Benchmarking: Finding What Buildings Really Use
by Mame Sussman, COLUMBIA UNIVERSITY EARTH INSTITUTE, April 26, 2010
Within the past two years, two cities in the U.S. have passed ordinances mandating that existing buildings benchmark their energy usage. Benchmarking requires a building owner to report energy use data which can then be compared to data from buildings of a similar size and function and to past data from the same building. These ordinances push green building one step further than most municipal laws, by not only enforcing standards on new construction, but regulating existing buildings. As building stocks take a long time to turn over, regulating existing buildings’ energy usage is crucial to attacking the problem of climate change. This article takes a closer look at the two ordinances and some of the similarities and differences between them.
Washington, D.C. was the first city in the country to pass an energy benchmarking law. The Clean and Affordable Energy Act of 2008 requires that all buildings owned or operated by the District or any of its instrumentalities that are at least 10,000 square feet be energy benchmarked by 2009.[1] Privately-owned non-residential buildings of at least 200,000 square feet must be benchmarked annually starting in 2010. The size threshold for privately-owned buildings drops by 50,000 square feet each year so that by 2013 all non-residential buildings of at least 50,000 square feet will require benchmarking.
New York City passed a benchmarking law in 2009 as part of the Greener, Greater Buildings Plan.[2] This law requires that buildings larger than 10,000 square feet owned by the city or where the city regularly pays all or part of the annual energy bills, begin annual energy and water benchmarking by May 1, 2010. Covered buildings, defined as buildings more than 50,000 square feet, two or more buildings on the same tax lot that together exceed 100,000 square feet, or two or more buildings held in condominium form of ownership governed by the same board that together exceed 100,000 square feet, must benchmark their energy and water usage annually starting May 1, 2011.
Both laws require city-owned buildings to be benchmarked within a year of passage of the ordinance. D.C. allows a phase in period for privately-owned buildings, while New York is more stringent and requires that all buildings over 50,000 square feet are benchmarked two years after passage. D.C.’s phase in approach won’t accomplish this until five years after passage. In addition to requiring benchmarking sooner, the New York City law is more comprehensive because it includes residential as well as non-residential buildings and certain buildings that are less than 50,000 square feet on their own.
New York City’s law also requires more of the benchmarked buildings than D.C.’s in that it requires water benchmarking as well as energy benchmarking. However, benchmarking is only required for water usage for buildings for which the Department of Environmental Protection has equipped automatic meter reading equipment and the equipment has been in operation for the entire previous calendar year.
Both laws conduct benchmarking through the U.S. Environmental Protection Agency’s Portfolio Manager Tool, a free online benchmarking program that compares energy and water usage to past data from the building and to data from other buildings of similar sizes and uses. The New York City law encourages utility companies to upload energy usage data directly but does not require it. However, the New York City Department of Environmental Protection must directly upload information on all water usage at buildings equipped with automatic reading equipment. [Read entire post]