New York City is characterized by its demanding construction codes. The NYC Energy Conservation Code applies in the case of energy efficiency, and its most recent version was published in 2016. However, the city government also leads by example: Local Laws 31 and 32 place additional energy conservation requirements for city-owned buildings, and are much more demanding than even the 2016 edition of the Energy Code. Although these laws are only mandatory for city buildings, property owners can use them as a reference if they want to go the extra mile in terms of energy efficiency.
The main objective of LL31 and LL32 is achieving major energy savings in city-owned buildings, which also leads to a significant reduction in polluting emissions. However, the laws were also created to demonstrate commitment and prove that energy efficiency is possible. In addition, they will help develop the technical know-how required to make the entire city more efficient and less polluting.
This article will provide a brief overview of LL31 and LL32. Remember they do not apply for the private sector, but they provide an idea of the building performance levels NYC is aiming for.
Local Law 31 was created after analyzing the results of building benchmarking, carried out according to the Greener, Greater Buildings Plan. Benchmarking has revealed how the largest buildings in NYC use energy and water, allowing the calculation of metrics such as the Energy Use Intensity (measured in thousands of BTU per square foot per year, kBTU/sf/yr).
Based on the median EUI values collected through benchmarking, LL31 requires city-owned buildings to cut their energy use to 50% of this value or less. Alternatively, a building can comply through energy modeling, by demonstrating that it consumes at least 50% less energy than a similar property built according to ASHRAE 90.1 2013. Benchmarking data has revealed that both approaches result in roughly the same level of energy performance. Buildings that consume 50% less energy than other constructions of their type are referred to as low energy intensity buildings.
However, it is important to note that the LL31 requirements only apply in three cases: new constructions, building additions and major renovations. In other words, if no additions or major renovations are planned for an existing city-owned building, LL31 does not impose an upgrade project. In addition, the NYC Mayor can establish alternative targets, a long as they are equally stringent.
Local Law 31 also requires that city building conduct a mandatory feasibility analysis for the following projects. Note that the projects themselves are not mandatory, only the analysis.
By 2030, all new constructions must be designed to use at most 38 kBTU/sf/year, while major renovations must be designed for no more than 42 kBTU/sf/year. The lessons learned from designing and building projects according to LL31 will be gathered and published in reports at three-year intervals, starting in 2019.
While LL31 focuses on energy use intensity, LL32 focuses on LEED certification. New constructions owned by the city with a budget of $2 million or more must earn at least LEED Gold certification, and the law also applies for major renovations. A similar law already existed since 2005 (LL86), but it was much less demanding, requiring only basic LEED Certification. It is also important to note that, while LL86 was based on LEED v3, LL32 used LEED v4.
Requirements for the residential sector are different, where buildings must meet the Enterprise Green Communities Criteria (NYC version). LL32 also added occupancy classifications that were previously exempt: Industrial, Factory and High Hazard. However, given the added challenge in these occupancies, there are exceptions and alternative compliance paths. Another key difference is that LL86 only required 50% of the buildings to be actually certified by LEED, while LL32 raises the requirement to 100%.
In general, LL31 is more demanding than LL32, so many buildings can automatically cover many LEED Gold requirements by focusing first on LL31.