New Grower Intake fan or Passive inlet ?

[true]

Do I need a fan pulling air into my room or is a few 6" holes enough?


At the moment Im running a 12" inlet fan (low power) and a 12" outlet fan (high power).
All is well except for the noise of both fans.
I know we got a bit of heat the moment but fan noise is my biggest problem with or without much heat.


Im tackling one fan at a time.
I got thinking do I really need an intake fan.
Why not have say 4 x 6" holes with bug shields on and let the outlet fan suck as much as is needed out.


Another reason I got thinking about this is my room is whistling like a bastard.
I know I need some neg pressure but I think my room needs more air than the fan going in can provide.
Inside my room air is being pulled from every possible tiny space.
I have air whistling past my skirting boards.


So all this got me thinking I need more air in and why not dump the fan and make more passive intakes.


Anyone of you lovely clever growers got a thought on this?

 

[namvet25]

Try it with out the intake fan and see if your getting fresh air coming in.Hold a lighter by the intake hole and you should able to see air movement.

 

[Bilbo]

Try a variac type fan controller to turn it down a bit with no hum and the general rule of thumb is to have at least twice the size passive intakes as your exhaust fan, your 12" is about 113"sq so you'd need 230"sq of passive venting.

 

[jamestiger]

1st find what is causing the noise and where adsactly it is coming from , is it from the fan itself or from vibration where it is toutching something ?. you can use a carbon filter on the outlet hole this will muffle the noise from theducting ,also insulate the ducting , build a muffle box for your fan that will stop a lot of noise , susspend it on a cord to stop it from vibrating if it is touching something , use passives for your intake but have them the opposit end away from the outlet so the fresh air will pass over the plants not be sucked directly up the outtake if the holes are close to outlet , hope this helps a little

 

[wwwillie]

Like Nam said try it and see. The rest of the advice is also good for sizing and cutting down on the noise. But moving air about causes noise so it won't all go away. I am not a fan of active intake (pun intended). They may need to be used but not in every instance. My issue is that with an active intake, if the exhaust fails you will have positive pressure and that's not good for odor reason at the very least.
Experiment carefully and I am sure you will come up with the solution.

 

[true]

Hello everyone!


Thanks for all the replies.
Years ago when I grew I just had a passive intake.
In fact Ive never had an active (fan) intake, so not sure where Ive picked this up from but this time round Ive got a fan blowing in.
I just thought it was better but now I come to think about it, passive would be fine, perhaps a few more holes than 1 x 12' hole I use on my intake fan.


Anyways Ive sussed the problem.
When I set my room up everything was great.
Active in , massive out and no heat problemo's
Now we are in summer, my lights are turned right down and heat can get up in the 30's.
No doubt we are all in the same boat here.


Here's the thing yesterday while checking the bug guard I fitted to my 12" intake it was totally and I mean proper clogged up.
The air flow was almost nothing. I was checking the outside of my room thinking something was dead in there and blocking the duct.
I could not believe what I saw, it was like ten hoovers had been emptied and my intake had sucked the lot in.
Hey those bug guards do the job alright.
Its been 3 months or so and its totally blocked.
Im going to buy another spare guard and swap them out once a month from now on.


Because my intake was blocked my outlet fan was drawing air from where ever it could.
Thats why we had the skirting board drafts and the squealing of air rushing past my doors.
I still think my room could do with more air in than its getting.
Im going to cut a couple of 6" holes in the side wall, screw on wall flanges or spigots... not sure what you call them and then fix a couple of bug guard filters over the inlets.
If this is too much air I can easily block one hole up or open more.


Im planning on adding a couple of LED lights when Dutch Passion release there new models later this year. Im thinking this will help knock down my temps. Also Im going to try a portable air con machine to see if this can make a difference.
Inside the room there's a fair bit of noise but my room is all insulated and inner room noise is not the problem.
Its more a problem with air wooshing in and out of the 2 fans outside the room Im struggling with.


If you have tights or filters or bug guards fitted over your intakes go and check if there clean.
Potting up my new Dutch Passion beauties this weekend..
Thanks again everyone for the rapid replies!!


True.

 

[letmeread]

I'm in the proccess of setting up my grow space and I'm using a 30cm fan for ventilation out, its got 280mh3 capacity max, at which rate its making alot of noise. I turn it down to about 200mh3, at this rate it's quiet, and for intake I've drilled a 15cm hole and fitted a computer fan on it, turned it down to about 1000 rpm and about 8 out of 12 in voltage.

This way it's all very quiet, I like having the intake there, it feels fresh although it may not be nesecarry.
this is a 2m x 1.2m x 60cm wardrobe (hight x width x depth).