There were a lot of questions asked about server cooling, but I can't seem to find the one that fits our needs. Our server rack/cabinet is situated in the mail room, which can get extremely hot in the summer times. Plus, because we're on the top floor, 14th out of 15, we get most of the heat. There are three servers on top of each other, two standalone and one with rack. What would you suggest to get? It is not in an enclosed area. The rack is in the mail room, which is about 900 ft sq. Should I get one of those portable ACs (12000 btu), but it can only cool space up to 400 ft sq. Does placing it closer to the server could solve the problem? I would like to be cost effective and cannot afford server cabinets with water cooling...

Any thoughts?

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    I'm not any kind of datacenter/cooling/thermodynamics expert so take this suggestion as the crazy idea that it is, but what about using cubicle walls or something similar to "fence in" the server section of the room, which should help reduce the volume of air that needs to be cooled, or at least hold some of the cool air in place until it heats enough to escape over the cubicle walls? – DerfK Feb 17 '11 at 23:48

That's a tough situation, usually server rooms are enclosed or at least have some sort of duct work with an intake/exhaust system. If the servers are directly on top of each other (within 1U) I would seperate them a bit more. If you have the room to (assuming a full 42U server rack) put 5-10 U between each server. That will stop heat from building up directly from each other.

If possible, get an industrial fan/box fan and angle it so that you have air blowing through the intakes of the servers (usually the fronts). Having an exhaust fan close to the back of the servers wouldn't be too bad of an idea either.

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    Be aware, this procedure is NOT recommended unless you have blanks to fill the empty U's between the server due to air recycling between servers. – pauska Feb 18 '11 at 9:59
  • I might use the industrial fan solution, but the air still will be warm and will not reduce the temperature. For some reasons, the ductwork does not go through mailroom. And the AC breaks down very frequently... This is an old NYC building! – servercooler Feb 18 '11 at 22:25

There are solutions for this. If you do have a rack, something similar to this unit from APC:


Would work. These provide in-rack cooling, which sounds like it'd work for your environment. There are other vendors out there, so see what works for you.

  • Yeah this is worth checking out, although I remember that these APC per-rack AC units are quite expensive. I'm guessing someone with his rack in an overheated mail room probably doesn't have the money for something like this. Still, worth considering. – Phil Hollenback Feb 18 '11 at 0:16
  • Yeah, I've looked at this solution, but I believe these cabinets are at least $5k or more. – servercooler Feb 18 '11 at 22:16

What about rigging up your own enclosed cooling solution? You could bang up some sort of enclosure with plywood, plastic, whatever. Ideally you could get the cold air flowing into the front of the systems, and then completely separate the rear. The rear could just exhaust out into the hot room. You'd be essentially be creating a super janky hot/cold aisle setup. You could run the input hose from the portable cooler right into the front of your enclosure.

Be aware that all AC units extract water from the air as a side effect of cooling it. Permanent units have a drip mechanism that connects to your building plumbing. Portable units have some sort of bucket which must be emptied on a regular basis to prevent overflow. However you design this setup, make sure you aren't accidentally creating a flooding problem later on.


As others have commented, this sounds like you'd be looking for a cheap and dirty solution, so:

  • Do what you can to reduce the thermal load on the room, e.g. put reflective film on the windows, make sure there are good reflective blinds.

  • If you can put a standard window A/C unit in the mail room and shut the door, that might be sufficient.

On the one hand, if the window A/C isn't possible, I'd be tempted to just go with a floor model, but you still need to vent that somewhere and deal with the condensate. On the other hand, before getting too elaborate with any quick and dirty system, I recommend reading this classic article. Sometimes you really need to do it right, and even though you're talking about a small server setup, maybe you should look at moving them to a room that's already properly air-conditioned, or getting a rack with fans to ensure proper airflow.

  • On the hindsight, the mailroom is in the middle of the floor. It does not have any windows. But I cannot keep the door shut due to frequent deliveries. I am thinking of moving it to my office, but I am not sure how would I deal with all the cables, switch, and the modem, router, etc.... – servercooler Feb 18 '11 at 22:31
  • Classic article not found. – SQB Oct 13 '16 at 12:25

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