Seventy percent of electricity in a data center powers equipment other than IT gear, according to American Power Conversion (APC), a vendor of backup products and service in West Kingston, R.I.\n\nIf you're considering how a green data center may save you money, check out APC's estimates of power usage in a typical 1 megawatt data center: \nAir-cooled chillers: 33 percent\nUninterruptible power supplies: 18 percent\nComputer room air conditioners: 9 percent\nPower distribution units: 5 percent\nHumidifiers: 3 percent\nSwitches: 1 percent\nLighting: 1 percentJust 30 percent of incoming electricity goes to IT servers. That's a significant portion, but by no means the majority. The next time someone tries to sell you superefficient "green" servers, listen. But realize that that's only one factor in building an environmentally sound data center. Also, the way you have your servers\u2014and chillers, air conditioners and humidifiers, too\u2014placed on the floor can waste or save power as well. Installing air conditions at the room's perimeters, for example, may bring in the right number of cooling units. But using fans to push that cold air close to the racks of blade servers in the center of the room will use extra power and cost extra money.