Privacy Policy - Duct Calc

Last Updated: July 20, 2026

Overview

Duct Calc is an HVAC duct-sizing calculator for air-conditioning and ventilation engineers, developed by WittyApps. All calculations run entirely on your device. We collect a minimal amount of anonymous data to keep the app reliable, described below.

Information We Collect

• Anonymous usage analytics (via Amplitude): which calculators are opened and whether the Pro unlock screen is shown or purchased. No names, emails, or account identifiers exist in the app, so none are collected.
• Crash reports (via Sentry): if the app crashes, technical details (device model, OS version, stack trace) are sent so we can fix the bug.

We do NOT collect your dimensions, airflow values, inputs, location, contacts, photos, or any personally identifying information. There are no accounts and no advertising.

How We Use Information

Usage analytics tell us which calculators matter so we can improve them. Crash reports tell us when something breaks so we can fix it. Nothing is used for advertising, profiling, or cross-app tracking, and data is never sold.

Data Storage

Your last-used settings and Pro purchase state are stored only on your device. Deleting the app removes them. Analytics and crash data are stored by our service providers (Amplitude, Sentry) under their own security policies.

Third-Party Services

• Amplitude (anonymous product analytics) — see Amplitude's privacy policy.
• Sentry (crash reporting) — see Sentry's privacy policy.
• Apple App Store / Google Play (in-app purchases) — payment is processed entirely by Apple or Google; we never see your payment information.

Your Rights

Analytics data is anonymous and cannot be tied back to you, which means there is no personal profile for us to access, correct, or export. If you have any concern, contact us and we will help.

Data Security

Your dimensions and inputs never leave your device. Analytics and crash data are transmitted over encrypted connections (HTTPS).