ventilation intake

It is often said that the intake ole should be twice as large as the exhaust hole
Why is this?

I'm noticing my fan is moving more air from the end of the e haust when I open additional intake holes.


If there is two much intake, air isn't drawn from the outside in as much? Is this the case?

large intake for passive, smaller for active...

You want a slight negative pressure in the grow room, preventing odor seepage, and ensuring air rotation via the intake>exhaust.

You are God, you control the winds.. air seepage is like holes in the O3 layer...

If it straight up seems like your exhaust gasps when you open another intake, go ahead n do it. You want SLIGHT negative pressure, but you dont want the fan to burn itself out trying to vacuum seal the room, hehe.

If this is a tent, you will see the walls slightly and slowly pull in and tight when you seal it up, if it does it quickly, open another. If it stays kinda saggy n limp, close one off.... If its got them velcro borders, put it on part way if needed.... the only thing you gotta remember is you want just a 'little' more pull out than in.

(alternately, consider a fan speed controller to dial it in if you arent having heat issues)

What about putting duct booster fans in a row? How far should they be spaced? My room is heating up, do I need insulated ducting?

Where else would the hot air be coming from?

It gets piped out the window