Terms of Use
Last updated: 2026-07-03
Independent engineering tool
Independent HVAC duct sizing tool. Not affiliated with or endorsed by ASHRAE, ACCA, or Trane. Sizing results are estimates based on published ASHRAE-derived methods — they are a starting point for a design, not a substitute for the judgment of a licensed engineer or for compliance with local building and mechanical codes. Always verify duct sizing against the codes and standards adopted in your jurisdiction before installation.
Purchases
A one-time purchase, no subscription unlocks Pro features. Purchases are handled by Apple under the App Store terms; refunds are managed by Apple, not by us.
Acceptable use
DuctSizer is licensed for your personal or professional use in sizing ductwork. You may not redistribute, resell, reverse-engineer, or scrape the app or its content.
No warranty
DuctSizer is provided “as is”, without warranty of any kind. While we build the sizing math to match published ASHRAE-based references, we don’t warrant that every result is free of error or fit for a particular project. To the fullest extent permitted by law, we disclaim liability for any loss or damage arising from reliance on the app’s output — always confirm sizing against your local codes before installation.
Changes
We may update these terms from time to time; the “Last updated” date above reflects the latest revision.