Do 'Soundproofed' Fans Get Hot?

Hi, everyone.

Just wondering what to do about soundproofing a fan. I see lots of people make boxes for them but does anyone ever have heating issues with a fan running 24/7, wrapped in a blanket and stuffed in a box?

This idea makes me a bit nervous, as in fire hazard nervous. Am I not understanding the mechanics of the fan? I also feel that the speed controller that I have (not a variac) is killing my motor. Is this just me anthropomorphising the whine and struggle that it seems to be under turned right down? I need to get a smaller fan in the hopes of lowering the 'stall' mark that it seems to need to be on but I am worried that the next size down is the exact same model with just a smaller opening.

Are 4" fans typically the same motor as a 6" fan? (mixed inline fan). And do they 'mind' being wrapped up and turned down to 0.1? Everything in my gut tells me that if my place ever burned down, it would be my 6" fan turned down to a slow crawl. Am I thinking stupid stuff?

..also, as a side note, if anyone knows where to get rockwool soundproofing bats from, please let me know. I saw some on ebay but I'm hoping that that wasn't a typical price. Know what price is not too much for one pack?

Thanks, everyone.

They do run hot but are designed to withstand the heat
As far as a speed controller if it came with the fan, but not all inline fans are designed for varying speed
EDIT: I never slow down my fans these days

i have mine in a plywood box filled with rockwell insulation,not tightly packed.works well.nice and quite.

A fan has a motor which is normally directly attached to the fan blades, in effect they are self cooling.

That said I wouldn't want to pack it in anything flammable.

My old one was an 8" Isomax/airforce 2 silent fan, it wasn't silent at all but built into a silencer which is just a tube with acoustic foam, which I don't think is flame retardant.
Because it was still noisy I had a new fridge freezer so I used the box, which was huge, filled it with acoustic insulation (high density rockwool) which is flame retardant.
I also did the same with my veg tent fan.
It did help but took up a lot of space.

For rockwool slabs use a builders merchant. Its not cheap. I bought enough to insulate the whole floor of the house, walls and ceilings.
https://www.condell-ltd.com/rockwoo...MItNWaup7i5AIVQ5nVCh2LNwkWEAYYBSABEgJu7_D_BwE

In all honesty I think your far better buying a bigger fan that is already low volume and using a voltage stepper /variac to slow it down.
I use squirrel cage box fans these days, they are less noisy than my circulation fans.
There are low volume fans available but you need to be careful and look for the db rating and know at what distance it was measured.
Some of the so called silent fans like the airforce2 I had are actually rated at 50db which is not even close to been quiet.

Ones I have now are 23db. They are nothing fancy , Chinese no name , but possibly one of my favourite purchases.


If your place ever burns down it will be a plug not plugged properly in or a male/female connection not fully plugged in or a light not hung with something secure and falling directly onto something. It wont be your fan.

It doesnt hurt them. I've wrapped mine in moving blankets and put them in styrofoam lined boxes an left em for over a year.

Cheap speed controllers can damage some fans but I've ran quality speed controllers for years without any issue. The cheap one caused damage pretty quickly

Wow, thanks, guys. This is the fan that has so far made the cut, to replace the 6" one that I just bought. Just not sure how low it can be turned down as it reckons it does 322 cubic metres/hr. (190 cfm). I have a tent that has 7 cubic foot volume. Seven. Thanks, coreywebster for your thoughts, I appreciate it a lot.



Here's the 6" one that I already have: Chinese as well. (even has backward letters stamped into it, haha).



Here's the 4" version of it. Is this the same motor as the 6", do you think?


Specifications


Model Voltage/Frequency RPM Capcitance CFM Deibel
100MM (4" Inch) 240/50 2350 1.2UF 180 35
150MM (6" Inch) 240/50 2350 1.5UF 375 37
200MM (8" Inch) 240/50 2300 4UF 730 40





After reading your post, Corey, I think that I'll go and find some low volume fans to consider.

coreywebster said:

A fan has a motor which is normally directly attached to the fan blades, in effect they are self cooling.

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Awesome, I was hoping the answer might have been something like that.

coreywebster said:

My old one .................filled it with acoustic insulation (high density rockwool) which is flame retardant.

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Yeah, I saw while searching that someone posted in another thread a video of a rockwool soundproof box putting an alarm into it and you couldn't hear it. Looked up that product and went price shopping. Seems that 50 Hertz is a difficult pitch to hide.

coreywebster said:

For rockwool slabs use a builders merchant. Its not cheap. I bought enough to insulate the whole floor of the house, walls and ceilings.
https://www.condell-ltd.com/rockwoo...MItNWaup7i5AIVQ5nVCh2LNwkWEAYYBSABEgJu7_D_BwE

Click to expand...

https://www.condell-ltd.com/rockwoo...MItNWaup7i5AIVQ5nVCh2LNwkWEAYYBSABEgJu7_D_BwE

The reviews for that show a few happy soundproof customers, so I think I'll do that.

coreywebster said:

In all honesty I think your far better buying a bigger fan that is already low volume and using a voltage stepper /variac to slow it down.

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Yeah, that was the idea behind buying the 6" fan. I read everywhere to oversize the fan so that it could quieten with a speed controller, then oversize the ducting and filters etc, but nowhere did I read a LOW VOLUME large fan. The tiny 200 cfm fans that I'm looking at are to move 7 cubic feet of air, through 100mm filters. So still needs to be set at 1/20 speed. I think that 'low volume' will be a definite step in the right direction for me. Thanks a lot for mentioning it.

coreywebster said:

......... look for the db rating and know at what distance it was measured. ....Some of the so called silent fans like the airforce2 I had are actually rated at 50db which is not even close to been quiet.

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I noticed that, as well. For a few hundred bucks, 50 Db is ridiculous.

coreywebster said:

Ones I have now are 23db. They are nothing fancy , Chinese no name , but possibly one of my favourite purchases.

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Good to know. I've wondered whether a spinning rotor was too complicated for a knockoff brand to replicate for half of the price.

coreywebster said:

If your place ever burns down it will be a plug not plugged properly in or a male/female connection not fully plugged in or a light not hung with something secure and falling directly onto something. It wont be your fan.

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Also good to know, as I am very diligent with connections, stoves, toasters, candles, etc. It only takes one house burn down to be on that sort of thing, like soup on a slipper. 35 years later, I can still smell it.

Thanks everyone for your replies. You've been very helpful and I appreciate it.

the issue isnt always the fan itself but the echo through the ducting. Flexible plastic duct is the cheapest and sound attenuation duct is the best

the way i realized this is i used hard duct at first. the echo through the metal is what does it!

you can also use metal duct with acoustical liner instead of that expensive sound attenuation stuff

growingforfun said:

It doesnt hurt them. I've wrapped mine in moving blankets and put them in styrofoam lined boxes an left em for over a year.

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Thanks, growingforfun. I was going to reply in my previous post but it got to 1am and I needed to go sleepies.
I have a bunch of furniture wraps here, I'll have a play around with your suggestion before I order the rockwool.

growingforfun said:

Cheap speed controllers can damage some fans but I've ran quality speed controllers for years without any issue. The cheap one caused damage pretty quickly

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Would this be considered a cheap speed controller? It is the only controller (in that shop) that didn't have specs to run a larger drawing fan and it seemed like a waste to buy expensive ones just because they could handle a billion more amps/watts etc.

My fan specs are:

Model Voltage/Frequency RPM Capcitance CFM Deibel Watts Amps
150MM (6" Inch) 240/50Hz 2350 1.5UF 375 37 52 0.21?

myke said:

i have mine in a plywood box filled with rockwell insulation,not tightly packed.works well.nice and quite.

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Thanks, myke. I'll be making up a box for it today and if I can't get rid of the noise, I'll definitely get some rockwool for soundproofing. I've seen that work in a video and if it can shut 50Hz up, I'll be a very happy camper.

Herb & Suds said:

...As far as a speed controller if it came with the fan, but not all inline fans are designed for varying speed...

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I think that I'll try the 4" Vivosun with the built-in controller and see how that one goes. I've seen a few posts here that like the sound level of them and I'm not sure what to look at when trying to pair controllers and fans. I tend to research the crap out of things and pairing a fan to a controller is just one more thing that I'll own that I became an expert on, before ever holding it. For a single purpose item, I'm better off just taking someones word that it will do what I need and save reading White Papers for information that I'll use more often. I feel like by the time I've lost my marbles, I'll forget how to tie my shoes because learning the difference between a Swiss clocks hands and a German clocks hands took its place. Not really sure if that's how the brain works, but I do try to learn only useful (to me) stuff, just in case. Maybe I'll look it up.

Nizza said:

the issue isnt always the fan itself but the echo through the ducting. Flexible plastic duct is the cheapest and sound attenuation duct is the best

Click to expand...

Thanks, Nizza. The original plan was a 4" fan with 6" acoustic-dampening ducting. Then I crazily upgraded the fan-size but it is still silent coming out of the ducting, just because of how extremely low I need to run the fan for my tiny 7 cubic foot tent. My problem at the moment is the Hz coming from the motor itself.

Nizza said:

....the way i realized this is i used hard duct at first. the echo through the metal is what does it!

Click to expand...

I was playing with the idea of using PVC pipe as ducting. Still not completely off the cards yet, as I'm still waiting for stuff to arrive so that I can put it all together and experiment with different materials/placing. At the moment, I'm testing things with no light(has inbuilt fan), no tent, and no filters. So my findings could well change upon their arrival, so I am researching now how to quieten the fan not even hooked to anything in the hopes that once it is all hooked together, I'll have no complaints.

Thank you all for your input. It is very helpful to me and I appreciate you taking the time to respond.

I just bought an AC Infinity fan with their temp/humidity controller; So far impressed. I had the HyperFan before that and even purchased it's 'smart' controller but it doesn't do humidity based. Definitely check out AC Infinity if you've not bought one yet.

Myself I've been considering a box as well, same hesitations. I considered using 2 differing materials to try and capture multiple frequencies. Also considered car audio stuff like Dynamat or other easily sourced sound dampening materials if I knew they were fire proof/retardant.

NewGrower2011 said:

I just bought an AC Infinity fan with their temp/humidity controller; So far impressed.

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Hi, NewGrower2011. I'm happy to hear that you are impressed with the AC Infinity. ...For your sake, as well as mine, as I bought one the other day. Should be here on Monday, so I'll have to sort out a decent adaptor for it to run in my country. From what I can tell, it is dual-voltage and shouldn't need a step-up voltage converter. I'll wait until it gets here, to be sure.

Like you, I bought the T series. Mine is the 4" (T4). I didn't really have a problem with the S series, except that I didn't like how the switch worked. Can't remember the exact problem but I think you had to turn it all the way up to turn it off, or something. That rings a bell. Click, click, click, click, click, to cycle back to 'off', and if you missed 'off', then you'd need to click through the eight speeds again, to get to it. Not the most stealthy 'quick, turn it off' switch.

I didn't particularly want the screen and all the bells and whistles. (The alarm, I'll be looking to disable). But for how much I had to pay to get the cheaper one, (with a switch that I felt could be a potential problem for me), I justified just spending the extra to be able to turn it either up OR down in one click. As well as looking at what the temperature and humidity gauges would cost, because they might just come in handy, trying to replicate some of the nice grows documented, here.

I'm currently juggling Uncle Bens and RM3s threads and would like to replicate some of their fine work, so the closer I can get to their conditions, the better. Sidetrack question, Is riddleme and RM3 the same person?

NewGrower2011 said:

.....I've been considering a box as well, same hesitations. I considered using 2 differing materials to try and capture multiple frequencies. Also considered car audio stuff like Dynamat or other easily sourced sound dampening materials if I knew they were fire proof/retardant.

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Yeah, I looked into all that stuff too, but have decided to stop buying stuff until all of the gear I've already bought is in the same place. (Still waiting on the tent, light and filters, they were backordered).

Now that you have your AC Infinity, do you feel that it needs to be quieter? I plan to be running mine at hopefully less than 1/4 speed (7cfm + 2x 4" Phresh filters) so I hope that noise will not be a problem.

I did end up using a strip of furniture wrap around the noisy fan that I have and chucked it in a box just to see if it was worth doing properly that way. It did muffle it, but only having done a quick and dirty 'proof of concept' with it, I can't say how well I could've got it to work, with what I was using. (and in that space).

Glad to see that you have bought something that you are happy with.

Shoulda got a Panasonic whisper. Comes with its own box. Those radiator cooling fans ain't powerful enough to push through a small humid carbon block.