In a city that takes pride in its historical roots, Boston’s older buildings are significantly more energy efficient than its newer facilities.
The recently released disclosure – Energy and Water Use in Boston’s Large Buildings, 2013 – is an overview of the first year the city offered private sector reporting in addition to municipal facilities. Over 175 million square feet of floor area is monitoring energy use, water consumption and greenhouse gas emissions. The included properties represent approximately 45% of the energy used by all non-residential buildings in Boston.
To normalize the data, all users receive a site EUI, as well as a source EUI, which includes the losses that take place during generation, transmission and distribution of energy to represent the raw energy required per square foot. Many buildings also receive an ENERGY STAR score and use the online Portfolio Manager to track their progress.
Key findings based on the 820 participating buildings:
- Office buildings are the most prevalent type, accounting for 42% of the floor area, followed by hospitals and higher education buildings at approximately 10% each.
- Older buildings generally perform well. For offices built in the 1930s and 1940s, for example, the EUI is roughly 45 kBTU per square foot and businesses constructed in the 1910s are as low as 42. By comparison, properties from the 1970s skyrocket to 95. The reason for these energy disparities is because many of the vintage properties have masonry construction rather than glass curtainwalls.
- The largest buildings are more likely to report their performance, with facilities between 500,000-600,000 square feet leading the way with 100% compliance.
- Laboratories report the highest site EUI by building type, followed by offices, higher education and hospitals.
- Median ENERGY STAR scores exceeded national averages for offices, financial institutions and dorms.
- Offices and hospitals are the biggest water users at 23% and 22% respectively. Those two types also account for the highest greenhouse gas emissions.
In 2013, Boston enacted the Building Energy Reporting and Disclosure Ordinance, which targeted large buildings over 50,000 square feet. In 2016 and 2017, buildings between 35,000 and 50,000 square feet will begin to submit their data and mark full implementation of the ordinance. In just two years, over 40% of non-residential floor space will report, though this comprises only a small fraction (less than 4%) of total buildings. Continuing improvements by all commercial spaces will help Boston reach its citywide goal of 25% emissions reduction by 2020 and 80% by 2050.