Local Law 97 NYC Explained: Building Emissions Compliance Guide 2025

NYC Local Law 97 (LL97) is the most ambitious building emissions law in the United States, requiring most buildings over 25,000 square feet to meet strict carbon emissions limits starting in 2024. Non-compliance can result in penalties of $268 per ton of CO2 equivalent over the limit annually, potentially costing building owners hundreds of thousands or even millions of dollars per year. This comprehensive guide explains everything building owners, boards, and property managers need to know about Local Law 97 compliance.

What is Local Law 97?

Local Law 97, part of NYC's Climate Mobilization Act passed in 2019, sets carbon emissions limits for buildings over 25,000 sq ft. It's the cornerstone of NYC's plan to reduce greenhouse gas emissions 80% by 2050.

Key Facts:

Effective: January 1, 2024 (first compliance period)
Covers: ~50,000 buildings (75% of NYC's built square footage)
Threshold: Buildings 25,000+ sq ft (or multiple buildings on same tax lot totaling 50,000+ sq ft)
Penalty: $268/ton CO2e over annual limit
Enforcement: NYC Department of Buildings (DOB)

Buildings Covered by Local Law 97

Covered Buildings:

Buildings over 25,000 gross sq ft
Two or more buildings on same tax lot totaling 50,000+ sq ft
Two or more condominium buildings governed by same board totaling 50,000+ sq ft

Exempt Buildings:

Real property owned by city, state, or federal government
Houses of worship
Rent-regulated buildings where 35%+ units are occupied by tenants with household income ≤60% AMI (can get penalties waived)
Industrial facilities with direct access to rail or maritime transportation
Buildings with temporary certificates of occupancy

Emissions Limits and Compliance Periods

LL97 sets emissions limits in kg CO2e per square foot per year that decrease over time:

Compliance Period 1: 2024-2029

Limits based on building occupancy type. Examples:

Building Type	Limit (kg CO2e/sq ft/yr)
Multifamily Housing	0.00568
Office	0.00533
Hotel	0.00482
Retail/Commercial	0.00471
Hospital	0.00907

Compliance Period 2: 2030-2034

Limits reduced by approximately 20-30% from 2024 levels. Buildings must achieve deeper emissions reductions.

Post-2035

Further reductions to align with NYC's goal of carbon neutrality by 2050.

How Emissions Are Calculated

Building emissions calculated using:

Energy Use Data:

Electricity: kWh consumed × grid emissions factor
Natural gas: therms consumed × gas emissions factor
Steam: mlbs consumed × steam emissions factor
Fuel oil: gallons consumed × oil emissions factor

Emissions Factors (2024):

Electricity (grid): 0.000288962 tCO2e/kWh
Natural gas: 0.00531 tCO2e/therm
Steam: 0.0385 tCO2e/mlb
Fuel oil #2: 10.21 kg CO2e/gallon

Formula:
Annual Building Emissions (kg CO2e) ÷ Gross Floor Area (sq ft) = kg CO2e/sq ft/yr

If this number exceeds your building's limit, you owe penalties on the excess.

Penalties for Non-Compliance

Penalty Rate: $268 per metric ton of CO2 equivalent over the limit (indexed for inflation)

Example Penalty Calculation:

Scenario: 100,000 sq ft multifamily building

Emissions Limit: 0.00568 kg CO2e/sq ft/yr = 568,000 kg (568 metric tons)
Actual Emissions: 0.00700 kg CO2e/sq ft/yr = 700,000 kg (700 metric tons)
Excess: 132 metric tons
Annual Penalty: 132 tons × $268 = $35,376

Penalties assessed annually for each year building exceeds limit. Large buildings can face penalties in the hundreds of thousands or millions of dollars.

Compliance Strategies

1. Energy Efficiency Upgrades

HVAC modernization: High-efficiency boilers, chillers, heat pumps
Building envelope: Insulation, air sealing, window replacement
Lighting: LED conversion with controls
Controls & automation: Building management systems, smart thermostats
Hot water: Heat pump water heaters, solar thermal

2. Fuel Switching

Replace gas/oil boilers with electric heat pumps
Electrify domestic hot water
Switch from steam to electricity where possible

3. On-Site Renewable Energy

Rooftop solar PV systems
Building-integrated solar (facades, canopies)
On-site wind (rare in NYC but possible)

4. Purchase Renewable Energy Credits (RECs)

Buy RECs to offset up to 10% of emissions in 2024-2029 (5% in 2030+). Not a permanent solution but can help in transition.

5. Request Adjustments

Apply for emissions limit adjustments for:

Prescribed greenhouse gas intensities (specific occupancy types)
Buildings with high energy needs (data centers, labs, etc.)
Eligible affordable housing (penalties waived, not limits adjusted)

Reporting Requirements

Annual Reporting (May 1 deadline):

Report building emissions through DOB's online portal
Based on previous calendar year energy consumption
Must use certified energy data from utility bills or benchmarking
Signed by registered design professional (RDP) or qualified person

Documentation Required:

12 months of utility bills
Building square footage calculations
Occupancy classifications
REC purchases (if applicable)
Any adjustment applications

Failure to report: $0.50 per sq ft penalty (minimum $1,250) × each month late

Available Incentives and Financing

NYC Accelerator

Free technical assistance and resources to help buildings comply with LL97. Services include:

Energy audits and retrofit planning
Financing guidance
Vendor connections

Website: accelerator.nyc

NYSERDA Programs

FlexTech: Up to 50% cost share for energy studies
MPP (Multifamily Performance Program): Incentives for efficiency upgrades
Real Time Energy Management: Free building management systems

Con Edison Rebates

HVAC equipment rebates
Lighting rebates
Custom incentives for large projects

PACE Financing

Property Assessed Clean Energy loans for efficiency upgrades, repaid through property tax bills.

Getting Started with LL97 Compliance

Step 1: Determine if Building is Covered

Calculate gross square footage including all floors (except parking). Check if building meets 25,000 sq ft threshold.

Step 2: Calculate Current Emissions

Gather 12 months of utility bills. Use DOB's calculator or hire energy consultant to calculate emissions intensity.

Step 3: Compare to Limit

Find your building's emissions limit based on occupancy classification. Calculate gap between current emissions and limit.

Step 4: Develop Compliance Plan

Options:

Hire energy consultant for comprehensive audit
Contact NYC Accelerator for free assistance
Get quotes from contractors for priority upgrades
Explore financing options

Step 5: Implement Projects

Prioritize upgrades with best ROI and emissions reduction. Many buildings need multi-year capital plans to achieve compliance.

Step 6: File Annual Reports

Report emissions by May 1 annually through DOB portal. Track progress toward compliance.

Frequently Asked Questions

When do penalties start?

Penalties for excess emissions begin January 1, 2025 for the 2024 compliance year. First reports due May 1, 2025.

Can I pay penalties instead of reducing emissions?

Legally yes, but penalties are recurring annually and expensive. Most buildings find compliance upgrades more cost-effective long-term.

What if I'm planning a major renovation?

Coordinate with LL97 compliance. Major renovations are opportunity to integrate emissions reduction measures.

Are there exemptions for historic buildings?

No automatic exemption. However, can apply for emissions limit adjustment if landmark restrictions prevent certain upgrades.

How is LL97 enforced?

DOB enforces through annual reporting system. Non-reporting or excess emissions trigger automatic penalties. Can result in building liens if unpaid.

Related Resources

External Resources

Last updated: November 2025. This guide is for informational purposes only and does not constitute legal or engineering advice. Consult licensed professionals for LL97 compliance planning.