Looking for a fan to cool tent.

Skoal

Skoal

Well-Known Member
Tent size is 32x32x not sure on height.

I have a 400 watt MH that runs pretty hot. Can get temps up past 35c.

I bought a shit 4 inch 65cfm booster fan and hooked it up. It does work but not enough. I also just tucked it in a vent port not running any duct work. It cools the tent but not as much as I want.

I’m thinking about a 4 inch inline fan at 195cfm or a 6 inch inline fan at 430CFM.

I don’t want to cool the tent too much or have that much air being sucked out. Would a 195cfm fan keep my temps under 28C? I feel that a 430CFM is going to be way to powerful.
 
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UncleReemis

UncleReemis

Well-Known Member
You're most likely correct. True 195 cfm should produce a powerful enough vacuum from the negative pressure to suit your needs and true 430 cfm would be way too much for a 32" x 32" x whatever. You'll definitely need proper ducting regardless.

Once you reach a certain air exchange rate, there seems to be an equilibrium in tent temps based on ambient temps outside of the tent. So after that point, your focus would be on cooling the room that houses the tent if the temps are still too much.
 
B

Bobby Long Buds

Well-Known Member
I would be thinking a 6” (maybe 8?) fan with speed control or a thermostat(inkbird 50$) to turn the fan on and off. Or both. Then play with it to suit. Every room is different.
Factors that come into play are ambient air temps throughout the year.
Size of passive air intake. Possibility of active intake.
Carbon filters add drag and lower cfm of any fan.
Passive intake holes that are undersized reduce efficiency.
Cooled/open reflectors.
Duct boosters are typically good for active intake not great at extraction especially with carbon filter.
 
coreywebster

coreywebster

Well-Known Member
Skoal said:
Tent size is 32x32x not sure on height.

I have a 400 watt MH that runs pretty hot. Can get temps up past 35c.

I bought a shit 4 inch 65cfm booster fan and hooked it up. It does work but not enough. I also just tucked it in a vent port not running any duct work. It cools the tent but not as much as I want.

I’m thinking about a 4 inch inline fan at 195cfm or a 6 inch inline fan at 430CFM.

I don’t want to cool the tent too much or have that much air being sucked out. Would a 195cfm fan keep my temps under 28C? I feel that a 430CFM is going to be way to powerful.
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It comes down to what your ambient air temps are in the room or basically the air that's coming in and how much temp you can afford to raise by to still be in ideal range.

Check out this chart. Its based on airflow X wattage to give temp rise from ambient.


Always work from worst case scenario , like summer temps and add 20-25% for filter and duct airflow reduction.
 
Skoal

Skoal

Well-Known Member
My grow tent is in my basement. So I’m not worried about it ever getting too warm down there. Even in summer. This is my veg tent. I will not be adding a carbon filter. No need.
 
A

Apalchen

Well-Known Member
You could maybe get away with a 4 inch inline fan DO NOT BUY the vicosun 4 inch fan and filter it’s a crap product. But notice I said maybe. Don’t have to buy it again buy a 6 inch fan with a speed controller or even the infinity ones on amazon that come with temp controller so kicks on and off to keep temps regulated. Also do yourself a favor and match a can 33 to the fan don’t chheap out on fans or filters they are more important than anything else in your grow even lighting. Because if you can’t cool it all you have is an expensive space heater

Just noticed you said weren’t running a filter, so you can get away with a 4 inch inline fan but I still wouldn’t for anumber of reason. Number one being I’ve never wish I had a smaller fan, number two almost everyone expands later and at that point a 4 inch fan is worthless. 6 inch fans are a real piece of equipment that can be used forever and to me the 4 inch are like toys.
 
Skoal

Skoal

Well-Known Member
Apalchen said:
You could maybe get away with a 4 inch inline fan DO NOT BUY the vicosun 4 inch fan and filter it’s a crap product. But notice I said maybe. Don’t have to buy it again buy a 6 inch fan with a speed controller or even the infinity ones on amazon that come with temp controller so kicks on and off to keep temps regulated. Also do yourself a favor and match a can 33 to the fan don’t chheap out on fans or filters they are more important than anything else in your grow even lighting. Because if you can’t cool it all you have is an expensive space heater

Just noticed you said weren’t running a filter, so you can get away with a 4 inch inline fan but I still wouldn’t for anumber of reason. Number one being I’ve never wish I had a smaller fan, number two almost everyone expands later and at that point a 4 inch fan is worthless. 6 inch fans are a real piece of equipment that can be used forever and to me the 4 inch are like toys.
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I doubt I’ll ever grow bigger. No room for it. Don’t smoke a crazy amount of weed. Plan to flower 2-3 at a time and veg 2-4 and then have clones going. Running a veg tent and soon to run a flower tent, with clones separate in a propagation dome.

Those infinity fans look unreal. I’ll probably pick up a 6 inch wth a carbon filter for the flower tent. Having them kick on at certain heat settings is amazing. Removes the need for hooking them up to a timer and would never have to worry about it getting too cold as it’ll go off at a select temp oppose to running till the timer goes off.
 
Coloradoclear

Coloradoclear

Well-Known Member
The moral of this whole thread is to buy "quality" the "first" time. If your budget is tight, Craigslist might be helpful. Price seems a bit low on the infinity . . . One reviewer said the CFM were cut in half when used with a carbon filter.
 
Coloradoclear

Coloradoclear

Well-Known Member
I am still running a Craigslist special, $30, 4" Hurricane lol. Heavy and solidly built. Definitely requires duct muffler!
 
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