The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) Standard 90.1-2019 serves as a foundational benchmark for commercial building energy codes across the United States. It establishes minimum requirements for energy-efficient design in most building types, excluding low-rise residential structures. These standards are frequently referenced in federal and state energy regulations and provide detailed guidance on building envelope requirements, HVAC systems, lighting, and other energy-critical components. Adherence to ASHRAE 90.1 ensures compliance with energy codes and promotes sustainability in commercial properties.