Local Law 97 Compliance Retrofit Planner
New York City’s Local Law 97 (LL97) sets carbon-emissions caps for most large buildings. This planner helps you translate those caps into estimated emissions, compliance margins, potential penalties, and simple payback for retrofit investments. It is designed for owners, managers, and consultants who already have basic energy and emissions data and want a quick, scenario-based view of how retrofits and renewable energy credits could affect LL97 exposure.
How this Local Law 97 planner works
The calculator combines your building’s size, current emissions intensity, target limit, energy use, and retrofit assumptions to estimate:
- Baseline annual emissions from electricity and fuel use
- Post-retrofit emissions after projected savings and renewable energy credits
- Compliance margin relative to your selected LL97 target intensity
- Indicative penalty exposure based on a penalty rate per metric ton of CO₂e
- Simple payback period for your capital investment, using energy and maintenance savings
You supply the emissions factors, cost assumptions, and penalty rate so you can align the planner with the latest LL97 guidance and your building’s specific situation.
Key formulas used in the planner
At a high level, the tool uses standard energy and emissions accounting. Conceptually, the main steps are:
- Baseline emissions intensity: your current emissions per square foot, in kgCO₂e/sq ft.
- Allowed emissions intensity: the LL97 limit you enter for your building type and compliance year, also in kgCO₂e/sq ft.
- Total emissions: emissions intensity multiplied by gross floor area.
- Compliance margin: the difference between actual emissions and the LL97 cap.
For example, baseline whole-building emissions (in metric tons of CO₂e) can be expressed as:
The division by 1,000 converts kilograms of CO₂e into metric tons of CO₂e (tCO₂e).
Similarly, an annual LL97 emissions cap (in tCO₂e) is:
The compliance margin is then:
Compliance margin (tCO₂e) = Post-retrofit emissions − Emissions cap
If the margin is positive, the building is above the cap and may be subject to penalties. A negative margin indicates a buffer below the cap.
Inputs explained
To get realistic estimates, use data from recent benchmarking reports, energy audits, or your LL97 consultant. In particular:
- Gross Floor Area (sq ft): total area covered by LL97 reporting, typically matching your annual benchmarking submission. Verify the definition with NYC Department of Buildings (DOB) guidance.
- Baseline Emissions Intensity: your current emissions per square foot. Many users start with the intensity implied by their most recent LL97 or benchmarking filing.
- Target Limit Intensity: the LL97 limit (kgCO₂e/sq ft) for your building’s occupancy group and compliance period. This value comes from the law and official rulemaking, not from the tool.
- Annual Electricity Use and Fuel Use: kWh and therms from utility bills or submetering, for a typical year.
- Emissions factors: kgCO₂e/kWh and kgCO₂e/therm that match the LL97 rules or your internal planning assumptions for the chosen compliance year.
- Energy rates and maintenance savings: rough average prices and annual savings based on your utility tariffs, service contracts, and retrofit proposals.
- Renewable Energy Credits (RECs): kWh of qualifying renewable purchases you plan to apply toward LL97 compliance, if allowed under the latest rules.
- Penalty rate ($/tCO₂e): an indicative rate per metric ton of CO₂e above the cap, based on Local Law 97 and subsequent rulemaking. The planner simply multiplies this by your estimated exceedance.
Interpreting your results
Once you enter your data and run the calculation, focus on a few headline outputs:
- Baseline emissions: your current annual emissions before any new retrofits or RECs.
- Post-retrofit emissions: estimated emissions after applying projected savings and renewable purchases.
- Compliance margin: shows how far above or below the LL97 cap you may be.
- Estimated annual penalty: your potential exposure in a representative year if emissions remain unchanged and the penalty rate applies as entered.
- Simple payback: years required for cumulative annual savings (energy plus maintenance) to equal the capital investment, ignoring financing and escalation.
Positive vs. negative compliance margin:
- A positive
- A negative
Use the penalty estimate as a planning signal rather than an official bill. Actual LL97 compliance depends on detailed rules, verified data, and DOB determinations.
Worked example (illustrative only)
Consider a hypothetical 100,000 sq ft multifamily building:
- Baseline emissions intensity: 12 kgCO₂e/sq ft
- Target intensity (LL97 limit for the period): 8 kgCO₂e/sq ft
- Annual electricity: 1,200,000 kWh; factor: 0.00025 kgCO₂e/kWh
- Annual fuel: 80,000 therms; factor: 5.0 kgCO₂e/therm
- Planned retrofit savings: 200,000 kWh and 20,000 therms
- Penalty rate: $268/tCO₂e (example figure)
- Capital cost: $2,500,000; annual maintenance savings: $50,000
Baseline emissions using intensity only:
Baseline emissions = 12 × 100,000 ÷ 1,000 = 1,200 tCO₂e/year
Cap using target intensity:
Emissions cap = 8 × 100,000 ÷ 1,000 = 800 tCO₂e/year
The building is 400 tCO₂e above the cap before retrofits. With the sample penalty rate, that implies:
Indicative annual penalty = 400 × $268 ≈ $107,200
If retrofit savings reduce emissions intensity enough to bring post-retrofit emissions down to the cap (800 tCO₂e), the compliance margin becomes zero and the modelled penalty drops to roughly $0. Assuming combined annual energy and maintenance savings of $300,000:
Simple payback = $2,500,000 ÷ $300,000 ≈ 8.3 years
Your own results will differ, but this illustrates how the planner links emissions, penalties, and investment decisions into one view.
Comparison of baseline vs. retrofit scenario
The table below shows the kinds of numbers you might compare before and after a retrofit scenario. Actual values will be generated by your inputs to the calculator.
| Metric | Baseline scenario | Post-retrofit scenario |
|---|---|---|
| Total annual emissions (tCO₂e) | Higher; may exceed LL97 cap | Lower; ideally at or below cap |
| Compliance margin vs. cap (tCO₂e) | Positive (above cap) | Near zero or negative (at/below cap) |
| Indicative annual penalty ($) | Potentially significant recurring cost | Reduced or eliminated, depending on margin |
| Annual energy cost ($) | Based on current usage and tariffs | Lower if savings occur as planned |
| Simple payback (years) | Not applicable | Shows how long savings may take to recover capital |
Who should use this planner and when
This tool is most useful for:
- Owners and managers of NYC buildings that are likely covered by Local Law 97 (commonly over 25,000 sq ft, or part of a campus exceeding that size).
- Energy consultants and engineers running quick what-if scenarios with different retrofit bundles, emissions factors, and REC strategies.
- Financial and asset managers comparing the long-term cost of doing nothing (penalties) versus investing in efficiency and electrification.
Local Law 97 includes multiple compliance periods (such as early caps starting in 2024 and tighter caps for 2030 and beyond). The Compliance Year input lets you tag each scenario to a particular period, but you are responsible for entering the correct limit intensity and penalty assumptions for that year.
Assumptions, limitations, and important notes
This planner is for educational and planning purposes only. Key limitations include:
- User-supplied data: All emissions factors, LL97 limits, and penalty rates come from your inputs. The tool does not automatically update for regulatory changes.
- Simplified math: Calculations use annual averages and simple payback. They do not include time-varying rates, financing costs, inflation, tax incentives, or complex cash-flow modelling.
- No official determination: Results are not an official LL97 compliance ruling, inspection, or engineering opinion. For binding guidance, consult the New York City Department of Buildings and qualified professionals.
- Scope and data quality: The planner assumes that your floor area, energy use, and emissions boundaries are consistent with LL97 reporting rules. Inaccurate or incomplete inputs will produce misleading outputs.
- Policy evolution: Local Law 97 rules, enforcement approaches, and eligible compliance pathways may change over time. Always verify current requirements against official NYC resources.
For detailed regulatory information, refer to official NYC Local Law 97 materials and implementation guidance, and consider engaging an experienced energy engineer or attorney for project-specific advice.
Why Local Law 97 Planning Matters Now
New York City’s Local Law 97 sets aggressive carbon caps for buildings over 25,000 square feet, with penalties reaching $268 per metric ton of CO₂ above the permitted threshold. The first compliance period began in 2024, but the most stringent limits arrive in 2030. Waiting until the last minute risks costly fines, rushed retrofit contracts, and limited access to incentives. This calculator helps property managers, co-op boards, and energy consultants translate emissions limits into actionable retrofit plans. By comparing baseline intensity against future thresholds, you can see whether envelope upgrades, electrification, and renewable energy purchases will close the gap or if additional measures are required.
Many building owners rely on simple spreadsheets or vendor proposals that focus on energy savings alone. Local Law 97 requires a carbon lens: electrification can reduce on-site emissions but may raise electricity consumption, and offsets such as renewable energy credits (RECs) have limited applicability. The Retrofit Planner combines energy and carbon accounting while also surfacing financial impacts so decision makers can balance compliance with affordability. It handles both electric and fuel energy streams, applies user-defined emission factors, and calculates whether RECs or other clean energy purchases can bridge the final compliance gap.
How the Model Computes Compliance
The tool first calculates baseline emissions using the intensity you provide. Gross floor area multiplied by baseline intensity yields total kilograms of CO₂-equivalent. Converting to metric tons provides a reference point for penalties. It then compares this baseline to the allowed emissions for the compliance year, which equal the target intensity times the same floor area. The difference highlights how far the building must reduce to avoid fines. Next, the tool estimates post-retrofit emissions by applying projected energy savings and renewable purchases to your current energy usage.
Electricity savings reduce both cost and emissions. Fuel savings, often from boiler retrofits or heat pump conversions, cut natural gas or oil usage. Renewable purchases are credited against electric consumption, reflecting the city’s allowance for RECs sourced from Tier 4 projects. The core equation governing post-retrofit emissions is shown below.
Here, represents baseline electricity use, is projected electric savings, is renewable energy credit volume, is the electric emission factor, is baseline fuel use, is projected fuel savings, and is the fuel emission factor. The expression assumes RECs offset electric load first. Negative values are prevented by clamping energy terms to zero so the model never credits more savings than physically possible.
After calculating post-retrofit emissions, the tool converts them into intensity (kg per square foot) and compares the result to the target. Any excess translates into penalties using your specified rate. Energy savings also feed into financial metrics: electric savings multiplied by your electricity rate plus fuel savings multiplied by the fuel rate yield annual utility cost reductions. Adding maintenance savings captures efficiencies like reduced boiler servicing or fewer emergency repairs. Net annual benefit equals the sum of energy and maintenance savings minus any remaining penalties. Simple payback divides the capital cost by the annual net benefit, while the carbon payback years show how long it takes to offset the embodied emissions of the retrofit if you enter a proxy such as 50 kgCO₂e per $1,000 of investment.
Worked Example
Consider a 220,000 square foot multifamily building with a baseline intensity of 9.8 kgCO₂e per square foot, exceeding its 2030 limit of 4.07 kgCO₂e. The building consumes 3.2 million kWh annually at an emission factor of 0.29 kg/kWh and pays $0.21 per kWh. Boilers burn 210,000 therms with a factor of 5.31 kg/therm and cost $1.20 per therm. Engineers propose a heat pump retrofit that will save 1.1 million kWh and 140,000 therms, plus targeted envelope sealing worth 80 RECs (80,000 kWh). Maintenance savings are estimated at $85,000 annually, the capital plan totals $5.8 million, and the penalty rate remains $268 per metric ton. Entering these figures shows post-retrofit emissions drop to roughly 1,020 metric tons, below the 895 metric ton limit but within striking distance. Annual penalties vanish, utility savings top $1.1 million, and the simple payback falls just under five years—useful data for co-op shareholders weighing special assessments.
Scenario Comparison Table
The following table illustrates how incremental measures stack together for the example building.
| Package | Emissions Intensity | Annual Penalty | Annual Net Benefit | Simple Payback |
|---|---|---|---|---|
| Do nothing | 9.8 kg/sq ft | $1.25M | - $1.25M | n/a |
| Boiler tune-up only | 7.5 kg/sq ft | $620k | $190k | 14 years |
| Heat pump + envelope | 4.6 kg/sq ft | $0 | $1.19M | 4.9 years |
Seeing each package quantified helps boards justify deeper retrofits instead of incremental fixes that still miss the limit. Documenting penalties in the same table as energy savings reframes Local Law 97 conversations from optional upgrades to mandatory compliance strategies.
Linking to Related Planning Tools
Use this planner alongside the building-embodied-carbon-calculator.html when evaluating shared systems or steam loop conversions. If electrification is on the table, combine results with the heat-pump-operating-cost-estimator.html to understand load shifts on your electric tariff. For financing conversations, the renovation-loan-payment-calculator.html can model loan amortization relative to the net benefits calculated here.
Limitations and Assumptions
The calculator assumes all RECs directly offset electric load, aligning with current guidance but subject to change. It treats emission factors as static even though New York’s grid is greening; consider updating the electric factor for later compliance years. The model does not account for peak load implications or demand charge changes, which could matter for multifamily buildings with high plug loads. Likewise, it ignores capital incentives such as NYSERDA grants or federal tax credits that shorten payback. Finally, the simple payback metric does not incorporate discount rates or inflation; use more sophisticated financial models for investment-grade decisions.
Despite these caveats, the Retrofit Planner offers a transparent, defensible approach to Local Law 97 strategy. Revisit the analysis annually as utility rates, emission factors, and tenant loads change. Pair the quantitative insights with stakeholder engagement to ensure residents understand both the climate benefits and the financial realities of the chosen retrofit path.