ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers) is the international professional organization that develops the technical standards governing HVAC system design, energy efficiency, ventilation, and refrigeration.
Key ASHRAE standards include: 90.1 (Energy Standard for Buildings), 62.1 (Ventilation for Acceptable Indoor Air Quality), 55 (Thermal Environmental Conditions for Human Occupancy), and 15 (Safety Standard for Refrigeration Systems).
Virtually every US building code references ASHRAE standards. ASHRAE also publishes the ASHRAE Handbook series — the definitive technical reference for HVAC engineers — and provides education, certification, and research programs for industry professionals.