HVAC Duct Design

1. Scope and contact

This policy covers HVAC Duct Design, a duct sizing and pressure-drop calculator for iPhone and iPad provided under the Set In Stone brand. “We” refers to the app provider identified on the App Store listing. Contact [email protected] with “HVAC Duct Design privacy” in the subject for questions or requests.

Information kept on your device is separate from purchase information processed through Apple and RevenueCat, information you voluntarily send to support, and requests made when you visit this website. This policy describes the app version audited October 30, 2026.

2. Jobs, runs, and preferences on your device

When you save a job, HVAC Duct Design stores its name, an optional address and optional notes that you type, the dates it was created and last changed, and the duct run you built: each section’s name, airflow, length, round or rectangular size, fittings, and which section it follows. Calculated results such as pressure drop are recalculated from those values. Jobs are kept in a local database on your device.

The app also stores your preferences: imperial or metric units, your default friction rate, maximum velocity, longest rectangular shape, and size increment, plus whether you finished onboarding and which onboarding screen you reached. Answers you choose during onboarding, such as what you design or how you size ducts today, are used only to shape those screens and are not saved or sent anywhere.

The app does not require a Set In Stone account, does not upload your jobs, addresses, notes, or calculations to a developer-operated server, and does not synchronize them through iCloud. We cannot recover jobs from a server.

3. Sharing a job summary

Share is optional. When you choose it, the app builds a plain-text summary of the job you selected, including its name, address, notes, sections, and totals, and hands it to the iOS share sheet. What happens next depends on the app or service you pick, such as Messages, Mail, Notes, or Files, and on that service’s own terms and privacy notices. We do not receive the summary and cannot see where you send it.

4. Purchases and RevenueCat

HVAC Duct Design is unlocked with a one-time lifetime purchase. Apple handles payment. RevenueCat receives purchase records and entitlement information so the app can verify and restore your purchase. Requests use a randomly generated app-user identifier and the technical information needed to operate the purchase service, such as app version, device and operating-system details, and the network address used to reach their servers. The identifier is not a name, email address, or login.

Your jobs, addresses, notes, and calculations are not sent to RevenueCat. We do not receive full payment-card details. Apple and RevenueCat also process information under their own notices, available at https://www.apple.com/legal/privacy/ and https://www.revenuecat.com/privacy-policy.

5. Support and website requests

When you email support, we receive the address you use, your message, and any attachments you choose to send. Do not send sensitive information that is unnecessary for the request. The app never attaches your jobs to an email on its own.

This static website is hosted by Cloudflare. Website delivery may involve information such as your IP address, requested page, browser details, and operational or security logs.

6. What the app does not collect

In the version audited October 30, 2026, the app does not request or use your location, contacts, photos, camera, microphone, motion sensors, health data, or advertising identifier. It does not include advertising, behavioral analytics, crash-reporting, or third-party tracking SDKs, and it does not track you across other companies’ apps and websites. The only third-party software included for operation is the RevenueCat purchase library.

If a future version adds any of these, this policy will be updated first and, where required, you will be asked for permission in the app.

7. Purposes and legal bases

Jobs, runs, and preferences let you size ducts, keep your work, and have the app behave the way you set it up. Purchase processing provides and verifies paid access and restores it when you reinstall or change devices. Support information is used to answer your request, troubleshoot problems, and handle related disputes. Website information supports delivery and security.

Where privacy law requires a legal basis, processing needed to provide the app features and purchase you request relies on performance of a contract; responding to support and securing services may rely on legitimate interests, balanced against your rights. Consent is used where required. Legal obligations may require retention of certain records.

8. Retention, deletion, and backups

Jobs stay on your device until you delete them. In the Jobs list you can delete a job after confirming, which removes the job and its sections from the local database. Preferences stay until you change them or delete the app. Deleting the app removes its local jobs and preferences from your device, but not purchase records held by Apple or RevenueCat, and it does not change your lifetime purchase.

Device or computer backups made by iOS, iCloud, or Finder may retain copies of the app’s data according to your backup settings, and restoring a backup may bring back jobs you deleted since. The app does not provide a separate cloud backup. Because jobs are local, we cannot restore a job you deleted or lose on a device.

Support information is kept as reasonably necessary to address the request, follow-up, disputes, or applicable recordkeeping requirements. Purchase-service records are retained as needed to provide access and support and meet applicable obligations. Independent providers determine retention for their own records under their notices.

9. Security and international processing

Local storage relies on the operating system’s app sandbox and your device security, including your passcode and device encryption. Purchase services and website hosting may process information in countries other than yours, including through Apple, RevenueCat, and Cloudflare. Their privacy notices explain their practices.

No storage or transmission method is guaranteed secure. Protect your device, passcode, and backups. We do not promise custom end-to-end encryption, guaranteed recovery, or a developer-operated backup of your jobs.

10. Rights and requests

Depending on applicable law, you may have rights to access, correct, delete, obtain a copy of, restrict, or object to processing of personal information we hold, and to withdraw consent for consent-based processing. These rights have lawful conditions and exceptions. You can review, edit, and delete your jobs directly in the app.

Email [email protected] with your request. We may need proportionate information to verify it. You may have a right to complain to your local privacy regulator. Requests about your Apple Account and payment records should also be directed to Apple. We cannot remotely retrieve or inspect jobs stored only on your device.

11. Children and policy changes

HVAC Duct Design is a professional and hobbyist calculation tool and is not directed to children under 13. We do not knowingly collect personal information from children. If a child has sent personal information to support and you wish to request its removal, contact [email protected].

This policy is effective October 30, 2026. Relevant changes will be published on this page with a revised date, with additional notice or consent where required. Future account, synchronization, advertising, or analytics features would require an updated assessment and notice before release.