Why is an intake fan important for a grow tent

cannabiscrusader

Well-Known Member
The fresh air will come in passively through any open vent when the exhaust fan is running. The negative pressure in the tent creates a vacuum that draws in the air from outside if the tent. Sometimes air is not exchanged quickly enough and there is humidity build up. This leads to pm and mold problems. As long as the ambient rh in the room where the tent is located is in range, then either a larger exhaust fan is needed, or you can add an intake hooked to a humidistat.
 

itsaliveterps

Active Member
The fresh air will come in passively through any open vent when the exhaust fan is running. The negative pressure in the tent creates a vacuum that draws in the air from outside if the tent. Sometimes air is not exchanged quickly enough and there is humidity build up. This leads to pm and mold problems. As long as the ambient rh in the room where the tent is located is in range, then either a larger exhaust fan is needed, or you can add an intake hooked to a humidistat.
I want to buy a ec5 controller
 

MissinThe90’sStrains

Well-Known Member
It’s what plants crave. Stagnant air and high humidity make a favorable environment for things like plant diseases and mold/mildew. You want circulation and ventilation, and in a non-closed system, extraction too.
 

fanya

Well-Known Member
For my set up, a passive intake wasn't enough. So I added an intake fan on the same controller as the exhaust fan and have the intake run one step below the exhaust. Works really well.
 

UnknownRemedy

Well-Known Member
I have had no problems in a closet with some open air holes in my tent and just an exhaust fan that goes for 5 minutes every 30.

But I'm in a 2x2.5x6 so don't mind me:bigjoint:
 

fanya

Well-Known Member
Wow.. I was imagining something huge.

So how come you need the intake?
Sealed space or something?
I don't run sealed because the only way I have to cool the room is through the intake room; but, I suppose it could be considered sealed, with the door closed the only place for air to reasonably go in would be the intake. Every joint is caulked, including the floor to trim joint.

Even with the exhaust fan running at full, the passive intake wasn't keeping up with the cooling needs of the room running CMH when the intake room had 70/71* air. The active intake solved that problem and the exhaust fan runs much lower too. The fans ran slower too once the cold weather came. Need the CMH for the cold months, have to help cool it some with faster moving air in the hot months.
 
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