Privacy Policy · Sun Sizer Pro

Last updated September 26, 2026

The short version We don't collect any of your data. There's no account to create, no ads and no tracking. Your projects are saved on your device and, if you leave iCloud sync on, in your own private iCloud, which only you can access. We never see them.

This policy covers the iOS and iPadOS app Sun Sizer Pro and its free companion Sun Sizer (“the apps”), published by Tachena under the name Chie (“we”, “us”).

Information we collect

None. We don't run servers for the apps, and the apps never send your projects, measurements, location or anything else to us or to any third party. We have no way to view your data.

Data stored on your device

Projects, saved calculations, your equipment library and settings are saved on your iPhone or iPad first. Everything works offline. The data is also included in your device's normal iCloud or computer backup if you use one.

iCloud sync

Sun Sizer Pro can keep your projects, saved calculations and equipment library in sync across every iPhone and iPad signed in to your Apple Account. It uses Apple's CloudKit and stores the data in your private iCloud database, which belongs to your Apple Account and counts toward your iCloud storage. We can't access it, and neither can anyone else. Apple handles it under the Apple Privacy Policy.

Sync is on by default. You can turn it off in Settings → iCloud sync, and the app then keeps everything on that device only.
If you aren't signed in to iCloud, your data stays on the device.
Deleting a project while sync is on deletes it from iCloud and from all your devices.
The app also stores one small flag in iCloud so the starter equipment is only added once per account.

Some settings are never synced: the active project, units, display settings and quick-calculation fields.

Location

If you tap Use my location and allow access, the app reads your location to fill in a site's latitude, longitude and altitude, and to find true north when measuring a panel. The calculations run on your device. The coordinates are saved only in the project you're working on, which syncs through your private iCloud if sync is on. You can refuse or revoke location access at any time in Settings and type coordinates in by hand.

Camera and motion sensors

Measuring tools use the motion sensors and, for the camera tools, the camera (ARKit) to measure tilt, direction, distances and heights. This happens on your device in real time. The apps don't record, save or upload any photos or video.

Notifications

If you start the free trial and allow notifications, the app schedules one reminder on your device for the day before the trial ends. It's a local notification: nothing is sent to us or to a notification service.

Climate data

Sunlight and temperature figures come from a NASA POWER dataset built into the app. Looking up a site doesn't contact NASA or any other service.

PDF reports, project files and sharing

When you export a PDF report or share a project file, the app creates it on your device and hands it to the iOS share sheet. You choose where it goes, and the app you pick handles it from there.

Purchases and the free trial

Premium and the 14-day free trial are in-app purchases processed entirely by Apple through the App Store. The trial is a free (no-charge) purchase so that it stays with your Apple Account across devices and reinstalls. We never receive your name, email, payment details or Apple Account information. Apple gives developers only anonymous, aggregated sales figures.

Analytics, advertising and tracking

The apps contain no advertising, no analytics and no third-party tracking code, and they don't track you across other companies' apps or websites. If you've chosen to share crash data with app developers in iOS Settings, Apple may send us anonymous crash reports, which we use only to fix bugs.

Children

The apps are professional tools and are not aimed at children. We don't knowingly collect information from anyone, including children under 13.

Deleting your data

Delete projects in the app (with sync on, this removes them from iCloud and all your devices too). Deleting the app removes its data from that device. You can also manage what apps store in your iCloud from your Apple Account settings.

Changes to this policy

If a future version changes how the apps handle data, we'll update this page and the date at the top before that version is released.

Contact

Questions about privacy? Email tachena@me.com.