HVAC Duct Sizer for the Apple iPhone/iPod Touch

Click here to go to Apple iTunes to download this app.

(Click here for the detailed help file that is included with the app.)

The HVAC Duct Sizer iPhone application allows you to quickly size one HVAC duct run using the constant friction method. 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.


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, Autodesk (the makers of AutoCAD) acquired our load calculation software and incorporated it into their leading 3D modeling software called Revit.

If you have comments or questions, please submit comments here.

(Click here for the detailed help file that is included with the app.)

Also, look for future iPhone applications from Carmel including pipe sizing, load calculations, duct fitting analysis, and much more.

Click here to go to Apple iTunes to download Duct Sizer.