Local Law 97 compliance requires a covered New York City building to keep its annual carbon emissions under a building-specific cap. Building automation is one of the factors that can bring emissions down, and also measure the reduction. Functional Devices, Inc. manufactures the RIB® (Relay-In-a-Box®) Trifecta—relays, current sensors, and power supplies—that building automation systems use.
What Is Local Law 97?
Local Law 97, enacted as part of the Climate Mobilization Act in 2019, sets annual carbon emissions limits on most New York City buildings over 25,000 square feet—a distinction that applies to roughly 50,000 buildings citywide. A building that exceeds its limit faces a penalty of $268 per metric ton of carbon dioxide equivalent emitted over the cap, assessed every year, with no upper ceiling.
For most buildings, HVAC is the largest single driver of emissions, typically accounting for roughly 40% of a building’s energy use. This is why focusing on mechanical and control systems can make a big difference when it comes to achieving LL97 compliance.
Local Law 97: The 2030 Cap
The first compliance period (from 2024 to 2029) was set with limits that most buildings already met. By the Department of Buildings’ own review, close to 89% of covered buildings came in at or under the 2024 cap without making any changes. However, beginning in 2030, the limits tighten by roughly 40% for the second compliance period. City analysis projects that somewhere between 57% and 63% of covered buildings will exceed the 2030 cap if their owners make no changes to their current emissions.
What this essentially means is that the LL97 compliance question is not yet resolved. A building that was compliant in 2024 may no longer meet LL97 requirements in 2030. And, at $268 per metric ton over the limit, a mid-size commercial building emitting a few hundred tons over the 2030 limit will owe six figures a year, every year it remains non-compliant.
How the Automation Layer Reduces Emissions
Local Law 97 scores a building on its carbon emissions, and the simplest way to lower carbon emissions is to run carbon-producing equipment more efficiently. This is one of the functions of a building automation system, or BAS. For example, a BAS can automatically turn equipment off when a space is unoccupied, or stage on rooftop units, chiller stages, or boilers only when necessary. This lowers emissions by letting the automation system run mechanical equipment only when and as much as the building actually needs.
The RIBU1C (10 A SPDT, universal 10–30 Vac/dc or 120 Vac coil) and the RIB2401B (20 A SPDT, 24 Vac/dc or 120 Vac coil, NEMA 1 enclosure) are the general-purpose relays that building automation systems most commonly use, matching the coil to the control signal the system provides. Reliable 24V control power to a panel can come from a prepackaged RIB® power supply, which does not require a separate transformer or field assembly.
How the Automation Layer Verifies Emission Reduction
Local Law 97 scores reported, measured emissions, and a building pursuing a good-faith compliance pathway has to be certain that its planned reductions were actually achieved. This can sometimes be complicated, as a schedule that says a unit is off is not sufficient evidence that the unit is off; a seized contactor, an overridden schedule, or a Hand-Off-Auto switch accidentally left in the Hand position can keep equipment running beyond its planned timeframe.
Current sensing closes that knowledge gap. A current sensor reads the current that a piece of equipment actually draws and reports whether it is running. The RIBXGTA is a split-core current switch with a 0.75–150 A adjustable range and a dry-contact output that a building automation system reads as a runtime status point. It clamps onto an existing conductor without breaking the circuit, so it can be added to equipment in an existing building during a retrofit. This can help buildings accumulate the run-hour data that supports a reported energy-use reduction.
Frequently Asked Questions About Local Law 97 Compliance
What does Local Law 97 require?
Local Law 97 requires most New York City buildings over 25,000 square feet to keep annual carbon emissions under a building-specific cap and to file a certified emissions report each year. Buildings that exceed the cap face a penalty of $268 per metric ton of carbon dioxide equivalent over the limit, assessed annually.
When does Local Law 97 take effect?
The first compliance period started in 2024, with the first reports due in 2025 for 2024 emissions. Limits will tighten for the second compliance period beginning in 2030, and again in 2035 and 2040, moving toward a near-zero limit by 2050.
How does building automation help with Local Law 97 compliance?
A building automation system lowers emissions by running HVAC equipment only as much as the building needs, through scheduling, setback, and demand-based staging carried out by relays. It can also verify an energy-use reduction: current sensors confirm equipment ran only as scheduled, producing the run-hour record that supports a reported emissions reduction. However, automation is only one factor among several; a heavily over-cap building may need more significant changes to achieve LL97 compliance.
Why is the 2030 cap more significant than the 2024 cap?
The 2024–2029 limits were set at a level most buildings already met, so roughly 89% complied without changes. The 2030 limits tighten by about 40%, and city analysis projects that 57% to 63% of covered buildings will exceed them without action. A building that was compliant in 2024 can face six-figure annual penalties starting in 2030.
Reduce and Verify Emissions for Local Law 97
Building automation is only one factor among several when it comes to Local Law 97 compliance. A building’s emissions number is a function of its fuel source, envelope, and equipment efficiency as much as its controls, and a building heavily over its cap may need more significant changes implemented. What the automation layer can do, however, is reduce the runtime of any equipment already in place. For most buildings, it is among the lowest-cost moves available when it comes to lowering emissions.
To specify the switching and current-sensing devices a building automation system uses for emissions control, browse the Functional Devices relay and current sensor lineups, or find an authorized Functional Devices distributor in New York.