# Help........most effective way to reduce noise from exhaust fans??????



## aotearoa420 (Dec 26, 2010)

Hello everyone, I have a veg and flower room in 2 separate areas. I have a 150mm inline fan exhausting both cabinets (veg room 3.5 x 2ft and flower room 2.5 x 4.5ft) both about 7ft high. now the fan is real loud, can here it a bit through my floors and i am wanting to reduce this as much as possible. have tried a homemade approach by adding insulation to the ducting and have lined my floor with insulation but can still the fan anyone got any ideas??? make a box and cover exhaust fan perhaps??? have seen the bungy style, but seems all the noise is from the "air in" of the fan not the "air out"???????????? someone help as I have a lot of people who stop by and dont want the noise to give me away.....................


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## devero420 (Dec 26, 2010)

I have noticed that Money = Silence when it comes to fans. The more money the fan cost the quieter it is. If it is mounted to something hard like a floor Joyce, it might transfer vibrations, so you may try to avoid bolting it (or its chains) directly into wood, instead put a piece of rubber through it kinda like a tranny or engine mount. Also you can build inline mufflers so you wont be able to hear the fan through the duct.

http://www.gardenscure.com/420/do-yourself-projects/138045-diy-inline-fan-muffler.html


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## Pullin' weeds (Dec 26, 2010)

If you can put in a speed control, most fans run super quiet at about %75, and nearly silent at %50.
I find it's always best to put in a bigger fan than you need and then dial it back.


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## Pross (Dec 26, 2010)

I have the opposite problem. The only sound I have is coming from the air rushing out of the flexible ducting. I have a 4" centrifugal fan mounted mounted to the boxes ceiling. No vibration just the whoooooooooooossssh constantly coming out of the ducting. I ordered a fan controller off e*a*. Hope this will help.


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## NLXSK1 (Dec 26, 2010)

There are many things you can do.

1. get a speed controller to slow down the fan. This is really effective.

2. get a muffler for the intake or output. This will probably cause some resistance in your ventilation so I wouldnt use it for grows that are having trouble with temperature.

3. box the outside of the fan (this will only be effective if the fan housing is making noise for some reason.

4. Buy a more expensive fan and speed control it.

Also, it might not just be the sound but the vibration. Sometimes by hanging the fan by bunge cords or some other method prevents the vibration from travelling to the building structural members.


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## hammer6913 (Dec 26, 2010)

Pross said:


> I have the opposite problem. The only sound I have is coming from the air rushing out of the flexible ducting. I have a 4" centrifugal fan mounted mounted to the boxes ceiling. No vibration just the whoooooooooooossssh constantly coming out of the ducting. I ordered a fan controller off e*a*. Hope this will help.


 
be careful with a rheostat i tried that with the fan on my wood stove and it started to overheat. dont know if it was the rheostat or what but i took it off and the fan runs at the right temp now. hope this helps


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## aotearoa420 (Dec 26, 2010)

Thanks guys
Its not so much the fan thats making the noise as it is brand new its the "whooshing" sound thats the problem
have it in my basement so can hear the fan at night times and outside just.... so will the boxed up technique with bungys only
work if the fan itself is rattling against a structure??? I want to box in the whole unit line it with acoustic material and hope that works


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## aotearoa420 (Dec 26, 2010)

Pross said:


> I have the opposite problem. The only sound I have is coming from the air rushing out of the flexible ducting. I have a 4" centrifugal fan mounted mounted to the boxes ceiling. No vibration just the whoooooooooooossssh constantly coming out of the ducting. I ordered a fan controller off e*a*. Hope this will help.


Thanks guys
Its not so much the fan thats making the noise as it is brand new its the "whooshing" sound thats the problem
have it in my basement so can hear the fan at night times and outside just.... so will the boxed up technique with bungys only work if the fan itself is rattling against a structure??? I have a centra fugal 2 speed so its on the lowest setting now I want to box in the whole unit line it with acoustic material and hope that works


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## zem (Dec 26, 2010)

if it's only the "whoosh" sound, you could just get a bigger duct


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## 420forme (Dec 26, 2010)

whoosh sound, or air movement can be silenced by use of a muffler, and insulated ductwork. Boxing in the fan doesnt help too much.


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## aotearoa420 (Dec 26, 2010)

420forme said:


> whoosh sound, or air movement can be silenced by use of a muffler, and insulated ductwork. Boxing in the fan doesnt help too much.


not what i wanted to hear man

have just got me all the things i needed to make box but will carry on now and hopefully it will reduce noise a bit
insulated ducting must be next on the "to get list"....


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## aotearoa420 (Dec 26, 2010)

aotearoa420 said:


> not what i wanted to hear man
> 
> have just got me all the things i needed to make box but will carry on now and hopefully it will reduce noise a bit
> insulated ducting must be next on the "to get list"....


Well it works have finished building box. Lined it with an old foam mattress so its about 2inch thick after it was compressed and stapled to inside of box. had a 2way air inflow so covered the junction as well very happy, sounds like a glider now in comparison to a jet.


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