Terrestream
Indoor Air Intelligence
About
Monitor your home's indoor air quality and receive actionable guidance. Understand how outdoor conditions impact your air and make informed decisions about ventilation and filtration.
What's New in Terrestream
1.1.1
September 30, 2026
Terrestream 1.1.1 makes it easier to compare your rooms at a glance. • The Rooms view now has a separate 24-hour chart for CO₂, IAQ, VOC and NOx, with a consistent color for each room. Open any chart to explore 6, 12 or 24 hours of readings. • The large Home Screen widget now shows up to five rooms, with all four readings and color-coded status dots. • Refined the large widget layout so the home Air Index and room readings fit more comfortably.
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FAQ
What does Terrestream do?
Terrestream is a companion app for Terrestream indoor-air sensors. It allows you to monitor your home's air quality, understand outdoor influences, and receive practical guidance on how to improve your indoor environment.
What air quality readings does Terrestream track?
Terrestream tracks CO₂, calculated IAQ, particles, VOC and NOx indices, temperature, humidity, pressure, and ambient light. VOC and NOx are relative indices that show changes over time.
Can I see historical air quality data with Terrestream?
Yes, Terrestream allows you to compare rooms and explore 8h, 24h, or 7d of history. You can inspect actual readings and zoom into changes to understand patterns over time.
Does Terrestream work on Apple Watch?
Yes, Terrestream offers an Apple Watch companion app. This makes it easy to check your home and rooms, review window guidance, and follow airing sessions directly from your wrist.
How does Terrestream provide guidance?
Terrestream connects readings, room differences, and changes over time to explain possible causes and suggest useful actions. It considers outdoor conditions and forecasts to help you decide when to ventilate.
What devices is Terrestream compatible with?
Terrestream is available for iPhone and Apple Watch. It requires a compatible Terrestream indoor-air sensor to function.
Is Terrestream free to use?
The basic Terrestream mobile app is included with the purchase of a compatible sensor and is free to use. An optional Pro subscription is available for longer history and advanced insights.
Does Terrestream have ads?
No, Terrestream does not contain advertisements. The app is free to use with a compatible sensor, with an optional paid subscription for enhanced features.