is an intake fan needed?

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kjc0314

Well-Known Member
Does it really matter if you have a intake fan? Would passive holes in the room be good enough?
 
TeaTreeOil

TeaTreeOil

Well-Known Member
An exhaust fan is usually more effective(if you only have one fan). You still need intake vents, but they do not need fans.

It depends where the holes are. One in the ceiling, and one lower to the ground would create their own passive airflow.
 
tilemaster

tilemaster

Well-Known Member
depending on ur situation and equiptment..with any HID lighting passive isnt enought generally. a/c or chillers take the need for intake away..but those cost thousands and so do the multipe HID's that are ran with them. Generally u need intake which can be passive and a exhaust to draw that passive air in. but like i said if your lamp is really hot..or ur space really small youll need exhaust and intake. fresh air is ur friend
 
Quickee

Quickee

Well-Known Member
what kinda of lighting are you going to be using..what size is the room? etc..give up some info please
 
Quickee

Quickee

Well-Known Member
waht watts..how many..you prolly should vent it..buck since the room is big..heat prolly wont be that big of an issue..depending on the size of the lamp..but have a lot of fans in there if you dont vent it
 
B

bigbuddy69

Member
An intake fan hepls the outtake fan, it equalizes the pressure in the room , and in turn the intake fan increases the effeciency of your outtake fan, so the anwser is yes. It helps a ton.

However, it is realitive to the size of your grow, and how much air exchange you need. But I have found an intake fan is a very nice thing to have. It will increase your Co2, because its pumping fresh rich air into the room.
 
K

kjc0314

Well-Known Member
bigbuddy69 said:
An intake fan hepls the outtake fan, it equalizes the pressure in the room , and in turn the intake fan increases the effeciency of your outtake fan, so the anwser is yes. It helps a ton.

However, it is realitive to the size of your grow, and how much air exchange you need. But I have found an intake fan is a very nice thing to have. It will increase your Co2, because its pumping fresh rich air into the room.
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well i have an ac unit and a big exhaust fan in the room... if i have an intake fan should it be on all day? and it sohuld be quite smaller than my exhaust correct? im hesitant because during the day the room outside (2nd floor) gets really hot and i dont need all that hot air coming in. Also, what co2 ppm is good for the room to be at and if I test the co2 levels is that a good way of telling if the room is getting enough fresh air?
 
tems

tems

Well-Known Member
kjc0314 said:
well i have an ac unit and a big exhaust fan in the room... if i have an intake fan should it be on all day? and it sohuld be quite smaller than my exhaust correct? im hesitant because during the day the room outside (2nd floor) gets really hot and i dont need all that hot air coming in. Also, what co2 ppm is good for the room to be at and if I test the co2 levels is that a good way of telling if the room is getting enough fresh air?
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My exhaust is on 24/7. My intake is on only during light hrs.I thank randy for that info.

https://www.rollitup.org/grow-room-design-setup/167842-air-handling-4x4x8-430watt-flower.html
 
TeaTreeOil

TeaTreeOil

Well-Known Member
bigbuddy69 said:
An intake fan hepls the outtake fan, it equalizes the pressure in the room , and in turn the intake fan increases the effeciency of your outtake fan, so the anwser is yes. It helps a ton.

However, it is realitive to the size of your grow, and how much air exchange you need. But I have found an intake fan is a very nice thing to have. It will increase your Co2, because its pumping fresh rich air into the room.
Click to expand...
Actually, in my experiences an intake fan can equalize pressure somewhat, but this is not always desirable. Having solely an outtake creates negative pressure(like a vacuum) and air will be sucked in. There is likely to be little if any change if your in/out fans are of equal CFM.

Now then, having two fans both intake or both exhaust would likely nearly double the air flow. Otherwise, as stated, they equalize, and there isn't much if any change to the actual amount of air being cycled.

100 CFM in... 100 CFM out. That's still 100 CFM. One of your fans will basically be redundant.
 
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bigbuddy69

Member
Tea TreeOil I understand your logic.

I felt the same way, but since my exhasut fan can't push out what its rated at becasue of the carbon filter, I need to create more air movement in the room. Basic fans are nice, but the intake really topped it off. I get a -5 degree (or greater) difference with the intake, and thats a good thing for me :-) An air conditioner isn't quite needed.

I have a 10' X 8' room, and I have my exhaust fan on all the time, as it pumps the air through a carbon air filter to keep the smell down. The intake is only on during the day. It gets too cold at night if I leave the intake on 24/7.

I realize everyones situation is different, and an intake fan isn't always a necessity. I have one exhaust fan venting three 1000 watt ventilated horizontal lights, so its pumping some serious hot air outside.

Perhaps its the cool air that the intake brings in thats most benificial.
 
TeaTreeOil

TeaTreeOil

Well-Known Member
Do you filter the intake? If not you're likely forcing a bunch of spores, dust, dander(if you have pets), and who knows what into the room's air supply and onto the plants.

That's one area I would suggest intake and exhaust, if you filter both. Definitely.
 
K

kjc0314

Well-Known Member
TeaTreeOil said:
Do you filter the intake? If not you're likely forcing a bunch of spores, dust, dander(if you have pets), and who knows what into the room's air supply and onto the plants.

That's one area I would suggest intake and exhaust, if you filter both. Definitely.
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So I would also just be fine with having the exhaust 24/7 and passive intake holes around the room?
 
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