Local Law 97 is New York City's law limiting greenhouse gas emissions from large buildings. The first compliance period started in 2024 and runs through 2029. In 2030 the limits drop sharply, and many buildings that comply today will not. This guide explains what changes and how to estimate your exposure.
Which buildings are covered
LL97 applies to most buildings over 25,000 gross square feet, and to groups of buildings on one tax lot, or in one condominium, that together exceed 50,000 square feet. Some building types, including rent-regulated housing and certain houses of worship, follow alternative compliance paths.
How your limit is calculated
Each occupancy group has an emissions intensity limit in metric tons of CO₂e per square foot. Your annual limit is that intensity multiplied by your gross floor area. Mixed-use buildings add up the limit for each occupancy group's floor area.
| Occupancy group | 2024–2029 | 2030–2034 | Change |
|---|---|---|---|
| B · Office | 8.46 | 4.53 | −46% |
| R-2 · Multifamily | 6.75 | 4.07 | −40% |
| R-1 · Hotel | 9.87 | 5.26 | −47% |
| M · Retail | 11.81 | 4.03 | −66% |
| E · School | 7.58 | 3.44 | −55% |
| S · Storage | 4.26 | 1.10 | −74% |
Limits in kgCO₂e per square foot per year.
How your emissions are calculated
Annual use of each energy source is multiplied by a greenhouse gas coefficient. For 2024–2029, grid electricity is 0.000288962 tCO₂e per kWh and natural gas is 0.00005311 tCO₂e per kBtu. District steam and fuel oils have their own coefficients. The city may set different coefficients for 2030 and later, which is one reason to revisit your estimate as rules are updated.
A worked example
Take a 100,000 sq ft office using 2.1 million kWh of electricity and 62,000 therms of gas a year. Electricity produces about 607 tCO₂e and gas about 329 tCO₂e, for roughly 936 tCO₂e in total.
- 2024–2029 limit: 100,000 × 8.46 kg = 846 tCO₂e. The building is about 90 tons over, roughly $24,000 a year in penalties.
- 2030–2034 limit: 100,000 × 4.53 kg = 453 tCO₂e. The building is about 483 tons over, roughly $129,000 a year.
What to do now
- Calculate your position for both periods. Our LL97 calculator gives a quick estimate.
- Get an ASHRAE Level II audit. It identifies the measures that cut emissions at the lowest cost. If your LL87 report is due, the same audit can serve both purposes.
- Plan by equipment age. Time boiler replacements, heat pump conversions and major controls upgrades to happen before 2030 rather than in a rush.
- Capture incentives. Con Edison, NYSERDA and city programs fund much of the cost of efficiency and electrification projects.
Want a building-specific plan? Contact our engineers or start with a free energy screening.