NYC Local Law 97 Carbon Penalty & Retrofit ROI Modeler
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Annual penalty by compliance period
| Period | Limit (tCO₂e) | Emissions now | Penalty now | Emissions after retrofit | Penalty after |
|---|
How the modeler calculates
- Emissions = energy use × LL97 coefficients. 2024–2029: grid electricity 0.000288962 tCO₂e/kWh, natural gas 0.00005311, No. 2 oil 0.00007421 and district steam 0.00004493 tCO₂e/kBtu. 2030–2034: electricity 0.000145 and steam 0.0000432, with fuels unchanged. Coefficients after 2034 are not yet set, so the 2030–2034 values are held constant.
- Limit = gross floor area × the emissions factor for the property type in 1 RCNY §103-14 for each period.
- Penalty = (emissions − limit) × $268 for each year over the limit.
- Retrofit savings apply in order: retro-commissioning, LED, envelope, then heat pumps. Heat pumps replace 70% of the remaining fuel and steam with electricity at the COP you set.
- Payback = net capex after incentives ÷ (energy cost saved + 2030–2034 penalty avoided).
This is a screening estimate, not a compliance filing. Reports must be certified by a registered design professional, and deductions such as RECs, offsets (capped at 10% of the limit) or adjustments can change the result. Limits and coefficients from 1 RCNY §103-14 and NYC DOB guidance, checked October 2026.
Related guides and tools
Frequently asked questions
How much is the Local Law 97 penalty?
The penalty is $268 for every metric tonne of CO2e a covered building emits above its annual limit, for each calendar year it is over. Separately, failing to file the annual report costs $0.50 per gross square foot for each month the report is late, within the 12 months after the May 1 deadline.
Why do LL97 limits get so much stricter in 2030?
The law targets a 40% cut in emissions from large buildings by 2030 and net zero by 2050. For 2030 to 2034 the per-square-foot limits for most property types fall by 50% to 80% compared with 2024 to 2029. The electricity coefficient also halves, from 0.000288962 to 0.000145 tCO2e per kWh, which rewards buildings that electrify heating.
When are Local Law 97 reports due?
Reports for each calendar year are due on May 1 of the following year, with a 60-day grace period to June 30, and owners can apply for an extension to August 29. The first reports, covering 2024, were due on December 31, 2025. Reports for 2025 were due on May 1, 2026.
How accurate is this Local Law 97 calculator?
It uses the official LL97 emissions factors by property type and the statutory carbon coefficients, so the arithmetic matches the law for a single-use building. Results depend on your energy inputs and the retrofit assumptions, which are illustrative. Mixed-use buildings, deductions, RECs, offsets and adjustments are not modelled, and filings must be certified by a registered design professional.
Can carbon offsets or RECs be used for LL97 compliance?
Partly. The only eligible offsets are certificates from the city's Affordable Housing Reinvestment Fund, priced at $268 per tonne and capped at 10% of a building's emissions limit. Renewable energy certificates that meet DOB's LL97 REC policy can be deducted against grid electricity emissions. Neither replaces the need to cut on-site fossil fuel use over time.