I have a grow tent that's 4'9x4'9x6'7 with a total of 148.5 cubic ft Question 1: will a 600 cfm exhaust fan be good to vent it properly or is that too much of a overkill? What would be the desired cfm for that size of tent? Question 2: say I do use the 600 cfm fan, what size should my carbon filter be to eliminate all odor? Question 3: say I did use the 600 cfm fan for exhaust, would a intake fan blowing air into my tent with a fan with a cfm rating of 300 create the negative pressure I need? Question 4: I only have one place I can exhaust my air so I have to hook everything up to the same ducting line, would this setup be okay and will that one fan be able to exhaust all the air through this setup? Carbon filter>fan>ducting>light>ducting to out of tent>ducting to ceiling to attic. Is that a ok setup? Or should things be placed or hooked up differently? The ducting won't be all that long all in all and few bends but it will go vertical when it leaves tent to go to attic.
600 cfm is probably overkill for a room that small, but it doesn't hurt to have a little more than needed. As for the cfm of the room, I can't recall the formula right off hand. you could get a 4" carbonair filter, I put the filter in the room, and the fan outside the room, pulling air through the filter, exhausting outside the tent. should take care of all odor you dont need a 300 cfm intake fan, that's way too much. my room is5 x 5 x 8 and I successfully use a 100 cfm fan for exhaust with a4" filter. i have a cheap little inline duct fan for intake and it works great, no odor but does the job well. that 600 cfm fan should be strong enough to exhaust everything that you mention in that tent, i would think.
well I was told that I would have to replace the air at least 3 times a minute. So my cubic feet is 148.5. So I have to replace at least 3 times in a minute. Wouldn't that mean my fan would at least have a cfm rating between 450-500? And with that fan wouldn't that mean I would need the same size carbon filter? And with the fan outside of the tent would it still successfully pull air through the carbon filter and cool the light?
I am pretty sure that it was 3-5x per hour, not minute, but I might be wrong. I found this info: How to size your exhaust fan There are many calculations on the web for sizing a fan for ventilating grow rooms; however, what these calculations fail to take into consideration is the friction loss on carbon filters, increased temperatures from HID lights and CO2, etc. The following calculation can be used as a guide for sizing an exhaust fan for a growing area (keep in mind that this calculation will give you the lowest required CFM required to ventilate the grow room): Step 1 – Room Volume First the volume of the room needs to be calculated. To calculate multiply length x width x height of growing area e.g. A room that is 8' x 8' x 8' will have a volume of 512 cubic feet. Step 2 – CFM Required The fan should be able to adequately exchange the air in a grow room once every three minutes. Therefore, 512 cubic feet/3 minutes = 171 cfm. This will be the absolute minimum cfm for exchanging the air in a grow room. Step 3 – Additional factors Unfortunately, the minimum cfm needed to ventilate a grow room is never quite that simple. Once the grower has calculated the minimum cfm required for their grow room the following additional factors need to be considered: Number of HID lights – add 5% per air cooled light or 10-15% per non-air cooled light. CO2 – add 5% for rooms with CO2 enrichment Filters – if a carbon filter is to be used with the exhaust system then add 20% Ambient temperature – for hot climates (such as Southern California) add 25%, for hot and humid climates (such as Florida) add up to 40% hope this helps! like I said, I've been successfully growing in a 5x5x8.5 room with a 100 cfm fan and a small inline duct fan bringing in air from my basement.
yeah that's the thing I don't get. Is it replace the air 3-5 times a minute or hour or every 3 minutes? I keep hearing different things and I don't wanna buy my stuff until I kno exactly what I need. Your room is 212 cubic ft so I don't understand how you can use only a 100 cfm fan. That wouldn't be enough. You wouldn't even be replacing ur air once a minute. Does anybody kno?
I would say your room is relatively small compared to some i've seen, and a 600 cfm fan is pretty big, whether or not my fan is big enough would really only be determined by what I yield, and I just had a 7 oz. bagseed plant harvest after it was dried, so I'd say my fan, although could be better, is good enough!
i believe u it works. im juss trying to get a solid answer on how to figure out the cfms i need for my size room. i juss keep hearing different things