Airflow, Ducts and Air Conditions

Use these tools for the air side of a system. The duct calculators size round and rectangular ducts from airflow, the CFM calculator finds the airflow a room, load or duct needs, and the psychrometric, dew point and wet-bulb calculators give the properties of moist air from temperature and humidity.

Tools in this group

• CFM Calculator (Cubic Feet per Minute) — Pick what you know — room air changes, heat load, tons, duct velocity or a bathroom — and get the airflow in CFM, m³/h and L/s.
• Dew Point Calculator — Enter the air temperature and relative humidity to get the dew point, or work back from a dew point to the humidity.
• Duct Size Calculator — Enter the airflow and a friction rate or velocity limit to get the round duct size, its velocity and rectangular equivalents.
• Duct Sizing Chart (CFM by Duct Size) — Pick a friction rate and duct material to build the CFM chart for round and rectangular ducts, or look up one airflow.
• Psychrometric Calculator — Enter the dry-bulb temperature and one more property to get every moist-air property and see the state on a psychrometric chart.
• Wet Bulb Temperature Calculator — Enter the air temperature and humidity to get the wet-bulb temperature, or calculate WBGT from measured readings.