Local Law 97 of 2019 — Building Carbon Emissions
LL97 caps the annual carbon emissions of most NYC buildings over 25,000 square feet. The first compliance period (2024–2029) is underway and the first penalties have been billed. The 2030 caps, about 50% stricter, will catch most buildings that cleared 2024.
What Local Law 97 Requires
LL97, the centerpiece of the 2019 Climate Mobilization Act, assigns each covered building an annual emissions limit measured in metric tons of CO2 equivalent per square foot. Buildings that exceed their limit owe $268 per ton over, per year, until they reduce emissions or buy down the gap with allowed offsets.
The caps ratchet down in periods through 2050. The current period runs 2024–2029; the 2030–2034 caps are roughly 50% stricter, and later periods step down toward the law's net-zero target.
Each building's limit depends on its size and property type. Under DOB's December 2023 rules, limits follow the 60 ENERGY STAR Portfolio Manager property types, and mixed-use buildings calculate a weighted average across types.
Article 320 vs Article 321 — which path applies
LL97 splits covered buildings into two compliance pathways. The assignment determines whether you face annual emissions caps with per-ton penalties or a one-time prescriptive checklist with flat penalties.
Article 320
Article 320 covers most private buildings: market-rate residential, commercial, mixed-use, and any building with 35% or fewer rent-regulated units. If your building doesn't qualify for Article 321, it's an Article 320 building.
Article 320 buildings:
- Submit annual emissions reports by May 1 each year
- Must meet their assigned emissions cap each year
- Owe $268 per metric ton over the cap, per year
- Owe $0.50 per square foot per month for failure to file
- Can apply offsets, RECs, and electrification credits to reduce their reported emissions
Article 321
Three categories qualify for the prescriptive pathway:
- Affordable housing where more than 35% of units are rent-regulated
- Houses of worship and other A-3 occupancy religious buildings
- HDFC co-ops and certain other income-restricted buildings
Two compliance options, both one-time:
- Prescriptive Energy Conservation Measures (PECMs) — implement a defined list of low-cost energy upgrades and submit a one-time report certified by a qualified retro-commissioning agent.
- Performance pathway — demonstrate that the building's 2024 emissions already meet the 2030 limit, and submit a one-time report certified by an RDP.
A 2020 amendment lowered the Article 321 rent-regulated threshold to 35%, moving buildings with 1–34% rent-regulated units to Article 320 starting in 2026. Some buildings that planned for one-time PECMs now face annual caps.
The DOB Covered Buildings List indicates each building's assigned pathway, and assignments can be challenged through DOB.
Deadlines and the compliance period structure
Reports are due May 1 each year, covering the prior calendar year, with late-filing penalties accruing from May 2. In the first cycle DOB also published a grace period and an extension window; check the current year's notice on the DOB LL97 page for what applies now.
The 2026 cycle matters most for buildings on the Good Faith Effort (GFE) Decarbonization Plan pathway, the penalty mitigation structure that gave first-period buildings room to plan rather than face immediate cap penalties. GFE buildings have two checkpoints:
- May 1, 2026: complete all work necessary to meet the 2024–2029 emissions limit
- May 1, 2028: have approved DOB work plans in place to meet the 2030–2034 limit
GFE buildings that haven't executed against their commitments (retrofits, electrification, lighting upgrades, envelope work) risk losing GFE protection and being penalized retroactively for 2024 and 2025.
The 2030 caps are the real deadline. They are roughly 50% stricter than the current period, and industry estimates suggest most currently covered buildings would exceed them at current performance. The work to comply has to be planned, financed, and largely executed during this period.
Penalties
Per-ton penalties have no annual cap, which is what makes LL97 the expensive one in the cluster.
Article 320 penalties
Article 321 penalties
What This Looks Like in Practice
A 250,000-square-foot office building that exceeds its 2024 cap by 200 metric tons CO2e owes $53,600 for that year. At the same emissions level in 2030, when the cap is roughly half, the overage doubles to about 400 tons and the annual penalty to $107,200.
Failure to file is its own exposure: $0.50 per square foot per month is $50,000 a month on a 100,000-square-foot building. The first round of penalty billing has happened; buildings whose 2024 reports showed an exceedance are receiving bills. Figures reflect DOB's published schedule, checked July 2026.
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Compliance flexibility — RECs, electrification credits, AHRF
DOB has built flexibility mechanisms into LL97. None replaces actual reduction, but they change the math for buildings that plan ahead.
Beneficial Electrification (BE) Credit. Buildings that replace fossil fuel heating, cooling, or hot water with qualifying high-efficiency electric equipment earn credits against their limits, with double credits for equipment installed through 2026 and none after 2030. The credit applies automatically in the filing.
Renewable Energy Credits (RECs). Article 320 buildings can use qualifying RECs to offset excess electricity emissions during 2024–2029. Qualifying RECs are limited to Tier 4 projects delivering renewable power into NYC, a short list as of mid-2026. Buildings on the GFE Decarbonization Plan pathway cannot use RECs during the first compliance period.
Affordable Housing Reinvestment Fund (AHRF) Offsets. Article 320 buildings can purchase offsets at $268 per ton, funding electrification in qualifying affordable housing, capped at 10% of the building's annual limit.
Onsite renewables and storage. Rooftop solar, storage, and other distributed energy resources can also reduce a building's reported emissions.
Common Pitfalls
Assuming Article 321 status without verifying the rent-regulated percentage.
The 2020 amendment lowered the threshold to 35%, so buildings that assumed they qualified for the prescriptive path may now sit under Article 320. Verify against the DOB Covered Buildings List before planning a compliance strategy.
Banking on RECs while on a Decarbonization Plan.
Buildings on the GFE Decarbonization Plan pathway are prohibited from using RECs during 2024–2029; owners who chose GFE to defer penalties can't then buy RECs instead of decarbonizing. Confirm your pathway before assuming RECs will close a compliance gap.
Mixed-use limit calculation done wrong.
A building with retail, office, and residential portions calculates its limit as a weighted average across the relevant property types. Wrong property-type assignments produce a wrong limit, so mixed-use buildings should have the calculation verified by an RDP rather than estimated from a generic occupancy class.
How LuxNet Helps with LL97
We don't replace an LL97 emissions consultant or RDP. We supply the building data their model depends on: fixture inventories, controls documentation, retrofit scope, and the LL88 overlap. LL97 plans built on unverified spreadsheet assumptions surface the errors later as scope changes and rework; field-verified inputs make the model credible to the RDP signing it and the board reviewing the capital plan.
The same survey that produces an LL88 attestation produces the lighting and controls baseline an LL97 plan needs, and our controls design and commissioning work feeds the building-side commitments a GFE plan has to make. A scoping call settles where that fits alongside your emissions consultant.
Is my building covered by Article 320 or Article 321?
How is my emissions limit calculated?
What's the penalty per ton over the limit?
Do I have to file every year?
What happens in 2030?
What happens to the caps after 2034?
Can I use renewable energy credits to comply?
What's the Beneficial Electrification Credit?
Clearing 2024 Doesn't Mean Clearing 2030.
The 2030 caps tighten by roughly half, and most currently covered buildings would exceed them at today's performance. The work to get under has to be scoped, financed, and largely executed during this compliance period. Start with a building check; we'll scope where field-verified data fits in your LL97 plan.
Penalty figures and compliance details reflect DOB's published rules and can change. This page is general information, not legal or financial advice; confirm specifics with DOB, your utility, and your own professionals.
Last updated: July 2026. NYC building compliance rules, deadlines, and DOB procedures may change.