Nerval's Lobster writes "The Green Grid, a nonprofit organization dedicated to making IT infrastructures and data centers more energy-efficient, is making the case that data center operators are operating their facilities in too conservative a fashion. Rather than rely on mechanical chillers, it argues in a new white paper (PDF), data centers can reduce power consumption via a higher inlet temperature of 20 degrees C. Green Grid originally recommended that data center operators build to the ASHRAE A2 specifications: 10 to 35 degrees C (dry-bulb temperature) and between 20 to 80 percent humidity. But the paper also presented data that a range of between 20 and 35 degrees C was acceptable. Data centers have traditionally included chillers, mechanical cooling devices designed to lower the inlet temperature. Cooling the air, according to what the paper originally called anecdotal evidence, lowered the number of server failures that a data center experienced each year. But chilling the air also added additional costs, and PUE numbers would go up as a result."