Everyone generally knows that data centers are the big energy hogs in the building universe. In some data centers, nearly half of the power goes to air conditioning (which counts toward power consumed by a building and its operations). Put another way, that means that the air conditioners use as much power as the computer systems (which can be counted under another energy budget). But what are the second worse types of facilities? Probably scientific labs, says Lynn Olechnowicz, a senior associate at Perkins + Will, an architectural firm known for LEED and energy efficient designs. Labs typically need to be equipped with fume hoods, which suck away chemicals or loose biological material. "All of the air is conditioned air" as a result, she said. To reduce power, building owner or lab managers need to adopt control systems that will only condition air when necessary, rather than all of the time. Air conditioning accounts for a substantial portion of the outrageous amount of energy consumed in running buildings. It ranks up there with heating and lighting. And, like heating and lighting, large gains in efficiency can likely be made over the next few years by replacing old technology with new, efficient products. Air conditioning, in fact, has knocked out waste heat as my favorite topic. If anything, it makes me a fascinating conversationalist. Olechnowicz, by the way, will be one of the speakers at our Green Building Summit coming in June.