Benchmarking: Still Going Strong

Recently, and with little fanfare, New York City released its third report on the data gathered through the benchmarking program created by Local Law 84 of 2009. As before, data was required for buildings over 50,000 square feet, and compliance is up (again), with 89 percent of multifamily buildings reporting, rising from 80 and 81 percent in previous years.

In a disturbing twist, Superstorm Sandy seems to have lowered reported carbon emissions. While median energy use intensity (EUI) in 2010 and 2011 was 137 and 138 thousand Btu per square foot, in 2012 the same building set had a median EUI of only 121 kBtu/ft2—a 12 percent drop. The drop in commercial properties was even more extreme, from 234 and 220 kBtu/ft2 in 2010 and 2011, dropping 13 percent to 191 kBtu/ft2 in 2012. The city’s analysts pored over the data, and found the declines were less extreme with more stringent data cleaning. In the end, however, they couldn’t find any reasonable driver behind this decline other than the large number of buildings knocked out of action for the last three months of 2012 by the storm. We hope we can find better ways to lower emissions in the future.

Three years of data
Three Year Median EUI for Office and Multifamily Properties (source: NYU and NYC Mayor’s Office)

As a result of this decline, the city did better than average in 2012 compared to the rest of the country. Before we take much pride in this, however, remember that the pre-Sandy EUIs were very close to the national averages and indicate that, like everywhere else, we have a lot of room for improvement.

Another curious statistic comes from the report’s water data. Hotels in New York use 25 percent more water than the national average of Portfolio Manager properties on a square foot basis. On the other hand, if you look at usage per room, median water use in city hotels is 12 percent below the national average. How do they do it? Smaller rooms! Individual fixtures may be water efficient, but overall city hotels use more water because they pack in more people. It’s a lesson in picking the right statistic to use when evaluating benchmarking data.

Finally, we are getting rid of heavy (and dirty) heating oils, with use of number 4, 5, and 6 oils declining from 30 percent of the multifamily market in 2010 to 23 percent in 2012. This means cleaner air and fewer lung-related illnesses for all of us, and is a positive note to end on. For lots more details, download the full report online.

About the authors

Richard Leigh
Richard Leigh is a Visiting Professor of Physics at Pratt Institute, primarily teaching courses in building science. He formerly served as Urban Green's Director of Research, where he managed research projects including the 2016 New York City Auditing and Benchmarking Report for 2013 data and 90 by 50, showing that New York City can reduce its greenhouse gas emissions 90 percent below current levels by 2050.