inline vs duct fans

dank smoker420

dank smoker420

Well-Known Member
i am planning on getting a 4" fan for my 6" holes after i get a converter. from what i can tell inline fans just push alot more air then ducts. is that true? i am getting a small tent. 2'x1,5'x3' so a duct fan will do plenty good. are duct fans louder than inline fans? i want to have minimal noise.
 
Geronimo420

Geronimo420

Well-Known Member
A duct fan is actually a type of low performance inline fan. Noise level vary a lot, a value in DB is always indicated on manufacturer package. Duct fan normally emit less noise than a high velocity inline fan & for a small grow space they can do the same job at a lower cost. Using a high velocity inline fan will often require the use of a sound muffler and a variable speed controller.


Duct fan View attachment 2202833 High velocity inline fanIn-Line-Fan vortex.jpg
 
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CaliPhobia

Member
I have 2 435cfm fans for my 2x4x5(ft) tent. One venting the 600w hood and the other pushing fresh air into the tent from outside the garage. I live in Northern CA and the dead of summer has yet to hit but my recorded low is 64, high is 88 and it normally runs around 76-78 during the day. My plants have been thriving on that for over 5 weeks and I have had no issues with my temps, air, or plants. My fans when running full speed (which they always are) are not loud but they are not quiet. My 2 year old daughter constantly thinks the dryer is running in our garage (which is what I would compare it to as well) but she corrects herself and says "Oh, nope! Just daddy's garden!" I cannot offer any input on the duct fan being as I have not used them but I am considering a small one to push air in and use my 435 to pull hot air from the top instead of ushering air in..
 
*BUDS

*BUDS

Well-Known Member
If you have lengths of ducting you will need a centrif, if there is little ducting the vent fan should be ok. And the centrif is much louder than a vent fan.
 
dank smoker420

dank smoker420

Well-Known Member
alright thanks guys. i will deffenitly be going with a 4" duct fan. they are alot cheaper and i dont want something as loud as a dryer haha. i wont have any ducting but i will have a carbon filter attached to the fan. and be running a passive intake
 
skunkd0c

skunkd0c

Well-Known Member
i think the term "inline" or inline fan can be misused a bit
it is just about the shape of the blades, and what direction the air is pushed in
the ducting fits on each end of an inline fan so the input and output ducting are "inline with each other" 180 degrees

the fan i am using, is pre-mounted in a metal box to reduce noise, the ducting is attached at right angles 90 degrees , so my fan cant be an "inline fan"
the shape of the blades are pushing the air out at right angles to the input
an inline fan pushes the air to the center in a straight line
you can find diagrams to illustrate this if you want to search for them
the boxed fan i am using removes more air than a standard inline fan with less noise output :)
mainly due to the size of the fan and motor, the fan has a 6 inch outlet, but is using an 8 inch blade 250 watt motor inside the box

peace :)
 
Geronimo420

Geronimo420

Well-Known Member
dank smoker420 said:
alright thanks guys. i will deffenitly be going with a 4" duct fan. they are alot cheaper and i dont want something as loud as a dryer haha. i wont have any ducting but i will have a carbon filter attached to the fan. and be running a passive intake
Click to expand...
Unfortunately the use of a carbon filter require that you also use a high velocity fan.....but on the other hand it also cut some of the noise. A 4" high velocity fan couple to a carbon filter would run at a similar noise level than the advantage washroom fan or even more quiet if you go for a high-end one.
 
racerboy71

racerboy71

bud bootlegger
i started off with a duct booster, and yes, they're super quiet, but that's only because they're hardly doing any work ime.. mine was a hunk of junk, and in no way would i compare it tot he quality inline fan i have now..
yah, it's way noisier and i have to run it on a speed controller and a duct muffler to make it bearable, but the difference is night and day...
 
Ringsixty

Ringsixty

Well-Known Member
inline fan and controller
spend that extra money. you will be happier.
i did the cheap and ended upgrading. so, in reality, i spent more money and now have 2 duct fans sitting on a shelf.
:weed:
 
superstoner1

superstoner1

Well-Known Member
vortex fans are extremely quiet. but i still wrap mine in a bubble insulation blanket, mainly for keeping heat in fan not room, but also knocks out most noise.
 
BlueBalls

BlueBalls

Well-Known Member
I was using a duct fan in my veg tent with no ducting. It made a ton of noise.
It would also race as the airflow from the circulation fan would change the pressure at the duct fans intake.
Constantly fast, then slow, fast then slow. I was going insane from the noise.

I have an inline blower for my flower tent and it is hooked to a speed controller.
I noticed that the blower, when its speed was low, was much quieter than the duct fan.

So I bought another blower and connected it to a speed controller for my veg tent.
I am now living a better life due to reduced fan noise. YMMV.


 
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CaliPhobia

Member
Ringsixty said:
inline fan and controller
spend that extra money. you will be happier.
i did the cheap and ended upgrading. so, in reality, i spent more money and now have 2 duct fans sitting on a shelf.
:weed:
Click to expand...
What he said. You'll find yourself upgrading sooner or later..
 
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problemsolver

Active Member
A duct fan ( or duct booster) cannot overcome the static pressure load of any carbon filter. Furthermore, there are also some inline centrifugal fans that do not even do a good job of compensating for static pressure. I won't name those. I will tell you the preferred and second choice for a centrifugal inline fan. First.. can fan brand...second...vortex ( almost exactly the same but can fan has a much more contoured shape which permits better flow) . If you could find a centrifugal fan that has the same contours of the can fan that alone is not enough to say it is equivalent. Some fan manufacturers will use a 6" motor/impeller set in an 8" fan. It is quite permissible to use an 8" motor/impeller set in a 10" frame but not the aforementioned 6/8 switcharoo. Take these two variables ( contour/drive diameter) into consideration when choosing. Duct boosters are inefficient even on a stealth cab but sometimes necessary because of noise considerations.
 
Louisville79

Louisville79

Member
I have an 8 inch 440 CFM can fan with reducers connected 12 feet long of 6inch ducting with a carbon filter and 24 inch long round air cooled hood with 600 mh bulb.the carbon filter is at 1 end at the top of my 5x5x7 tent with the can fan attached to it then 5 feet of ducting running to my air cooled hood then about 7 more feet 6 inch ducting running out the other side of hood to outside the grow room!all in line with my air cooled hood and my room is still reaching above 90 degrees! should I keep the 440 can fan for my aircooled hood and carbon filter the way it is or should I just only use the can fan for the carbon filter alone and get a centrifigal inline duct for my hood alone and run two separate fans? I really need to get the temperature down and the one can fan connected to the carbon filter and my hood at the same time with about 12 to 16 feet of ducting running to outside is not reducing the heat and if it is I'd be afraid to see how hot it would be if I were not using one at all. I only have a 600 watt metal halide bulb in an air cooled hood but I don't think the fan connected to the carbon filter and the hood together with all that ducting is doing any cooling because I cannot keep my room below 92 degrees. I have another separate 440 cfm sucking air in from an air conditioned room and I'm still running temps above 90! can somebody please help with a suggestion on what I can do? I can't have a 92 + degree room anymore! it is causing a chain of events that are leading to unhealthy plants. Would having 44O cfm by itself on the carbon filter running outside and another 535 CFM in line centrifical high velocity fan running cool air only across the light bulb to outside,cool my room down? Meaning the carbon filter having its own fan and the air cooled hood having its own separate fan?
 
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