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Exhaust fans for network closet

Linwood

Active Member
Setting up a new house and chose a coat closet to become my network closet.  Right now it only gets up to about 80, but it is less than half populated.
 
I thought it would be easy to find a through wall ventilation fan.  I can exhaust to the side of the closet into a utility space.
 
I thought I could just buy something, cut a whole in each side, and shove it in.
 
I am struggling to find such a thing, well, with a couple of caveats.
 
 
https://www.amazon.com/Broan-512-Utility-6-Inch-Plastic/dp/B001501LHK/ref=sr_1_1?keywords=B001501LHK&qid=1553008706&s=gateway&sr=8-1
 
(Broan 512 Room to Room Utility fan in case the link doesn't work). 
 
something like this looks just fine, but it says 3.5 Sones which is about 45 dba I think, which is really loud.  I do not want to hear it if I'm more than 5' or so away.
 
Infinity makes a bunch of "room and closet" fans, e.g. 
 
https://www.amazon.com/AC-Infinity-High-Airflow-Equipment-Enclosures/dp/B0788ZMZ7X/ref=sr_1_1?keywords=B0788ZMZ7X&qid=1553008889&s=gateway&sr=8-1
 
But they are thin.  Looks like I would need to frame up around it, essentially making a duct.   They show it mounted in a door (at 2.28" it's a bit thick for a door though or I might consider it).   Unless I'm misunderstanding -- it really otherwise looks good.
 
These look like a nice cheap way -- could just control with a smart plug -- but same issue, I would need to build my own duct.
 
https://www.amazon.com/AC-Infinity-Cooling-Ventilation-Projects/dp/B009OWVUJ0/ref=sr_1_1?keywords=B009OWVUJ0&qid=1553009031&s=gateway&sr=8-1
 
It's not that I cannot build my own duct, I can probably manage it, but I have enough DIY tasks right now that it is not high on my interest list.
 
I would really like to find something already made to just sit in a standard 4" wall, ready to go.
 
Anyone know of such a thing, or should I break out the sheetrock and mud or sheet metal?
 
Thanks,
 
Linwood
 

neillt

Active Member
I have a panasonic that vents outside through the side wall.  Let me see if I can find a model number for you.
 

Linwood

Active Member
I don't have an outside wall, but if it fits....
 
After writing this I realized I have another question... maybe I don't need a duct.  If I go into the wall on one side, and just put a grate on the other.... 
 
There's no insulation on these interior walls.  I can't think of any good reason not to let the exhaust fan (slightly) pressurise the wall.  The ceiling is sealed, the bottom is a slab.
 
Just mount it to the wall on one side, and cut a hole and put a grate on the other, no duct? 
 

wkearney99

Senior Member
I've always started with just passive convection.  A grate low on the door and then another at the ceiling level.   

The downside to a fan is you're then pulling in any airborne dust too.  Which leads to thinking about adding a filter, which restricts flow and then becomes yet another danged thing to maintain.  With passive you're at least not actively yanking dust into the space.

If you were going to duct it elsewhere I've always like the Fantech brand of in-line fans.  We've got them on all our bathrooms.  This to avoid having an ugly-looking fan unit making a racket in the space.  They're nearly dead-silent at the intake. 

But for a closet venting to the adjacent room I'd look more toward a cabinet ventilating fan setup.  One with a thermostat control would be where I'd start. 

Just don't forget about it if the space is going to be allowed to go unconditioned for extended periods like vacations.  This is a point that gets forgotten sometimes.  Your adjacent room AC is off, but the gear is still on, cranking heat and has no way to lower it.

And from a safety perspective, with modern houses if you add any exhaust fans you need to make sure you've got enough make-up air.  Older houses aren't typically a problem, but newer ones are often tight enough that a fan left running can lead to accidental problems with interrupting the exhaust flow from gas water heaters and furnaces.  I have to remind my wife not to light the fireplace in the family room if the hood over the cooktop is running.  There's "just enough" pull from the fan hood to overcome convection up the chimney as the fireplace gets going.  Once the fire is going it's not a problem, but for the first few minutes... ugh.. the smoke alarms going off....
 

upstatemike

Senior Member
Linwood said:
I don't have an outside wall, but if it fits....
 
After writing this I realized I have another question... maybe I don't need a duct.  If I go into the wall on one side, and just put a grate on the other.... 
 
There's no insulation on these interior walls.  I can't think of any good reason not to let the exhaust fan (slightly) pressurise the wall.  The ceiling is sealed, the bottom is a slab.
 
Just mount it to the wall on one side, and cut a hole and put a grate on the other, no duct? 
 
I would not pressurize the wall. Any humidity = mold = bad.
 

LarrylLix

Senior Member
The heat may be beneficial in the summer, but detrimental in the summer when you have to use the A/C to remove it to outside. This is climate dependent where you live. The small amount of heat dispersed throughout the house may be insignificant also.
 
When you vent to outside it has to come in through door/window/receptacle seal leaks anyway.
 

Linwood

Active Member
wkearney99 said:
I've always started with just passive convection.  A grate low on the door and then another at the ceiling level.   

The downside to a fan is you're then pulling in any airborne dust too.  Which leads to thinking about adding a filter, which restricts flow and then becomes yet another danged thing to maintain.  With passive you're at least not actively yanking dust into the space.

If you were going to duct it elsewhere I've always like the Fantech brand of in-line fans.  We've got them on all our bathrooms.  This to avoid having an ugly-looking fan unit making a racket in the space.  They're nearly dead-silent at the intake. 

But for a closet venting to the adjacent room I'd look more toward a cabinet ventilating fan setup.  One with a thermostat control would be where I'd start. 

Just don't forget about it if the space is going to be allowed to go unconditioned for extended periods like vacations.  This is a point that gets forgotten sometimes.  Your adjacent room AC is off, but the gear is still on, cranking heat and has no way to lower it.

And from a safety perspective, with modern houses if you add any exhaust fans you need to make sure you've got enough make-up air.  Older houses aren't typically a problem, but newer ones are often tight enough that a fan left running can lead to accidental problems with interrupting the exhaust flow from gas water heaters and furnaces.  I have to remind my wife not to light the fireplace in the family room if the hood over the cooktop is running.  There's "just enough" pull from the fan hood to overcome convection up the chimney as the fireplace gets going.  Once the fire is going it's not a problem, but for the first few minutes... ugh.. the smoke alarms going off....
 
I'll look at Fantech though in a brief look there were a LOT of fans but i did not see this category?  Any specific advice? 
 
I will not vent outside, so make-up air is not an issue.  It's both inconvenient to vent outside plus very inefficient.
 
This is SW Florida -- we never go un-conditioned, especially in summer, or everything rots and mildews.  I also have some furniture that really does not tolerate humidity changes well, so I tend to keep things pretty steady inside.
 
upstatemike said:
I would not pressurize the wall. Any humidity = mold = bad.
 
I'm not following that.  Are you saying I'll pump air into the wall which will increase the wall's humidity level?  It's an interior wall, it is pretty much at interior ambient temperature.  I guess in theory it could traverse the 15' or so of intervening studs to an exterior wall, get through the insulation there, but probably 360 days out of the year that wall is hotter than the interior not colder.
 
The bigger issue is the plate at the top (metal) adjacent to the attic, but (a) insulated already, and (b) same situation really as sheet rock has now, and (c) also almost always hotter, though occasionally not.  But really not different than the sheet rock at the ceiling.
 
Or am I misunderstanding the source of the issue? 
 
I can build a duct I guess.  Just didn't want to.
 
LarrylLix said:
The heat may be beneficial in the summer, but detrimental in the summer when you have to use the A/C to remove it to outside. This is climate dependent where you live. The small amount of heat dispersed throughout the house may be insignificant also.
 
When you vent to outside it has to come in through door/window/receptacle seal leaks anyway.
 
SW Florida.  A/C runs almost constantly, even in winter it runs daily just not quite as continuously.  I considered just ducting a return in the closet (it is very convenient), but during the winter there are times with many hours may go by without it running.  Almost never a full day, though it happens.
 

wkearney99

Senior Member
I think you're fine just exchanging with adjacent conditioned interior air.  I'd start passive but have a plan for active.  Especially since you're only seeing 80F at this point.  
 

LarrylLix

Senior Member
Linwood said:
<snippage>
 
SW Florida.  A/C runs almost constantly, even in winter it runs daily just not quite as continuously.  I considered just ducting a return in the closet (it is very convenient), but during the winter there are times with many hours may go by without it running.  Almost never a full day, though it happens.
You shouldn't have any trouble with humidity into your attic and it may save you a few A/C bucks.. In Canada that would be a no-no as you would ice  up your insulation.
 
Bills concept and solution (above) sounds the best to me. Just make sure your natural ventilation is way above (height) the intake vent.
 
I have had two routers go nuts inside a small cabinet with vent holes in the back now. Those dual core 1GHz CPUs in small boxes don't like a higher ambient. They both crashed regularly at about 37 degrees C, even with the cabinet doors open. Despite both ASUS AC1900, and Netgear AC1900, being able to sit horizontal on a shelf, both crashed until stood up (for the Asus) or mounted on a vertical wall (for the NetGear).
 
Strangely, I maintain my room temp about 23 c summer and winter, but somehow they knew what the temperature was outside. :) Maybe humidity levels?
 

Linwood

Active Member
wkearney99 said:
I think you're fine just exchanging with adjacent conditioned interior air.  I'd start passive but have a plan for active.  Especially since you're only seeing 80F at this point.  
 
Well, there's no computer in there yet (a rPi doesn't count).  I need a computer as NVR and NAS for backup, so it will be churning 24x7 with video streams.  That will be the main source of heat.  Right now just a switch and two routers and a UPS, so it shouldn't be hot.  Though I purposely shut the door tight last evening to see how hot it would get (and to test a Zooz sensor at the same time). 
 
I'm just not thinking passive will do it, but it sure would be nice.  Certainly quiet.  Maybe I'll pick a fan and make the right size holes and grill and see what happens without the fan.  The bottom of the door is about 3/4" so it's likely adequate for intake already.
 

LarrylLix

Senior Member
I played with a larger Muffin fan and an AC adapter with a selectable voltage switch to vary my fan speeds while using a CAO TAG to monitor the temps.
 
My Rpi3 creates a lot of heat when it starts displaying HD video. Not more than the PS at 12.5W,  Then there is some from the PSU also. I am sure but when that is contained it rises slowly to high temps. It must be kept vertical and have heat sinks on all the chips or they crap out too. It took my some time to figure out where the little thermometer being displayed on the top right of my monitor was coming from. :)
 

JimS

Active Member
If you make a hole in the wall for a fan it would be easy to slip some short 2 x 4s in to line the "duct".  A few dry wall screws to hold them could be covered by the grills.  Would make it much more solid to mount the fan also.  I have also wondered about the heat.  I am putting my things in a large cabinet.  Nothing with a lot of power - a few routers and Pi boards, a ups...Passive ventilation will probably be adequate if I make the openings fairly large for a little more flow.
 

BraveSirRobbin

Moderator
My friend had the same problem and he replaced his door with a louvered one.  That plus a small recirculating fan inside the closet solved the problem.
 

LarrylLix

Senior Member
Which is cheaper and easier? Constant monitoring with a notification protocol set up and some smarts, or a thermostatically controlled power vent system?
 
Trouble is what works today may quit working tomorrow, or next year, or next sunny day, without warning and cost you lots of time. Network flakiness can be really hard to detect..
 

pete_c

Guru
New home build put the wiring closet in the laundry room in a one story elevated ranch in FL around 1990-2000 (took a year to build).  In the closet installed a Leviton HAI Pro 2 media panel and a Leviton Media panel around 2003-4.  In the Leviton can put a modem, switch, Verizon FIOS combo (AP off) and patch panel (telephone and network).  Above the can near the ceiling put a DD-WRT WRT54G that was used as a firewall and WAP. 
 
Never did put exhaust fans or used any sort of passive cooling.  The Leviton cover remained in place for over 10 years.  Never had a problem with it.
 
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