ASHRAE design data comprises standardized tables of outdoor temperature, humidity, and weather parameters for thousands of global locations, published by the American Society of Heating, Refrigerating and Air-Conditioning Engineers. These data form the foundation for HVAC system sizing across North America and internationally, ensuring consistent engineering practice and code compliance.
Content and Standards
ASHRAE publishes design data in the ASHRAE Handbook—Fundamentals, updated periodically as weather analysis techniques improve. Each location entry includes 1% and 2.5% design dry bulb and wet bulb temperatures, mean coincident values, design wind speeds, atmospheric pressure, and latitude/longitude coordinates. The database covers over 7,000 stations globally, with expanded U.S. coverage at approximately 6,000 locations. Data incorporate National Weather Service records spanning 20-30 years of observations.
Application and Updates
HVAC designers reference ASHRAE design data when calculating peak loads for equipment selection and system design. Building codes including IECC and International Building Code (IBC) adopt ASHRAE design data values. Recent updates reflect climate change considerations, with some locations showing gradual increases in design cooling temperatures and changes in design heating temperatures, prompting discussion about update frequency and future applicability of current data.