What Is Local Law 97?

Local Law 97: The Definition

Local Law 97 (LL97) is the centerpiece of NYC's Climate Mobilization Act, signed in 2019. It sets carbon emissions caps on buildings over 25,000 square feet — roughly 50,000 buildings citywide — with the goal of reducing building emissions 40% by 2030 and 80% by 2050 versus 2005 levels.

LL97 is enforced by the NYC Department of Buildings' Bureau of Sustainability. Owners of covered buildings must report annual emissions and pay penalties on any tons above the cap. The first compliance period is 2024–2029, with tighter caps kicking in for 2030–2034.

LL97 is a real, active penalty regime. If your building is over 25,000 sq ft, LL97 applies. If you're not sure where you stand, our property analysis service can determine your exposure.

The LL97 Compliance Timeline

Which Buildings Are Covered?

LL97 applies to most buildings over 25,000 square feet — and, in aggregate, to two or more buildings on the same tax lot totaling over 50,000 sq ft, or two or more condo buildings governed by the same board totaling over 50,000 sq ft.

Specific carve-outs (partial or full) apply to certain building types:

• Buildings with rent-regulated units — Article 321 alternative compliance path is available
• NYCHA-owned buildings — separate compliance path
• Houses of worship — limited exemption
• Industrial buildings used primarily for industrial processes — partial exemption
• Certain landmarked buildings — some flexibility depending on retrofit constraints

LL97 penalties are tied directly to how many metric tons of CO₂-equivalent your building emitted above the cap:

Paths to LL97 Compliance

Compliance strategies vary based on building type, existing systems, and capital availability. Common approaches include:

• Efficiency retrofits — LED lighting, HVAC upgrades, controls optimization, and envelope improvements can produce 10–25% emissions reductions.
• Fuel switching / electrification — Replacing gas-fired heating with heat pumps eliminates on-site combustion emissions. Typically Period 2 (2030+) compliance.
• Beneficial electrification credits — Buildings that add heat pumps or eliminate fossil equipment can earn credit against their emissions cap.
• Green power purchases (limited use) — Certain renewable energy credits count against the cap, with restrictions on how many can be used.
• Good faith efforts adjustment — For buildings in Period 1 that demonstrate genuine effort but face structural obstacles, adjustments may reduce or defer penalties.
• Article 321 alternative path (rent-regulated) — Buildings with rent-regulated units can pursue a prescriptive measures pathway instead of the emissions cap approach.

The annual LL97 filing is due each May 1 covering the prior calendar year. The report must be prepared by a registered design professional (PE or RA) and includes:

• Total annual greenhouse gas emissions by fuel source
• Emissions intensity calculation (tons CO₂e per sq ft)
• Applicable emissions limit based on occupancy group
• Any deductions (beneficial electrification, RECs, etc.)
• Certifying professional's signature and license number

LL97 works alongside other NYC building energy laws including Local Law 84 (energy benchmarking), Local Law 87 (energy audits), and Local Law 88 (lighting and sub-metering upgrades). Compliance strategy should account for all four — the same efficiency retrofits often satisfy multiple laws.