# CO2 on Watch & Lockscreen

See CO2 readings from Aranet4, Airvalent or Inkbird IAM-T1 on Apple Watch and your iPhone Lock Screen, with complications, widgets and configurable alerts.

Canonical page: https://www.tech-care.net/apps/co2-on-watch/
App Store: https://apps.apple.com/app/id6738605498
Developer: Kevin Floch, Tech Care

## Compatible sensors
Aranet4, Airvalent, Inkbird IAM-T1. A physical sensor is required. Independent companion app; use official manufacturer apps for their original features.

## Features
### A glance at your wrist
Put CO2 on your watch face with Apple Watch complications. See the latest reading without opening your iPhone, or use the three-hour history graph to follow recent changes.

### Right on your Lock Screen
Keep a CO2 widget on your iPhone Lock Screen. Check the reading and its last update time together, so you know how recent the information is.

### Alerts that fit your day
Choose a CO2 threshold and get notified when it is exceeded. Use once or repeat mode, snooze an alert, or schedule notifications for specific days with CO2⁺.

### Live Activities
Use a Live Activity to keep an active monitoring session visible on your iPhone. Background widgets and complications refresh separately, according to the time iOS and watchOS allow.

## Getting started
1. Download the app on your iPhone and connect a compatible sensor with Bluetooth enabled.
2. Add an Apple Watch complication or an iPhone Lock Screen widget.
3. Check the last update time and configure your preferred alerts.

## Questions and answers
### Which CO2 sensors work with the app?
CO2 on Watch & Lockscreen supports Aranet4, Airvalent and Inkbird IAM-T1 devices. A compatible physical sensor is required; your iPhone and Apple Watch do not measure CO2 by themselves. This is an independent companion app. Use the manufacturer’s official app for its original device features.

### Can I see Aranet4 CO2 readings on Apple Watch?
Yes. Connect your compatible sensor in the iPhone app, then add a CO2 complication to a supported Apple Watch face. Complications show the latest available reading; some styles also show recent history. Check the last update time before relying on a reading.

### Does it support iPhone Lock Screen widgets?
Yes. The app offers iPhone Lock Screen widgets so you can see the latest CO2 reading without opening the app. Widgets and Apple Watch complications are included in CO2⁺ premium features.

### Why do background readings sometimes update slowly?
iOS and watchOS control when apps, widgets and complications can refresh in the background. Updates are not guaranteed at a fixed interval and should not be treated as continuous real-time monitoring. Open the app to sync, keep Bluetooth enabled and keep the sensor within range. Always check the displayed last update time.

### What does CO2⁺ include?
CO2⁺ premium includes Apple Watch complications, Lock Screen widgets, custom CO2 alert thresholds, scheduled alerts and advanced alert modes. The app is free to test and connect to your sensor. See the App Store and the app’s purchase screen for current plans, prices and availability.

### How do the CO2 alerts work?
Choose a threshold for notifications. Once mode alerts you when it is exceeded; repeat mode continues alerting while readings remain above the threshold. Snooze options and day-specific schedules help you control when alerts arrive. Alerts depend on the readings and background updates available to the app.

### What can I do if my sensor does not connect?
Enable Bluetooth, bring your iPhone close to the sensor and check the sensor’s battery. Open the app and reconnect to the device. If the connection still fails, restart the app and try again. Contact Tech Care support if you need help.

### What do the CO2 colours mean?
Colours help you compare readings with the app’s configured thresholds. The previous default example used green below 800 ppm, yellow from 800 to 1200 ppm and red above 1200 ppm; thresholds can be customised with CO2⁺. They are display settings, not a guarantee of safe air. A CO2 sensor does not measure every indoor pollutant.

## Support and privacy
Support: https://www.tech-care.net/contact-support/
Privacy: https://www.tech-care.net/privacy-policy/