HVAC reference
Technical reference
Use the tables below to check a unit conversion, formula input, or geometry relationship. They do not replace project design criteria, a complete pressure-path review, local requirements, or qualified HVAC design.
Capacity and units
Capacity and unit conversion
Check thermal-capacity units and reference rows before comparing ratings or converting a documented load.
Airflow and volume
Airflow and room-volume checks
Use these formulas and conversion tables to keep CFM, ACH, room volume, and metric airflow units consistent.
Duct design
Duct geometry and resistance scope
Review geometry and straight-duct relationships before checking velocity, fittings, and the complete pressure path.
HVAC Duct Size Chart
Check round-duct area rows before a velocity review.
DUCTEquivalent Round Diameter
Review equal-friction examples without treating them as direct substitutions.
DUCTDuct Friction Rate Reference
Understand the straight-duct friction calculation boundary and missing losses.
TOOLDuct Friction Loss Calculator
Check a transparent straight-round-duct Darcy-Weisbach calculation.
Load planning
Load calculation context
Use the maintained guide and calculator to document preliminary inputs without treating a shortcut as final equipment design.
Refrigeration
Capacity and state-point units
Use these unit relationships after documenting refrigerant, state points, and measurement locations.
Psychrometrics
Moist-air property lookup
Check variable definitions, IP/SI units, and the conditions needed to compare one air state with another.