A survey of energy consumption of New York City’s largest buildings aims to encourage and guide building owners toward pursuing energy retrofits. The report, released by the city's Office of Long-Term Planning and Sustainability, tracked the energy use of more than 15,400 buildings in 2010 and found that those that fell in the bottom 10% consumed three to five times more energy than their more energy-efficient counterparts.
Some of the power hogs used up to five times as much electricity, natural gas, heating oil and steam as others of comparable size or purpose. The report says that if poor-performing buildings improved their efficiency to just the median level of energy use in their categories, the city’s energy consumption would decline by at least 18% and greenhouse gas emissions would be cut by 24%. The city will use the data to assign scores to individual buildings on their energy use and publicize them to further encourage property owners to make necessary improvements.
(http://www.nytimes.com/2012/08/03/nyregion/wide-differences-found-in-large-buildings-power-use.html)