The McQuay DuctSizer software is a legendary industry staple, now maintained by Daikin. It is widely considered the gold standard for quick desktop calculations. Windows Desktop Application (.exe download)
Several software companies offer "free versions" of their paid ductulators to entice you to buy their full suite.
: You can email results as HTML or .CSV files directly to your desktop for inclusion in project spreadsheets. The Not-So-Good ashrae duct size calculator free download
The official is a high-precision digital tool designed specifically for engineering-grade calculations based on ASHRAE standards. While a full desktop "free download" for the complete database often requires a paid subscription, ASHRAE offers several free mobile and lite versions . Direct Download & Tool Options
When using a free calculator, inputting the correct parameters is vital to getting accurate physical duct dimensions. The McQuay DuctSizer software is a legendary industry
: It assumes you already understand concepts like aspect ratios and friction loss.
: Unlike generic "ductulators," this app accounts for air temperature, density, and atmospheric pressure based on your specific elevation. : You can email results as HTML or
Free plugins for Revit or AutoCAD that automatically size duct runs based on systemic ASHRAE parameters.
Maintained within thresholds to prevent acoustic issues. Residential main ducts typically top out at 700-900 FPM; commercial ducts can handle up to 1,500 FPM.