Conflicting advice everywhere on intake/exhaust for SMALL tent...

I'm purchasing a small tent, 20 x 20" at the smallest or perhaps up to 20" x 36" x 60"...
Guy at the hydro store basically said "You need an exhaust fan, dont need an intake fan if it's that small"

Is he right? Best place for sourcing out a fan(s) for a small grow tent with 1-3 plants?

It sort of depends. What kind of light are you going to use? If the exhaust fan is large enough it will create negative pressure and suck room air into the tent and that may be enough. 20 x 20 is pretty small so a fan that is "large enough" will still be pretty small.

I just ordered the tent. It's 20 deep by 36 wide by 63 tall. I plan on using a couple LED UFO's 135ws probably or a 240w LED with heavier reds and supplement early on with some CFLs maybe for early veg stuff.

So, not a lot of heat, and the light has it's own fan and heatsink in it.

This calculator is cool for those that don't have one: http://cheaphydroponics.com/Merchant2/cfmcalc.htm

That says I only need about 5 CFM to move air every 5 minutes and 25 CFM for every 1 minute.

Is this overkill?

http://www.amazon.com/Ideal-Air-Inline-Duct-Booster-70CFM/dp/B00023TF74/ref=sr_1_8?s=lawn-garden&ie=UTF8&qid=1362734476&sr=1-8&keywords=exhaust+inline+fan

Don't know if seeds matter btu just ordered fem Snow White nirvana seeds and some Bubblelicious seeds as well. Gonna start with the Bubblelicious ones to learn how to sex plants and save the Snow White for go #2.

I don't know what your situation is but, I will give you a heads up. I have grown bubbleicious and it stinks...a lot. Remember that the light with it's heat sink and fan are going to be inside the tent, that fan is just to keep the lamp cool and dump the heat inside the tent. If you want to try that booster fan alone, I say do it without your plants in it. Run the lamps for a few 18/6 cycles and see what the temps are like in there. If it works, that's cool. If not you can get a larger exhaust fan and use the booster as an active intake. Once you have control of the temps in the tent go ahead and germ the seeds. Ounce of prevention...Good luck!

ow.douglas said:

I don't know what your situation is but, I will give you a heads up. I have grown bubbleicious and it stinks...a lot. Remember that the light with it's heat sink and fan are going to be inside the tent, that fan is just to keep the lamp cool and dump the heat inside the tent. If you want to try that booster fan alone, I say do it without your plants in it. Run the lamps for a few 18/6 cycles and see what the temps are like in there. If it works, that's cool. If not you can get a larger exhaust fan and use the booster as an active intake. Once you have control of the temps in the tent go ahead and germ the seeds. Ounce of prevention...Good luck!

Click to expand...

Awesome that was some of the most sound and practical advice anybody has given me thus far ow appreciate it. What are good temps? 65-75?

That room is dedicated to this so the smell isn't too much of a concern but I'm going to try to keep it out of the rest of the house, if I can contain it to that room, that's cool and my fiance won't bitch. I'm going to run it through an inline filter and use some other smell elimination stuff in hopes to keep it not as bad.

A good 5" fan and filter setup on a speed controller would be perfect for creating enough negative pressure to not worry about powered intakes.

Don't punk out on a filter setup otherwise her indoors will be right in your ear about how she can smell it walking up to the house outside.



J

36OhBuds said:

I'm purchasing a small tent, 20 x 20" at the smallest or perhaps up to 20" x 36" x 60"...
Guy at the hydro store basically said "You need an exhaust fan, dont need an intake fan if it's that small"

Is he right? Best place for sourcing out a fan(s) for a small grow tent with 1-3 plants?

Click to expand...

He is probably correct; you don't need an intake fan. My tent is 5 x 3 x 7 and I just have one passive intake open about the size of a girl's softball and everything works fine. Negative pressure with a complete 4" exhaust system.... zero odor outside the tent.

jondamon said:

A good 5" fan and filter setup on a speed controller would be perfect for creating enough negative pressure to not worry about powered intakes.

Don't punk out on a filter setup otherwise her indoors will be right in your ear about how she can smell it walking up to the house outside.



J

Click to expand...

Word -- so what price range am I looking at for a decent filter and fan and how often do you have to replace them? So I assume they're all going to be 4". For inside the tent and ambient airflow I just need a desk fan or something on low right?

I looked all over the forums after reading your post but can't find specifics, the search is so cluttered with people saying "go search" that it's worthless sometimes... amazon link me (hopefully prime)?

Malevolence said:

He is probably correct; you don't need an intake fan. My tent is 5 x 3 x 7 and I just have one passive intake open about the size of a girl's softball and everything works fine. Negative pressure with a complete 4" exhaust system.... zero odor outside the tent.

Click to expand...

What are you using? Mind pointing me at your setup just so I have an idea? I'm about a third your size as far as CFM at 3 x 1.7 x 5 so if I get what you have I should be good to go. haha

I'm sayin your hydro guy is right, you don't need an active intake fan (assuming you have negative pressure which is created by a proper exhaust system).

Here is my setup, on one hand I want to change it up at the end of my current grow to reduce the amount of duct and bends... If I put the silencer outside the tent, I could get away with a lot less bends. On the other hand the shit is working perfectly and "if it ain't broke, don't fix it" comes to mind. The light usually hangs down a couple feet lower than in the photo because the ceiling is 7' high. Hence the need for all that duct on both sides of the cooltube.

Wow yeah that helps a lot thanks. That picture gives me some ideas how I can make mine fit in my small tent... time to go mcgyver

What do you think is like an expected price range for that setup? $200?

More like 40 carbon filter, 60 cooltube, 75 inline fan, silencer was like 60 or 70 from hydro store... plus about 30 or 40 bucks in misc shit... duct, 6" to 4" reducers, clamps, bungee cords to hang fan. 20 bucks for the light hangers. Plus shipping.

So $325 or less depending how much shopping around and diy you wanna do.