⭐⭐⭐⭐☆ (4.5/5 — loses half a star for making me re-learn what a “radius heel” is)

Let’s be honest: most people download software for games, photo editing, or cheating at solitaire. HVAC engineers? We download databases of loss coefficients. And somehow, I’m genuinely excited about this one.

Over 1,200 fittings. Elbows, tees, transitions, wyes, boots, and that one weird fitting that looks like a M.C. Escher drawing. Each one includes loss coefficients (dynamic losses, not static—don’t @ me) that actually match ASHRAE’s latest research. Version 6.0 adds more rectangular and spiral fittings, plus better support for AutoCAD/Revit exports. Yes, it’s still an Excel-based interface from 2005, but somehow that makes it feel earnest .

Here’s an interesting, slightly tongue-in-cheek review of ASHRAE Duct Fitting Database Version 6.0 , written as if by a veteran HVAC engineer who’s seen it all. Finally, a spreadsheet that understands my ductwork existential crisis

ASHRAE Duct Fitting Database v6.0 is the boring hero we deserve. It’s the digital equivalent of a perfectly sealed, well-insulated duct run—efficient, reliable, and utterly invisible to the outside world. If you design commercial HVAC systems, this free download just saved you 47 hours of thumbing through Fundamentals handbooks.

Final line: If you’ve ever muttered “coefficient of local resistance” out loud in public, this is your GOTY.

Get it from the official ASHRAE website (not a random HVAC forum from 2014). Your future self—sitting in a mechanical room at 2 AM, balancing a system—will thank you.