Local Law 97 NYC (LL97) - Climate Mobilization Act


In an effort to combat climate change, New York City passed Local Law 97 of 2019, also known as the Climate Mobilization Act. This law sets strict carbon emissions limits for buildings within the city, making it one of the most ambitious climate laws in the world. This article will provide an overview of Local Law 97, its requirements, and how building owners can comply with it.

Summary of Local Law 97 of 2019

Local Law 97 mandates that buildings over 25,000 square feet must reduce their carbon emissions by a specified amount. The law is designed to help New York City reach its goal of reducing greenhouse gas emissions by 80% by the year 2050. To achieve this, Local Law 97 sets annual carbon emissions limits for buildings, starting in 2024. These limits will become increasingly strict over time, with the ultimate goal of reaching a 40% reduction in carbon emissions by 2030 and an 80% reduction by 2050.

Buildings over 25,000 square feet accounts for nearly 60% of New York City’s build area, circa 50,000 buildings across residential and commercial properties.

By 2030, a large number of buildings will need to undergo significant retrofits or find alternative means of compliance, as they are producing carbon emissions above the limits set by Local Law 97.


Buildings Affected by Local Law 97

Local Law 97 applies to all buildings in New York City over 25,000 square feet, with a few exceptions. Buildings that are primarily used for manufacturing or storage are exempt, as are buildings owned or operated by the government. Buildings that are already subject to other emissions reduction programs, such as the Regional Greenhouse Gas Initiative, are also exempt.

There are also special compliance guidelines for certain buildings such as rent regulated and affordable housing. These types of buildings may have limited resources to invest in energy efficiency upgrades, so the city has developed specific programs and incentives to help them comply with the law. Building owners can receive technical assistance, financing, and incentives to make energy efficiency improvements. The city also offers a compliance extension for these types of buildings, giving them until 2025 to meet the new emissions limits.


Local Law 97 Timeline

The timeline for Local Law 97 is as follows:

  • December 31, 2024: Buildings over 50,000 square feet must meet their first set of emissions limits.
  • May 1, 2025: Deadline for reporting carbon emissions for the previous year.
  • December 31, 2029: Buildings over 25,000 square feet must meet their emissions limits.
  • May 1, 2030: Deadline for reporting carbon emissions for the previous year.


Carbon Emissions Limits for Buildings under Local Law 97/2019

The carbon emissions limits set by Local Law 97 are based on a building’s occupancy classification and size. Buildings with more people and higher energy use will have stricter emissions limits. The limits are calculated using a formula that takes into account a building’s square footage, occupancy type, and energy use intensity. The limits will become more stringent over time, with the ultimate goal of reducing carbon emissions by 40% by 2030 and 80% by 2050.


Local Law 97 Fines & Calculations

Building owners who fail to comply with Local Law 97 are subject to fines. The fines are calculated based on the amount of carbon emissions that exceed the building’s emissions limits. The penalty for non-compliance is $268 per metric ton of carbon dioxide equivalent emitted above the building’s limit. The penalty can add up quickly, so it’s important for building owners to take the necessary steps to comply with the law.


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Violations for Non-Compliance

Building owners who do not comply with Local Law 97 may face several violations, including:

  • Class 1 violation: Failure to submit an emissions report by the deadline.
  • Class 2 violation: Exceeding the building’s carbon emissions limit by up to 12.5%.
  • Class 3 violation: Exceeding the building’s carbon emissions limit by more than 12.5%.
  • Repeat violations can result in higher penalties and additional enforcement actions.


Local Law 97 Compliance for Building Owners

Building owners can comply with Local Law 97 by taking steps to reduce their building’s carbon emissions. The law provides two pathways for compliance: the prescriptive pathway and the performance pathway.


Prescriptive Pathway

The prescriptive pathway provides a set of measures that building owners can take to reduce their carbon emissions. These measures include upgrading lighting, installing insulation, and upgrading heating and cooling systems. Building owners can choose which measures to implement, but they must meet the required emissions reductions.

The following are measures that building owners can implement to comply with Local Law 97:

  • Upgrade lighting to energy-efficient options such as LED lights.
  • Install insulation to reduce energy loss through walls and roofs.
  • Upgrade heating and cooling systems to more efficient models.
  • Implement building automation systems to optimize energy usage.
  • Install solar panels or other renewable energy systems.
  • Use high-efficiency boilers and chillers.
  • Upgrade windows and doors to reduce air leakage.
  • Use low-flow plumbing fixtures to reduce water usage.
  • Implement green roofs or other sustainable landscaping options.
  • Conduct energy audits to identify areas for improvement.


Article 321 of LL97 requires buildings meet one of the following conditions by 2024 to meet compliance:

  • Annual emissions did not exceed the carbon limits for 2030-2034 (must be a certified report due by May 1, 2025
  • The building implemented the applicable Prescriptive Energy Conservation Measures (ECMs) by December 31, 2024.

A list of Prescriptive Energy Conservation Measures is as follows:

  • Adjust temperature set points for heat and hot water.
  • Repair heating system leaks.
  • Maintain heating system.
  • Install individual temperature controls or insulated radiator enclosures.
  • Insulate heating and hot water pipes.
  • Insulate steam system condensate tank or water tank.
  • Install heating system sensors and boiler controls.
  • Repair or replace steam traps.
  • Install or upgrade steam system master venting.
  • Upgrade common area lighting to comply with New York City Energy Conservation Code.
  • Weatherize and air seal, where appropriate.
  • Install timers on exhaust fans.
  • Install radiant barriers behind all radiators.

These measures can be implemented through the prescriptive pathway of compliance, which provides a set of measures that building owners can take to reduce their carbon emissions.


Performance Pathway

The performance pathway allows building owners to use their own energy efficiency strategies to meet the emissions limits. Building owners must hire a qualified energy consultant to develop an energy model that demonstrates how their building will meet the emissions limits. The energy model must be verified by a qualified independent third party.


EndoTherm as a Suitable Quick Win for Reducing Carbon Emissions

EndoTherm is an additive that can be added to any hydronic heating system to reduce energy consumption and carbon emissions. By optimizing the heat transfer within a heating system, EndoTherm can deliver up to a 15% reduction in space heating energy consumption. This makes it a suitable quick win for building owners who need to reduce their carbon emissions to comply with Local Law 97.

EndoTherm is a low-cost solution that can be installed quickly and easily without the need for major retrofits or equipment replacements. Building owners can install EndoTherm in their heating system and start seeing energy savings immediately. EndoTherm is also compatible with a wide range of heating systems, making it a versatile solution for building owners.

In addition to reducing energy consumption and carbon emissions, EndoTherm can also improve the overall performance of a heating system. By improving the heat transfer within the system, EndoTherm can reduce the time it takes for a building to reach its temperature set points.


Local Law 97 Compliance Advice

Building owners who need assistance with compliance can turn to a variety of resources. The NYC Department of Buildings offers training sessions and technical assistance to help building owners understand the law’s requirements. The NYC Retrofit Accelerator provides free energy efficiency consulting services. Building owners can also work with energy service companies (ESCOs) to identify and implement energy efficiency upgrades.


Local Law 97 Offsets

Building owners can use offsets to comply with Local Law 97. Offsets are a way to reduce carbon emissions outside of a building and can be purchased from qualifying projects. The city has established guidelines for acceptable offset projects, which include renewable energy installations, energy efficiency upgrades, and forest conservation projects.


Reporting Requirements

Building owners must report their building’s carbon emissions to the city annually, using a methodology approved by the NYC Department of Buildings. The emissions report must include data from the previous calendar year and must be submitted by May 1st of the following year.

Building owners who do not submit their emissions report by the deadline will be subject to penalties. There is a penalty for the first month the report is late, and an additional penalty for each additional month the report is late.

The emissions report must also include information on the building’s occupancy classification, size, and energy use intensity. This information will be used to calculate the building’s carbon emissions limits.

Building owners are also required to maintain records of their energy use and emissions data for at least three years. These records may be requested by the city for enforcement purposes.


Local Law 97 of 2019 is a significant step towards reducing carbon emissions in New York City. Building owners who are subject to the law must take action to comply with the emissions limits, or face penalties. Compliance may require significant investments in energy efficiency upgrades, but the city offers resources and incentives to help building owners meet the requirements. By working together to reduce carbon emissions, New York City can lead the way in fighting climate change.


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