The HVAC Duct Sizer application allows you to quickly size one HVAC duct run or a range of duct sizes. Think of this application as a digital version of the classic Trane ductulator.


You can specify the total airflow in CFM (or L/s), the aspect ratio, and either the total velocity of air or the friction loss per 100 feet (30 meters). The results include both the exact and rounded height and width (or diameter) dimensions and the calculated velocity and friction loss.


You can specify additional parameters such as the duct shape (rectangular, round, or oval), the air temperature and the air pressure. You can also choose to display values in either english or metric units.


This application uses slider controls that allow you to quickly increment or decrement the input values and immediately observe the calculated results.

If you are analyzing an existing duct system, there is an option to input the existing duct dimensions and air velocity to derive the calculated airflow and duct friction loss.


You can also specify minimum and maximum duct friction loss and airflow values to view a range of duct sizes that fall within the bounds of the duct friction losses.




The Duct Sizer app includes functionality that allows you to send an HTML email and .CSV (spreadsheet) attachment that includes all of the inputs and results. The following is a partial screenshot of the HTML email:


This application is available to display both english and metric units.

The HVAC Duct Sizer application was designed by Carmel Software Corporation, a leader in HVAC design software since 1995. In fact, our software currently powers the analysis capabilities of Autodesk's (makers of AutoCAD) 3D modeling software tools. Also, ASHRAE has hired Carmel to custom develop the mobile apps for their various standards.

Click here to go to Apple iTunes to download the HVAC Duct Sizer app.