We are trying to determine the right power and cooling for a new server room which would be about 350 sq ft., our power is 220V. We are initially only planning to start with a single rack with potential of expanding upto 4 or 6. The rack would have 10-12 Dell Poweredge 630/730 1U servers with 2 Cisco 3850 switches and a PS6200 series Equallogic SAN. I've read several different sources and discussion boards and a lot of it becomes confusing. Some people say never to go with the nameplate power rating of a device, others say that's what your device can draw maximum so that should be used, etc. Another aspect I read was about power per rack which seemed to be a good estimation approach. It stated low density racks are about 4-5kW, medium density about 8-10kW and high density about 12-15kW, does this sound right? Looking at the Dell servers, it shows 3 different types of power supplies: 495 W, 750 W, or 1100 W. Most places I read suggested 300 watts per server. The dell PS6210 SAN lists 1080W and the cisco switch power supplies range from 350W to 1100W

I've tried to do some calculation and came to about 4kW (300W x 12 and rounding up) for servers, another 3.3kW for the 2 switches and the SAN unit, so roughly 7.5kW for the rack, does this estimate seem right? Based on only 10-12 1U servers I was thinking its a low density configuration and should be about 4-5kW.

For cooling should I just multiply this by 6 (for 6 potential racks) and convert that to tons or BTU ? That would actually mean 7.5kW x 6 = 45kW which is about 12.7 tons of cooling, that can't be right for such a small server room.

I've also gone through APC's UPS calculating tool which showed me only 750-1000VA models that would be able to provide UPS to one rack. There are also 2 whitepapers by APC which I'm currently trying to read and understand properly.

Any help/suggestions would be greatly appreciated. Thanks

  • It's a lot to absorb if you've never done it before. A good local contractor or consultant can provide some information and site-specific recommendations.
    – ewwhite
    Commented Nov 24, 2016 at 5:42
  • Thanks emwhite. I do realize that its a lot and there are professionals who do this for a living. However, this is a small business type situation, we want to have at least the information and its basic understanding to make sure we are not completely off base.
    – jackie1100
    Commented Nov 24, 2016 at 5:58
  • You are already doing rough estimates and reading up on solutions, which will help make an informed evaluation of a professional's help. Yes, it will require very dense power and cooling. Yes, you want monitoring of your power and cooling systems. Commented Nov 27, 2016 at 16:59

2 Answers 2


There are times when it's best to involve people with specific knowledge and expertise in a particular area. You can ask this question on sites like this until you're blue in the face but you'll never really know if the answers you're getting are "really right", because you don't have the requisite knowledge and expertise needed to evaluate those answers. It's great that you want to learn more about this, so take @ewwhite's suggestion and hire someone to assist you so that you learn it the right way from someone who actually knows this stuff. It's no knock on you or your team to say "We don't know enough about this and need to get outside help from an expert." Smart people follow that road. People who are... well... less smart, try to fudge it on their own and often find that they've wasted a lot of time, money and energy building something that winds up being the wrong thing.


Have you looked into Dell OMPC it will

  • Measure energy consumed by IT equipment at a server, rack, row, or room level Mitigate Risk by reducing power consumption per a pre-defined policies that maximize the uptime of business critical applications by reducing non-critical consumption Increase data center density by identifying racks with equipment not using the power capacity that has been wired into it. Reports containing CPU usage and power consumption that can be used for: Chargeback – physical and VM Workload balancing based on power consumption Identifying rack space for server installations

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