I'd refer to StinkyAttic's post regarding the size of your intake. As far as pulling air in? If you have a sealed enclosure (grow tent, box, cabinet, etc.) and you mount an exhaust... you will not need a fan to "pull" air IN. People do use them (referred to as Active Intake) depending on their situation... but you should be ok starting out. Since the space is sealed, the only way your exhaust can pull air OUT is by giving it an open source (i.e. a big hole in the side :jointsmile

I'm kinda confusing myself now. Either way, back to the bowl analogy :hippy:

The clogged bowl = Your sealed grow space
Finger over carb = No passive intake in grow space
Your lungs = Exhaust fan pulling air through

You try to inhale... but your finger is blocking it. You move your finger slightly... a little air comes through, but not enough. You completely remove your finger... total airflow :thumbsup:

Now, would you need a small fan where the carb is to push the smoke/air into your lungs?
- Probably not... but with larger spaces, where negative pressure is more difficult to maintain, it can help.
Woah... I'm losing myself now.
As far as the a/c air?? Well, I don't even have a/c in my place... and my box temps are about 79 during the day and maybe 60 at night? Not sure about that night temp because I just flipped to 12/12. Haven't had too many "nights" to build an average from.

But yeah, check out Stinky's stickies... and the grow room set-up sticky by Rhizome. Lots of reading, but it's sooo worth it!! :stoned: