Fan Size for 4.5'x4.5'x7.5' Tent

[The Phantom]

I'm fairly set on getting an AC Infinity T4 fan and using a 6" carbon scrubber reduced to 4" for my tent. I have 3 tents, this is relevant because all 3 need ventilation. I live in a very dry environment, my max rh is 45% for just a couple days at a time for 2 months, otherwise it's around 0-10%. I'm moving the drivers for my LEDs outside of my tent to reduce the heat in the tent even further. This fan will probably only run on the medium setting most of the time with an occasional increase for humidity or temp at lights on/off, or so I think.

That's why I'm here asking this. Do you think this is under sized for my requirements? I know some will say that the T6 model is only $40 more, just get it to be safe. This is where the 3 tents part matters, I don't feel like spending an extra $120 on added insurance I may never need. At that point I would almost consider a S4 as a second exhaust or as an active intake.

Does anyone use a 4"exhaust fan on at tent this size? What do people use for fan size? Are there other brands as reliable, quiet, efficient, and reasonably priced exhaust fans as AC?

 

[Rexer]

I'm fairly set on getting an AC Infinity T4 fan and using a 6" carbon scrubber reduced to 4" for my tent. I have 3 tents, this is relevant because all 3 need ventilation. I live in a very dry environment, my max rh is 45% for just a couple days at a time for 2 months, otherwise it's around 0-10%. I'm moving the drivers for my LEDs outside of my tent to reduce the heat in the tent even further. This fan will probably only run on the medium setting most of the time with an occasional increase for humidity or temp at lights on/off, or so I think.

That's why I'm here asking this. Do you think this is under sized for my requirements? I know some will say that the T6 model is only $40 more, just get it to be safe. This is where the 3 tents part matters, I don't feel like spending an extra $120 on added insurance I may never need. At that point I would almost consider a S4 as a second exhaust or as an active intake.

Does anyone use a 4"exhaust fan on at tent this size? What do people use for fan size? Are there other brands as reliable, quiet, efficient, and reasonably priced exhaust fans as AC?

Hey Phantom! I think a 4" fan would be way too small for your needs. Is your ventilation exhausting into lung room, or do you have additional ducting outside the tent?

I actually bought a cheap 8" fan and have it reduced down to 4". I got a lot of bends and long ducting to exhaust to outside the house, the 8" for me had the torque needed, and it's easier to dial a fan down, then run full tilt on it (which reduces life span).

Those AC Infinity fans look pretty sweet, and I'm rather new to all this so my response is more just a "food for thought", hope it helps!

 

[The Phantom]

I'm currently getting by with two small Walmart desk fans zip tied into my exhaust openings and they are having no issues with maintaining heat and humidity, which is why I think I can get away with a nice 4" fan. I currently only have a slight heat issue, nothing crazy just a few degrees above ideal but with the LED drivers inside the tent still. I think most, if not all, will be resolved when the drivers are moved outside the tent.

I'm only now wanting to buy something to replace the two fans plus something to help with odors. I just don't want to spend an additional $40 on a 6" fan that only runs at 50% vs a 4" at 90%+. If I only had one tent to equip I'd go straight for the 6" but since it's for 3 tents, it changes things.

 

[The Phantom]

Is your ventilation exhausting into lung room, or do you have additional ducting outside the tent?

It will be venting right into the room, not expecting any, if at all, additional duct length or fitting/bends, all about that straight shot.

 

[Rexer]

I'm currently getting by with two small Walmart desk fans zip tied into my exhaust openings and they are having no issues with maintaining heat and humidity, which is why I think I can get away with a nice 4" fan. I currently only have a slight heat issue, nothing crazy just a few degrees above ideal but with the LED drivers inside the tent still. I think most, if not all, will be resolved when the drivers are moved outside the tent.

I'm only now wanting to buy something to replace the two fans plus something to help with odors. I just don't want to spend an additional $40 on a 6" fan that only runs at 50% vs a 4" at 90%+. If I only had one tent to equip I'd go straight for the 6" but since it's for 3 tents, it changes things.

After reading that, I'm kinda jealous man....I may just need to give LEDs a better chance!

It will be venting right into the room, not expecting any, if at all, additional duct length or fitting/bends, all about that straight shot.

You might just be fine then with 4 inch. That said, Ive always been a fan (honestly, no pun intended) of up stepping minimum requirements, "plan for the worst and all your surprises will be good ones". In the end my friend, its more a planning for the unexpected vs dealing with things as they happen. If you truly feel fine with a 4" and sounds like you would be just fine, then go for it.

None of it is meant to sound condescending, only good conversation on your choices....hell you most likely know more then me on it

 

[Apoc]

With 3 tents a 4" is a waste of money. Grab a 6" and reduce down to a 4" carbon filter if you want to save money.

Looks like you already made up your mind so feel free to ignore the communities massive combined knowledge.

 

[013]

Hey Phantom, wonder if you could rig up some 6 inch T fittings and share 2 of the big cloud line T6’s sucking air from inside of 3 tents? Even on low setting you would have more throughout & efficiency

 

[TorturedSoul]

Grab a 6" and reduce down to a 4" carbon filter if you want to save money.

And take the chance of "outrunning" the carbon filter if he turns the fan up, lol? I'd want my filter's rated capacity to be higher than the maximum rated flow of my fan.

I'm only now wanting to buy something to replace the two fans plus something to help with odors. I just don't want to spend an additional $40 on a 6" fan that only runs at 50% vs a 4" at 90%+.

Are you worried about noise? I'm guessing that the smaller fan, spinning at a higher RPM, will make more of it.

 

[TorturedSoul]

BtW, want to trade, lol? This past week, it's been a race to 100 here between the temperature and the relative humidity. Sweat doesn't evaporate, it just drips. I'd love to be able to use evaporative cooling devices.

 

[The Phantom]

Looks like you already made up your mind so feel free to ignore the communities massive combined knowledge.

Woah, not sure where this is coming from but it's definitely warranted here, bud.

With 3 tents a 4" is a waste of money. Grab a 6" and reduce down to a 4" carbon filter if you want to save money.

Yes 3 tents, each with their own 4" exhaust fan. I'm also not sure why you would want to reduce any piping or fitting smaller than your fan unless the purpose is to increase velocity and decrease flow.

Hey Phantom, wonder if you could rig up some 6 inch T fittings and share 2 of the big cloud line T6’s sucking air from inside of 3 tents?

I looked at this initially but ran into the issue of being able to control each tent's environment without electric dampers and controllers, making it just as expensive as 3 separately controlled fans.

Doing some more internet searching I found that ideally you want to circulate the air in your tent once per minute. This is all I'm really worried about, temp and humidity are not much of a worry. Now estimates of the reduction of flow due to carbon filters/scrubbers, is 20-25%. Assuming my original intention of a 4" fan and a 6" carbon filter to reduce intake suction pressure, I will assume 20% reduction (loss) and no loss in the pipe run after the fan since it will only travel a few inches directly out the tent without any bends. My tent is 151.875 ft³ * 1.20 * 1 minute = 182.25 cfm. Assuming my worst case, 151.875 * 1.25 = 189.84375 cfm. AC Infinity T4 is spec'd at 205 cfm but assuming efficiency loss of 5-15%, it ends up closer to 194.75-174.25 cfm.

I'm just not seeing a reason to go bigger other than for a few bucks more I can get twice the cfm fan for very little reason of needing a bigger one.

Are you worried about noise? I'm guessing that the smaller fan, spinning at a higher RPM, will make more of it.

I believe the 4" & 6" AC fans are 28 db and 32d, respectively. One will maxed at 28 db or possibly louder and the other will be less than 32db but at that level will it be a noticeable difference?

BtW, want to trade, lol?

109F and 45% rh today, are you sure?

I'd really just like to hear what everyone has for a setup, I feel ventilation gets skipped over somewhat until people start discussing VPD or run into issues with heat and/or humidity. Most just buy a big fan and call it a good day. Maybe instead i should ask what is the size of everyone's grow tent, size of their exhaust, how high of a speed does it run, and what are your environmental conditions? I have a feeling it will be a mixed bag of small fans running 100% and large fans running at 50%.

 

[The Phantom]

I did get the price difference wrong between the T4 and T6, it's $30 and not $40 like I previously stated. Overall the difference between (3) T4 or T6 fans, with tax, shipping, and 15% off comes to $81.18. Money that could go to carbon scrubbers, or seeds.

 

[013]

I wouldn’t go with electronic dampers. The left tent gets a 6 inch from 1 side of the T fitting, the right tent gets a 6 inch from 1 side of the other T fitting. The middle tent gets 2 different 6 inch ducts one from each of the other 2 T fittings but they could be reduced down to 4 inch intake to keep middle tent stable.

I’m running a 12 X 12 with 2 Mars SP 250’s plus 4 T5’s and a pair of 12 inch oscillating fans on low. It’s 90 outdoors today inside grow at canopy height it’s 83F & 58rh. During lights on the door can be opened and as the summer wears on I will switch fan speeds higher to move more air. May have to use dehuey but that brings more heat as you know.

I know there a lot of complex calculations to consider but I’d say supersize that biatch and it should pay dividends by running longer lifespan at lower speeds. But hey I’m an outsider & you know what you got to work with or against. Good luck man, keep us posted!

 

[The Phantom]

Might be worth buying one of each size and giving them a test, return the unwanted one, and buy the other two.

I'd like to run the tents connected together but they might not be all in the same room and will have different humidity requirements since some will be vegging while others flowering.

 

[TorturedSoul]

109F and 45% rh today, are you sure?

Wow, no. Walked over and mowed Mom's yard the other day, thought, "I hope I get the front done before I die." Looked at the thermometer on her (covered) front porch and it read 103F.

Starting to wonder, since we appear to be breaking records (or nearly so) each successive year, and the night time temperatures (at least in my area) are high enough now that everything still has a lot of heat from the day before, how food production is going to be affected in the next several years. There are different types of grains/etc. that they grow in Africa, but that's only going to work until we surpass the "comfort zone" for those.

Anyway, back to your thread, lol. I like your idea of running a separate fan for each tent. Seems like it leaves you more options. And if you "go large" and replace a tent (and its lighting) with something bigger in the future, you only have to upgrade that one instead of upgrading one really big and expensive one to an even bigger and more expensive one to keep all three adequately ventilated. 4" to a 6" is annoying, but not a huge expense. 8" to 10" might be.

 

[013]

Right I can see how that could create issues, like I said you know what you’ve got to work with and how it’s laid out. How much rework to get there, so yeah ignore my weak shizz!

 

[jamexican686]

Always up ur fan size so ur not running it on high constantly, thats always been a rule of thumb in the trades. I run 6" AC and it gets the job done in my tent exhaust wise. on the supply side I have a 4" vivosun which works ok meh. air exchange every minute with a lil negative pressure in the tent.

 

[oldsmokey]

If you have your heart set on the 4 inch. Just order one and try it out see if it's going to work for you before you order the other two. I already posted in your other thread so you know my advise. pH

 

[The Phantom]

Wow, no. Walked over and mowed Mom's yard the other day, thought, "I hope I get the front done before I die." Looked at the thermometer on her (covered) front porch and it read 103F.

Starting to wonder, since we appear to be breaking records (or nearly so) each successive year, and the night time temperatures (at least in my area) are high enough now that everything still has a lot of heat from the day before, how food production is going to be affected in the next several years. There are different types of grains/etc. that they grow in Africa, but that's only going to work until we surpass the "comfort zone" for those.

Come visit me and see what's grown in the desert on the US and Mexico sides of the border, you would be amazed at how much of the USA's produce is grown here in greenhouses, iceberg lettuce to name one. Grain, grasses, cotton, and pecans to name a few of the flood irrigated crops grown in fields. I work fairly close with state regulators when it comes to Colorado River water allocations and the facade of "everything is ok" is only going to last 5 years max before there will be a fight between the people that want to continue their residential oasis or water intense farming practices and what we can actually afford to provide. Direct reclaim to potable drinking water is and will happen here very soon and this time the public's complaints about the thought of drinking thier own waste will go unheard for the greater good.

 

[Apoc]

Never compromise on equipment, one autoflowering plant can net you 2200$ in flower easily.

Over a piece of equipment's lifetime you can harvest 10s of thousands of dollars of flower $80 is nothing in comparison.

One 4" fan craps out at 90% you lost your savings.

Grab your first set of seeds from new420seedguy and you'll save that $80 anyway and he has great seeds.

 

[The Phantom]

If you have your heart set on the 4 inch. Just order one and try it out see if it's going to work for you before you order the other two. I already posted in your other thread so you know my advise. pH

Thanks Smokey, I'm really not needing it to chase humidity or heat issues is the only reason why I think smaller may get me by. I do have a circulation fan on the inside of the tent to keep things moving and intend on keeping it in there and adding one or two to each of the three tents.

Always up ur fan size so ur not running it on high constantly, thats always been a rule of thumb in the trades. I run 6" AC and it gets the job done in my tent exhaust wise. on the supply side I have a 4" vivosun which works ok meh. air exchange every minute with a lil negative pressure in the tent.

That's very true but I'm also the type to say why but it of you aren't going to use it. What size tent do you run the 6" and 4" on? That was my next question of you found running the 6" too much for a passive intake and needed to switch to an active one. I know it wouldn't be an issue for me since I would run a 6" it wouldn't be at 100%.