What Is NYC Local Law 97? A Building Owner's Complete Guide

What Is Local Law 97?

New York City Local Law 97 of 2019 — part of the NYC Climate Mobilization Act — establishes annual greenhouse gas (GHG) emissions caps for most buildings larger than 25,000 square feet. It is the most ambitious building decarbonization law in the United States.

Buildings that exceed their assigned emissions cap are fined $268 per metric ton of CO₂e above the limit per year. For large buildings, that can mean hundreds of thousands of dollars in annual penalties if no action is taken.

Who Is Subject to LL97?

Most privately owned buildings with more than 25,000 square feet of gross floor area (GFA) are covered. This also applies to:

• Two or more buildings on the same tax lot totaling over 50,000 sq ft combined
• Condominiums where individual unit tax lots collectively exceed 25,000 sq ft

Exemptions include certain houses of worship, rent-regulated affordable housing (under specific programs), and some NYC HPD-managed properties.

How Is the Emissions Cap Calculated?

Each building receives an annual emissions cap based on two factors:

1. Occupancy type — the primary and secondary use types reported in ENERGY STAR Portfolio Manager (e.g., office, multifamily residential, retail, parking)
2. Gross Floor Area (GFA) — the total enclosed building area in square feet

The formula is: Cap = emissions_limit_per_sq_ft × GFA

The emissions limit per square foot varies by occupancy type. Mixed-use buildings calculate a blended cap across all use types proportionally.

Compliance Periods

LL97 is structured in phases of progressively stricter limits:

• Phase 1 (2024–2029): Initial limits. Many buildings are already at risk of fines.
• Phase 2 (2030–2034): Significantly tighter limits. Most buildings will require mechanical upgrades or fuel switching to comply.
• Phase 3 (2035–2049): Further tightening toward net-zero.
• Phase 4 (2050): Net-zero emissions goal for all covered buildings.

How Is Compliance Measured?

The NYC Department of Buildings uses the total GHG emissions figure from your Local Law 84 annual benchmarking filing — submitted through ENERGY STAR Portfolio Manager — to determine your LL97 compliance status each year.

Total GHG emissions include:

• Direct emissions (Scope 1): On-site combustion of natural gas, fuel oil, and other fossil fuels
• Indirect emissions (Scope 2): Purchased electricity and district steam, converted using grid and steam supplier emission factors

What Happens If You Exceed the Cap?

For each year in which your building's reported GHG emissions exceed its LL97 cap, the NYC Department of Buildings issues a fine equal to:

Fine = (Actual Emissions − Annual Cap) × $268

There is no grace period for Phase 1. Buildings that exceeded their 2024 cap received a violation in 2025. Fines are issued annually and can compound year over year.

How to Reduce LL97 Exposure

The most reliable path to compliance is reducing actual GHG emissions through building upgrades:

• HVAC system replacements (heat pumps, high-efficiency boilers)
• Building envelope improvements (insulation, window upgrades)
• Lighting retrofits and controls
• Electrification of heating systems
• Tenant metering and sub-metering to identify usage drivers

Limited alternative compliance pathways also exist, including purchasing renewable energy credits (RECs) under specific rules, and Article 320/321 adjustments for buildings with specific constraints.

How EnergiDash Helps

EnergiDash calculates your building's LL97 fine exposure for both Phase 1 and Phase 2 periods using your live ENERGY STAR Portfolio Manager data — no spreadsheet exports required. You can see your current exposure, compare it across your entire portfolio, and identify which buildings require the most urgent attention before the annual filing deadline.