My organization is in the process of looking for new space in Manhattan. We have 25 employees and are looking at offices that are around 7,000 sq. ft. I don't anticipate us ever needing more than a single rack (which puts us squarely in the server closet realm) and our cooling needs are ~5,000 BTUs.

What should I be looking for in terms of supplied cooling? Is it reasonable to expect a server closet to have a separate air coditioner? Do server closets have ventilation for tenant provided portable AC units? Should an adequate building HVAC system cover my server cooling needs?


  • 1
    When you say "rack" do you mean "rack enclosure", or "open posts rack"? For open posts, ITGuy24 has it, use a small dedicated split system. For an enclosure I'd go with a rack mount unit (your rack supplier likely makes a unit that fits at the top or bottom of your rack). – Chris S Jul 2 '10 at 17:23
  • No rack right now, just towers. If the servers are in a dedicated room with good AC, it'll be an open rack, otherwise an enclosure. – Helixso Jul 6 '10 at 18:22

Communicate your requirements to your broker. With the occupancy rates what they are, a landlord might be likely to include this in the cost of the buildout for occupancy. Most buildings are not going to be equipped to handle that sort of cooling with their current system. I think you are severely underestimating your heat load.

A person is generally considered to be 400btu. Even some of the smaller Dell 1U servers claim 850-1400 BTU as a minimum. It wouldn't take too many servers to overrun 5000 BTU of cooling. I can tell you that the data center where we are complains of our heat bloom and has put in much higher airflow tiles in the floor. Our current generation servers are dual quadcore Xeons, green certified, 90% efficiency power supply, and they are rated at 1300 BTU. A rack of those not including the support hardware (switches, etc) is 41.6k BTU.

1 watt = 3.4(1something) BTU if I remember the math correctly.

In NYC, you might be able to get hooked into the buildings chilled water supply to put in a fairly small but efficient AC unit. Remember that an air conditioner moves heat from one place to the other. Where you are providing cool air into your closet, that hot air needs to be exhausted somewhere either in the plenum, through ducting outside the building, into the neighboring office space (if you don't like them and they are a competing webapp company).

Recalculate your heat load, have your broker make sure that the space will have a server closet with adequate cooling, or, ask for a concession and build it yourself with a qualified contractor. Replacing hardware that overheated is a frustrating process as the units will not fail in predictable manners.

  • I wish I were underestimating. I'd calculate the current heat output at 3,300 BTU, including networking, UPS and vendor provided equipment. Although we have two servers right now, it's possible we may have as many as four in the future. – Helixso Jul 6 '10 at 19:03

I would recommend a dedictated ductless system, like the Mitsubishi Mr. Slim PK Series. Since you are in Manhattan, one of the key things to look at is a unit that can run in very cold tempatures. Most AC units have problems as soons the temp gets below 32F/0C.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.