Ashrae Fundamental Handbook | ULTIMATE · 2025 |

1. Overview & Purpose The ASHRAE Handbook—Fundamentals is the premier reference for the basic principles and essential data governing heating, ventilation, air conditioning, and refrigeration (HVAC&R). Published by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), this volume is systematically updated every four years to reflect current research, standard practices, and code requirements.