HP liked EYP's work so much that it decided to a year ago, transforming it into a new division that helps HP clients plan the building of energy efficient data centers or retrofit existing ones.

Financial institutions are particularly interested in reducing energy use, as data centers can use 30% of an organization's energy even while taking up just 5% of its square footage, Kosik says. Retrofitting existing data centers is often worthwhile but extremely difficult, he adds.

"It's expensive and you can't turn the thing off. You're basically doing open heart surgery on a patient that's running around the block," Kosik says.

Going after low-hanging fruit can sometimes have a big impact, though. Kosik notes that many data centers waste power simply by keeping the thermostat too low.

"In traditional data centers, you walk into them and they're like refrigerators," he says. "That's really not the way to do it. If we raise that temperature five of 10 degrees you could save easily close to 40% on power for your cooling systems. Climate has a huge impact on data centers."