Local Law 87 (LL87) is a regulatory mandate implemented in New York City aimed at improving the energy efficiency and sustainability of buildings. Enacted in 2009 as part of the city’s broader sustainability efforts, LL87 requires large buildings to conduct periodic energy audits and retro-commissioning measures to identify and rectify inefficiencies in their energy systems. These audits assess the building’s energy usage patterns, HVAC systems, lighting, insulation, and overall operational practices to pinpoint areas where energy conservation measures can be implemented.