Duct fans

I was wondering if anyone has used duct fans to power their exhaust. I am hoping to get one to put inbetween my growspace and my carbon filter. Does anyone have any tips or suggestions?

Duct Diameter:.................... 4"
Unit Weight:....................... 2.50 Lbs.
Max Boosted CFM:............. 80
Free Air CFM:..................... 65
Amps:................................ 0.30
Housing Length:.................. 6"
dBA:.................................. 52
Blade Type:........................ Polycarbonate
Motor: 110 V, Class B, Thermally Protected (T.P.)

They howl like a sonofabitch, through walls.....unless you get them positioned just right...I would reccomend something with a little more umff for a carbonscrubber. Those nice centrifugal fans are way more expensive but you'll know where the money went. Peace Heres a good one EcoPlus 4" Centrifugal Fan 170 cfm | Exhaust Fans & Circulators

I was thinking about using that same exact one Dr. but i figured for my situation i am going to need a 6" because the carbon scrubber is going to reduce my cfms and if im only working with 80 to start with i figure there wont be much left after filtering. The 6" i believe moves about 180 cfm anf the 8" about 250 cfm if i am correct. I would however use the 4" for my intake. I would go with the bigger one for exhaust, if it gets to the point where it over cools for you, you can always put a rheostat inline and control your fan speed with it. Hope this helps.

Blaze is the howl coming from the motor or the fan blades,can you tell?

Even though the cheap inline fans are rated at those cfm's they will not push as hard through ducts as Centrifugal fans rated at the same cfm's will. Centrifugal fans barely loose any cfm's when venting through ducting while doing it with much less noise. I will never have another friend go"do you hear that howling". The "your just high" remark wasn't cutting it anymore. Peace

its the fan blade

Crispi tried this too ,
W/ a 6in. h/p 240 cfm inductor from home depot on a 6in. dia 18in long scrubber and it didn't do a damn thing . House was A.F.U. -n- stinkin . Save your money for a Vortex , Hurricane blower .
Peace
Crispi :jointsmile:

Thank you very much for all the responces and thank you BlazeIdo for finding the link for the fan. I am on a tight budget and was wondering if you had any $100 suggestions that only costs $20 or so lol. I have about $80 more I can put into this grow and that is going towards $40 in lights, and $40 in venting. The Lowryder strain doesn't smell much and now that I think of it, I won't be needing a carbon scrubber since I have my ionizer running, a grow room full of herbs below it, and a can of ozium incase smoking bud stinks up my room.

So how about an exhaust fan that doesn't have to push through a carbon filter? I have about 11.2 cubic feet of growspace and I am trying to change the air every 20 seconds or so, so how about an 60cfm computer fan?

I am thinking about getting this one, it pushes between 55-90 CFM depending on how hot it is. Is 40 dB(a) too loud?
Vantec Thermalflow 120mm Double Ball Bearing Fan TF12025 at TigerDirect.com

Whats up Dr. hashman, was just going through the post and thought ah shit, I've just gotta put in my 2 cents. There's not one of us on here who has not tried a computer fan, and some have luck with that method but if you wanna take this grow up a notch buy a fan's fan. One of those bad mofo's made for people like us. Good fans are reliable, quiet and they get results if applied properly. How big is this space? Closet or something. See you know some about airflow. For my 5x2x8 closet I have 2 exhaust fans, one when the 400 watter comes on and one for smell, exhausts 24/7 through a carbon filter. Lowryder low smell maybe but thats not no smell, pot plants are smelly, it's not like a shit, after you flush you spray and your done. Not with plants. Heres some pics of the fans similar to what I use. They are around 100 dollars a piece but worth it. Good luck let me know if i can help. May need to cut holes in drywall and hang if possible with bunjy cords to reduce unwanted vibration.

Those duct fans are useful only when helping a main fan do its job - If you have a long run of ducting or a couple of turns they can help keep up the velocity. Unfortunately the computer fan you posted will do even less unless you keep it completely unrestricted, eliminating any filtering you can do... The squirrel cage fans like mulletman posted are the best bang for the buck, although not the quietest. Anyplace by you do HVAC salvage for old heater fans?? Restaurant supply salvage, the fans from industrial range hoods are good too. I got a 1400 odd cfm blower like that (only its 240V) for free from a place by me

Cheap, powerful, and quiet are three words in the fan industry that don't add up - Pick two or shell out $$$

Here's another "me too"... I got a 250cfm duct fan for an outtake and it barely worked when it met resistance (scrubber). I got a 7" Vortex and used the inline fan as an intake and now everything's great.

There are 11.4 cubic feet in my grow room. So if I put an exhaust fan with a carbon scrubber on it, and assuming that it only get 30% efficiency when it has a filter, I would still only need a 120 cfm fan. Is there any possibility that I could buy a small squirrel cage fan (or some equivalent) that put out 150 CFM and costs under $70?

At the local shop they sell three different sized squirrels. Small like 100 cfm, medium like 165cfm, and twice the size of medium 400 cfm. Ive got all three but only use the small for my scrubber and the medium for my 400 watt air cooled. Keeps temps nice and allows me to drop the light close. The price for them is like 80 for the small, 100 for med. and 110 for the large. These fans are a little loud with vibration and turbulence being my biggest concern. All and all they are working great, but I really don't have much experience with any other fans. Good Luck.

Technically my grow is a stealth grow so I will check some of those out and see what fans they use. Just cuz there is some drywall and paint between the grow and my room doesn't mean I don't have to worry about sound.

say cuz, your not alone. Theres probably not one among us that doesn't got to worry about sound, smell, light.

if you need low vibration i suggest a vortex fan

Quote:

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Originally Posted by Dr.Hashman

Technically my grow is a stealth grow so I will check some of those out and see what fans they use. Just cuz there is some drywall and paint between the grow and my room doesn't mean I don't have to worry about sound.

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I'm in your boat, I only have a wall between other mates so I must keep it to a minimum, I'm just glad you can't hear the ballast from my hps, but now I must think of a pretty slick way to get the ventilation going without making noise.

I was actually planning on drilling through the wall, and housing the fan and scrubber *outside* the closet inside a little speaker box, and then running tubing back through the wall into the closet right up to the light to remove the heat. Hope something like that will be possible though.

Edit: Isn't there types of sound proof dry wall you can buy?

If you absolutely need the quietest fan that can move some good amounts of air, the only solution I have found is the Panasonic Whisperline. Not the most powerful, or best bang for the buck, but the quietest I've ever heard. About ~ 60 decibels

Panasonic FV-30NLF1 WhisperLine™ 340 CFM In-Line Fan (1.7 sones) [FV-30NLF1] - $160.00

^I use that one to suck from the scrubber, and then blow through the cooltube. The loudest part of it is the actual air moving. The fan is virtually silent in the room.

They make a less powerful, cheaper, quieter 4" version and then for a few bucks more theres an 8" 440cfm, which I plan on using in my next room

I saw a DIY scrubber over at IC that uses the Panasonic WhisperLine fans.
International Cannagraphic Magazine Forums - Panasonic Whisper Fan Carbon Scrubber Tutorial: Quietest most efficient fan ever!

I think I might invest in one and make a scrubber/exhaust with it like that guy did. I'm building my own desk right now so I can learn to build furnature type things, then I am going to build a cabinet for my grow and I will probably measure out a completed carbon scrubber and build a little section just for that.