilating indoor gardens; however, what many of these calculations fail to take into consideration is the friction loss on carbon filters and increased temperatures from HID lights. So here’s my calculation method which you can use as a guide for sizing an exhaust fan for a growing area (keep in mind that this calculation will give you the lowest required CFM (Cubic feet of a…