How to Calculate Your Building’s Carbon Limit Under Local Law 97
New York City’s Local Law 97 (LL97) is one of the most ambitious climate laws in the United States. It was created as part of the Climate Mobilization Act to reduce greenhouse gas emissions from buildings, which account for nearly 70 percent of New York City’s total emissions.
For building owners and property managers, understanding how to calculate a building’s carbon limit under Local Law 97 is essential for avoiding penalties and planning long-term energy improvements. The law applies primarily to buildings larger than 25,000 square feet and establishes strict carbon emission limits that become progressively tighter over time.
If you own or manage a building in New York City, calculating your building’s carbon limit is the first step toward compliance.
Understanding Local Law 97 Carbon Limits
Local Law 97 sets annual carbon emission limits for covered buildings. These limits are based on two main factors:
- The building’s occupancy group
- The building’s gross floor area
Each occupancy category—such as residential, office, hotel, or retail—has a specific emissions intensity limit measured in metric tons of carbon dioxide equivalent (tCO2e) per square foot.
To determine the allowed emissions for your property, you multiply the emissions limit for your building type by the total floor area of the building.
This calculation determines the maximum carbon emissions your building can produce in a given year without facing penalties.
The limits are stricter in future compliance periods, which means buildings that meet today’s requirements may still need upgrades in the coming years.
Step 1: Determine if Your Building Is Covered
Before calculating carbon limits, building owners must confirm whether their property is subject to Local Law 97 compliance.
The law generally applies to:
- Buildings larger than 25,000 square feet
- Multiple buildings on the same tax lot exceeding 50,000 square feet
- Condominiums governed by a single board with combined floor areas over 50,000 square feet
Some buildings are exempt, including houses of worship, certain industrial facilities, and properties with limited energy usage.
Most commercial buildings, residential towers, and mixed-use properties in New York City fall under LL97 requirements.
Step 2: Identify the Building Occupancy Group
The next step is determining your building’s occupancy classification. This classification is based on the NYC Department of Buildings categories and helps define the emissions intensity limit applied to the building.
Common occupancy groups include:
- Multifamily residential buildings
- Office buildings
- Hotels
- Retail buildings
- Educational facilities
- Healthcare facilities
Each group has a different carbon emissions limit because different building types consume energy differently.
For example, residential buildings generally have lower emissions limits compared to commercial office buildings because their energy consumption patterns differ.
Mixed-use buildings must calculate carbon limits separately for each occupancy group and then combine them to determine the building’s total emissions limit.
Also Read: LL97 Compliance for Hotels and Hospitality Buildings
Step 3: Find the Emissions Intensity Limit
Once the building occupancy group is identified, you must locate the emissions intensity limit for the applicable compliance period.
Local Law 97 currently defines two primary compliance periods:
2024–2029 compliance period
2030–2034 compliance period
The emissions limits become significantly stricter after 2030.
For example, a multifamily residential building might have a carbon limit around 0.00675 tCO2e per square foot during the first compliance period. In later years, the allowed emissions decrease, requiring greater energy efficiency.
These limits are designed to gradually reduce carbon emissions across New York City’s building stock.
Step 4: Calculate the Building’s Carbon Limit
After identifying the emissions intensity limit and confirming the building’s total square footage, the carbon limit can be calculated using a simple formula.
Carbon Limit = Building Floor Area × Emissions Limit
For example:
If a residential building has 100,000 square feet of floor area and the emissions intensity limit is 0.00675 tCO2e per square foot, the calculation would be:
100,000 × 0.00675 = 675 metric tons of carbon dioxide equivalent per year.
This means the building cannot exceed 675 tCO2e annually during that compliance period.
If the building’s emissions exceed the limit, the owner may face financial penalties.
Step 5: Calculate Your Building’s Actual Carbon Emissions
To determine whether your building complies with Local Law 97, you must calculate its actual carbon emissions.
Actual emissions are determined using the building’s energy consumption data from sources such as:
- Electricity usage
- Natural gas consumption
- Fuel oil usage
- District steam
- Other energy sources
Each energy source has a specific emissions factor used to convert energy usage into carbon emissions.
For example, electricity consumption is converted into carbon emissions using a factor that reflects the emissions associated with electricity generation.
The general formula is:
Energy Usage × Emissions Factor = Carbon Emissions
After calculating emissions for each energy source, they are added together to determine the building’s total annual emissions.
Step 6: Compare Actual Emissions With the Carbon Limit
Once both numbers are available—the building’s carbon limit and its actual emissions—the final step is to compare them.
If actual emissions are below the limit, the building complies with Local Law 97.
If emissions exceed the allowed limit, the building will face annual penalties. The penalty is currently set at approximately $268 per metric ton of carbon emissions above the limit.
For large buildings, these penalties can quickly become significant.
As a result, many building owners are investing in energy efficiency upgrades to reduce emissions and avoid long-term compliance costs.
Strategies to Reduce Carbon Emissions
If your building exceeds its Local Law 97 emissions limit, several strategies can help reduce carbon output.
Energy efficiency improvements are often the most effective approach.
Common solutions include upgrading HVAC systems, improving insulation, installing energy-efficient lighting, and implementing smart building controls.
Building retrofits and energy audits can also identify hidden inefficiencies that contribute to excessive energy consumption.
Renewable energy sources, such as solar panels, can further reduce a building’s carbon footprint.
Many building owners also pursue retro-commissioning projects to ensure that building systems operate as efficiently as possible.
These strategies not only support LL97 compliance but can also reduce long-term operating costs.
The Role of Energy Audits in Local Law 97 Compliance
Energy audits play a critical role in helping building owners understand how energy is used within their properties.
An energy audit evaluates major systems such as heating, cooling, lighting, and ventilation to identify opportunities for energy savings.
Audits often reveal inefficiencies that significantly contribute to high carbon emissions.
By implementing the recommended upgrades from an energy audit, building owners can reduce energy consumption and move closer to meeting Local Law 97 emissions targets.
Energy audits are also closely connected to other NYC building compliance requirements, including Local Law 87.
Planning Ahead for Future Compliance Periods
Many buildings that meet the emissions limits for the 2024–2029 period may struggle to comply with the much stricter limits starting in 2030.
This makes long-term planning essential.
Building owners should evaluate their energy performance now and develop a roadmap for improvements that will ensure future compliance.
Waiting until penalties occur can result in higher costs and rushed upgrades.
Early planning allows building owners to schedule improvements strategically and take advantage of available incentives or energy efficiency programs.
Why Professional Guidance Matters
Calculating and managing carbon emissions under Local Law 97 can be complex, particularly for large or mixed-use buildings.
Compliance requires accurate data analysis, emissions calculations, and long-term energy planning.
Working with experienced building compliance professionals can help property owners understand their current emissions profile and identify practical solutions to reduce carbon output.
Professional consultants can also help prepare required documentation, verify emissions calculations, and guide building owners through the compliance process.
Conclusion
Local Law 97 represents a major shift in how buildings in New York City manage energy consumption and carbon emissions.
For building owners, understanding how to calculate a building’s carbon limit is the foundation of compliance. By determining the building’s occupancy group, identifying emissions intensity limits, calculating allowable emissions, and comparing them with actual energy usage, property owners can clearly understand their compliance status.
With stricter limits approaching in the coming years, proactive planning and energy efficiency improvements are critical.
Building owners who start preparing today will be better positioned to avoid penalties, improve building performance, and contribute to New York City’s long-term climate goals.
