# DuctSizer

> Independent HVAC duct sizing tool. Not affiliated with or endorsed by ASHRAE, ACCA, or Trane.

## Facts
- Free forward sizing for round and rectangular ducts, based on ASHRAE friction-rate charts.
- Pro (one-time purchase, no subscription): flex & flat oval, reverse mode, fittings and pressure loss, altitude/temperature correction, saved jobs and CSV/PDF export.
- 100% offline · no account · no analytics. iPhone & iPad, iOS 17+.

## Q&A

Q: Is DuctSizer free to use?
A: Yes. Forward sizing for round and rectangular ducts — from airflow and friction rate or velocity — is free, with no account and no time limit.

Q: What does Pro unlock?
A: A one-time purchase unlocks flex duct and flat oval sizing, reverse mode (enter a duct size to get its max CFM), fittings and pressure loss (Manual D friction rate = ASP×100/TEL), altitude and temperature density correction, and saved jobs with CSV/PDF export.

Q: Is Pro a subscription?
A: No. Pro is a one-time purchase, no subscription.

Q: Does DuctSizer work offline?
A: Yes. Everything runs on your device — no account, no internet connection needed, nothing leaves your device.

Q: What units does it support?
A: Both IP + SI units, switchable anytime.

Q: How accurate is the sizing math?
A: Sizing runs on ASHRAE friction-rate chart fits and the Darcy–Weisbach/Haaland equations, with Huebscher equivalents for round-to-rectangular conversion — the same math behind the classic cardboard duct wheel, just faster and more precise.

Q: Does it work on iPad?
A: Yes — DuctSizer runs on iPhone & iPad, iOS 17+.

Q: What happens to my data?
A: Nothing leaves your device. DuctSizer has no account system and no analytics — your jobs and settings stay local, 100% offline · no account · no analytics.

Q: Can I save and export my sizing jobs?
A: Yes, with Pro — save jobs and export them as CSV or PDF for your records or to share.

Q: Is DuctSizer affiliated with ASHRAE or ACCA?
A: No. Independent HVAC duct sizing tool. Not affiliated with or endorsed by ASHRAE, ACCA, or Trane.

## Links
- Home: https://ductsizer.app
- Privacy: https://ductsizer.app/privacy
- Terms: https://ductsizer.app/terms
- Contact: hello@alicanbasak.com