Breathe Better. Live Smarter.®

The air you live in, finally understood.

Know what changed. Know what to do.

One $249 USD indoor air-quality sensor that watches the room across twelve signals, fuses them with live outdoor data, and turns every spike into a single clear next step. The device, web dashboard, and mobile app are all included.

Terrestream device showing live indoor air-quality readings
The device: twelve live signals, a screen, and a 15-LED color underglow.

One-time

$249 USD

The device, web dashboard, and mobile app - with AI that turns your air into clear, actionable insights.

Buy Terrestream

Twelve live signals

  • CO₂ 540 ppm
  • IAQ 32
  • PM1.0 3 µg/m³
  • PM2.5 5 µg/m³
  • PM4.0 9 µg/m³
  • PM10 14 µg/m³
  • VOC 80 index
  • NOx 6 index
  • Temp 71 °F
  • RH 44 %
  • Press 1014 hPa
  • Light 300 lux

Simulated dashboard · Columbus, OH

Indoor CO₂ 540 ppm · Good
24-hour CO₂ trend
Outdoor · live Storm · AQI 18
88°
  • RH60%
  • Wind12 mph
  • PollenLow
Weather · AQI · pollen · smoke

Everything is in a healthy range right now. Nothing to do.

Try a scenario

Outdoor data fused with your room, turned into clear actions, in the web dashboard and mobile app. What's in Pro →

US pricing and fulfillment Shown in USD. Free US shipping, applicable tax calculated at checkout, FCC documentation published.

* Matter is bridged through the Home Assistant Matter plugin, exposing Terrestream to Apple Home, Google Home, and Alexa.

Cost and subscription

One-time hardware. No subscription required for the core experience.

Buy the sensor once. The app, dashboard, 90-day history, core AI, and local integrations are included. Pro is optional when you want unlimited history, shared-household features, and deeper automation.

  • Today$249 USD
  • Required subscription$0 USD/mo
  • Optional Pro$3.99 USD/mo

Hardware

Terrestream sensor

$249 USD

One-time purchase for the twelve-signal indoor air-quality sensor.

  • No required subscription
  • Fast FedEx shipping and a 1-year limited warranty
  • Start with one room, then add coverage room by room

The sensor keeps working even if you never activate Pro.

Included with every sensor

Free

$0 USD/mo

Everything most homes need: the device, web dashboard, mobile app, 90-day history, local smart-home, outdoor-data fusion, and core AI insights.

Local display, Home Assistant, MQTT, and local API workflows keep working without a paid plan. Read the pledge.

  • All twelve signals, screen & underglow
  • Web dashboard + mobile app
  • Home Assistant, MQTT, local API, Matter via HA
  • Outdoor data fusion + AI insight cards
  • 90-day history

Yours to keep.

Optional upgrade

Pro

$3.99 USD/mo

Billed monthly · cancel anytime. Free for 3 months with every new sensor.

  • Everything in Free, plus:
  • Unlimited history + CSV export
  • Advanced pattern detection + recurring-event explanations
  • Wellbeing, pet & sleep-environment lenses
  • Cloud automations + advanced notifications
  • Family Circle (up to 6) + annual report

Activate Pro after you create an account. Cancel anytime; local and Free features remain available.

Start with the sensor. Free is included. $249 USD today. No required subscription. Pro stays optional after setup.
Buy Terrestream

What changes if you add Pro?

Free is the complete day-one product. Pro extends history, collaboration, and advanced intelligence.

Capability Free Pro
Device and local network
All twelve signals, device screen, and 15-LED underglow
Standalone offline operation
Local HTTP API, Home Assistant, and MQTT
Matter to Apple Home, Google Home, and Alexa through Home Assistant
Dashboard and history
Web dashboard
History retention 90 days Unlimited
CSV exports and long-range comparisons Recent only
Family Circle, up to 6 members
AI and recommendations
AI insight cards and basic recommendations
Weather, AQI, pollen, and smoke data fusion
Advanced pattern detection and recurring-event explanations
Wellbeing, pet, and sleep-environment lenses
Cloud-mediated automations and advanced notifications
Annual year-in-air report

Formal feature details live in the binding feature matrix, which controls. Core sensing works on day one.

Hardware

What Comes In The Box

Everything you need to get started on day 1.

Sensor

The Terrestream IAQ sensor with touchscreen and 15-LED underglow.

Power

UL-listed 18 W USB-C PD adapter with US and Canada plug heads.

Cable

2 m braided USB-C cable, USB-IF certified for 60 W power delivery.

Guide

Printed How to Breathe field guide for every measurement and color.

Integrations

Home Assistant, MQTT, local HTTP API, and Matter through the Home Assistant bridge.

Support

Fast FedEx shipping, setup help, and a 1-year limited warranty.

Mobile app

The whole system, in your pocket.

Your readings and AI insights on your phone, wherever you are, with an alert the moment your air needs attention. Included free.

  • Live readings from every room you watch
  • AI insights pushed the moment something changes
  • Check in and adjust from anywhere
  • iOS and Android, included with your sensor

Buy Terrestream See what’s included

Works with your home

No lock-in. No hub. Plays with everything.

Home Assistant, MQTT, and a local HTTP API out of the box; Matter to Apple Home, Google Home, Alexa, and SmartThings through the Home Assistant bridge. Your data stays yours.

Coverage

How much of your home’s air are you actually watching?

One sensor watches one room. Air problems are local and time-shifted, the kitchen, the bedroom, the nursery, the basement each have a different problem on a different schedule. Switch on the rooms you care about and watch what each one would catch.

1 of 7 zones watched · 14% of your home
  • Zones watched1
  • Threats covered1 of 9
  • Source attribution · needs 2+ sensors
1 sensor · $249 USD $249 USD each Watch 1 room →
Quick start
Top-down floor plan with sensor-placement markers

Watching 1 of 7 rooms

Drag to rotate. Tap a marker to watch that room.

  • Primary bedroom

    CO₂ creeps to ~1,400 ppm while you sleep, and never alarms.

    CO₂ 1380 ppm
    Peaks ~3am
  • Kids bedroom

    The smallest room with the most vulnerable lungs. CO₂ builds fastest where the door stays shut.

    CO₂ 1280 ppm
    Peaks overnight
  • Home office

    The CO₂ fog that quietly tanks your focus on every afternoon call.

    CO₂ 980 ppm
    Peaks 2–4pm
  • Kitchen

    Gas-stove NOₓ and a wall of cooking particles, every dinner.

    NOx 130 index
    Peaks ~6:30pm
  • Living room

    The room everyone shares, and the first place wildfire smoke gets in.

    PM2.5 22 µg/m³
    All day
  • Garage

    CO and solvent VOCs that creep through the shared wall into the home.

    VOC 210 index
    All day
  • Basement

    Humidity, VOCs, and mold risk you’ll never smell until it’s in the air upstairs.

    VOC 180 index
    All day
  • More rooms

    A den, a workshop, a rental, a relative’s place, add a sensor for any room not on this list.

    Extra units 0

A second sensor isn’t a spare, it’s the room your first one can’t see.

Included intelligence

An AI with named jobs, not a vague badge.

Every Terrestream watches for these by name and tells you the one thing to do. All included. See the intelligence in action →

How Terrestream compares

The premium monitors are fine instruments: they hand you readings and stop. The cheap ones hand you a single number you can’t trust. Terrestream is the platform built around the instrument.

Terrestream $249 USD · one-time Premium monitors ~$300 · one-time Budget meters ~$30–70
Air signals tracked 12 5–7 1–3
Live outdoor data fused in, weather · AQI · pollen · smoke ✓ No No
Subscription required for core use No required subscription Varies Varies
Local / Home Assistant support ✓ Home Assistant · MQTT · API Limited No
Hardware price $249 USD ~149€–$329 ~$30–150

“Why not a $50 meter?” A budget meter gives you one uncalibrated number, usually CO₂ or particulates, never the full picture, that drifts over months, with no outdoor context, no app, no idea what to do about it, and no warranty when it quits. You’re not saving $200; you’re buying a number you can’t trust and can’t act on.

Comparison reflects typical consumer indoor-air monitors as of 2026; exact capabilities vary by model. Many competing monitors gate their insights behind an $8–10/month subscription.

All monitor comparisons vs AirGradient vs Ruuvi Air vs Awair vs Airthings vs Aranet4 Measurement evidence

FAQ

No fine print, no lock-in

The questions buyers actually ask before they trust an air monitor, answered plainly.

Is there a subscription?

Pro is optional. Everything most homes need works for the one-time $249 USD: the device, the web dashboard, the mobile app, live outdoor-data fusion, and core AI insights. The optional Pro tier ($3.99 USD/mo, or $29.99 USD/year, and free for your first 3 months) adds unlimited history, advanced pattern detection, family sharing, and cloud automations.

Who owns my data, and can I export it?

You do. Terrestream publishes its readings locally over a local HTTP API, MQTT, and Home Assistant, and you can export your history at any time. Cloud history and remote access are conveniences you opt into, never a lock-in.

Do I need a hub?

No proprietary hub, bridge, or base station to buy. Terrestream joins your Wi-Fi directly and exposes a local HTTP API and MQTT out of the box. Matter to Apple Home, Google Home, and Alexa is bridged through Home Assistant.

How do I get Pro?

There is nothing to add at checkout. Once you have your device and create an account, Pro activates right from the web dashboard or the mobile app. Every new sensor includes 3 months of Pro free; after that it is $3.99 USD/mo or $29.99 USD/year, and you can cancel anytime.

Do I need an account to use the sensor?

Not for local use, the device measures, displays, and publishes on your own network without one. An account is only used for cloud dashboard history, remote access, and notifications.

What smart-home integrations are included?

Home Assistant, MQTT, and the local HTTP API are part of the out-of-box experience. Through the Home Assistant Matter bridge, readings can flow into Apple Home, Google Home, Amazon Alexa, and SmartThings.

Will it still work without Wi-Fi?

Yes. Plug it in and it reads continuously on the device screen. Wi-Fi is needed for cloud history, remote dashboard access, outdoor-data fusion, and notifications.

Is this a safety device?

No. Terrestream is an indoor environmental monitor and decision-support tool. It does not replace smoke alarms, carbon-monoxide alarms, radon tests, or professional industrial-hygiene instruments.

What is included in the box?

The Terrestream sensor, a USB-C cable, a UL-listed USB-C power adapter, a printed field guide, and the software needed to see readings on the device, the dashboard, and your local smart-home.

Where is the formal feature matrix?

The binding feature matrix is published at /legal/tier-features and takes precedence over any marketing summary.

Breathe Better. Live Smarter.

Ready when your air is.

One sensor. Twelve signals. Indoor readings connected to outdoor context and plain-English recommendations. $249 USD buys the sensor and the full connected experience, no subscription required.

$249 USD one-time

Buy Terrestream Explore the sensor
  • No subscription required
  • 30-day returns
  • 1-year limited warranty
  • Fast shipping via FedEx

Six sensors. Twelve signals.

Built on genuine Sensirion, Bosch, and Texas Instruments sensors.

  • CO₂
  • IAQ
  • VOC
  • NOₓ
  • PM1.0
  • PM2.5
  • PM4.0
  • PM10
  • Temperature
  • Humidity
  • Pressure
  • Light

Included

  • In the box: the sensor, USB-C cable, power adapter, and printed field guide
  • Dashboard and mobile app included
  • Privacy-first air data

Works with

  • Home Assistant
  • MQTT
Terrestream $249 USD one-time Buy Terrestream