New York City has updated its Energy Conservation Code, which mandates stricter energy and sustainability requirements for both new construction and existing commercial buildings. The new requirements went into effect on May 12, 2020 and place even greater pressure on building owners to comply with NYC Local Law 97 mandates to reduce building-based GHG emissions. The new 2020 ECC can be accessed here: https://www1.nyc.gov/site/buildings/codes/2020-energy-conservation-code.page.
Under the updated code, new construction and modifications to existing buildings must adhere to more rigorous fenestration and insulation requirements. Historic buildings and storm windows are exempt from the new legislation. The table below shows the revised U-factor and Solar Heat Gain Coefficient (SHGC) requirements for new commercial building windows in NYC and while “storm windows” are exempt, Thermolite can provide an interior glazing option that can meet or exceed the proposed values for new windows.
Building owners have three options when it comes to facing the demands of the new NYC energy code. The pros and cons of each are detailed below. Currently these apply only to building owners in NYC, but with the growing concern over GHG emissions and sustainability, other major cities are likely to pass similar resolutions in the near future.
Option One: Maintain Your Windows
Building owners have three options when it comes to facing the demands of the new NYC energy code. The pros and cons of each are detailed below. Currently these apply only to building owners in NYC, but with the growing concern over GHG emissions and sustainability, other major cities are likely to pass similar resolutions to Local Law 97 that was passed in 2019 which mandates 40% savings in existing buildings starting in 2024.
Option Two: Replacement Windows
Building owners who want to improve a facility’s fenestration system often first consider replacement windows. While new high-performing windows will reduce GHG emissions, the greatest drawback to this option is cost. Removing and replacing the windows of a large commercial building is a deep renovation that can cost upwards of $100M. In many cases, replacement windows are not an option because it requires displacing building tenants for extended periods of time. Replacement windows will also need to meet the performance requirements of the new NYC energy code.
Option Three: Interior Window Retrofits
Interior window retrofits, also called secondary glazing or “storm windows” in residential applications, are the most convenient, permanent and cost effective option for improving a building’s energy performance. Window retrofits, which can be installed quickly and without tenant disruption, are often times 90% less expensive than replacement windows for high rise buildings. In addition, secondary glazing is exempt from NYC’s energy code so you don’t have to worry about meeting U-value and SHGC requirements. That said, window retrofits often exceed the new energy code performance standards and have been shown to reduce GHG emissions by an average of 20%, which will help you meet the benchmarking targets of Local Law 97.
An example of the improvement Thermolite can provide can be seen in this 45-story skyscraper in midtown Manhattan. The building’s existing single pane window system had a U-value of 1.083 and a SHGC of 0.747 and tested per window air infiltration of .71 cfm/ft2. Thermolite’s RetroWAL Gold system improved the improved the U-value to 0.274 and the SHGC to 0.488 (see thermal images below) and reduced the air infiltration to .02 cfm/ft2. Please note that this was an ideal window condition for our application and not all windows perform at the same level.
Thermolite’s Free Energy Savings Assessment Calculator for NYC Buildings
Understanding New York City’s energy code, Local Law 97 and how both affect building owners can be confusing. We’re here to help. Thermolite has extensive experience improving the energy performance of both large and mid-size commercial and federal buildings in NYC. In addition to helping you navigate the continually changing laws and regulations overseeing new and existing construction, Thermolite has developed a cost-effective tool to help you determine the energy savings you can expect from various building envelope improvements. If you own or manage a commercial building in NYC, contact us today to request a free energy savings assessment.
