AirGradient ONE Review: A Nine-Sensor Indoor Monitor Built for Home Assistant
The AirGradient ONE is an indoor air quality monitor for people who want the raw data rather than a friendly voice assistant readout. It covers the pollutants that matter indoors (PM0.3, PM1, PM2.5 and PM10 particulates, CO2, TVOC and NOx) plus temperature and humidity, shows them on a built-in OLED screen, and feeds them into Home Assistant. The trade-off is ecosystem reach: Home Assistant is the only supported platform, so there is no Alexa, Google Home, HomeKit, SmartThings or Matter path. At its premium price it makes sense for a data-driven smart home, not for someone who just wants a voice assistant to say the air is fine.
- Home Assistant users
- CO2 and ventilation tracking
- Allergy and particulate monitoring
- Data-focused smart homes
Pros
- Broad sensor suite: PM0.3, PM1, PM2.5, PM10, CO2, TVOC and NOx
- Temperature and humidity tracking on the same unit
- Native Home Assistant integration
- Built-in OLED screen shows readings without a phone
- Air quality, temperature and humidity alerts
- History records and automation support
Cons
- Home Assistant only: no Alexa, Google Home, HomeKit, SmartThings or Matter
- Wired USB-C power with no battery option
- Indoor only, with no weather resistance rating
- Monochrome screen with no touch input
- No carbon monoxide or radon sensor
- Premium price for the category
- One year warranty
Who is the AirGradient ONE for?
This is a monitor for someone who already runs Home Assistant and wants indoor air quality as a first-class set of entities to graph and automate on. It is a wired desktop or shelf unit, powered over USB-C, with a 1.3 inch OLED screen so the current readings are visible without opening an app. If your smart home is built around Alexa, Google Home or Apple HomeKit, none of those platforms are supported here, and that single fact decides whether the AirGradient ONE fits your setup.
What the AirGradient ONE measures
The sensor suite is the reason to buy it. On particulates it reports PM0.3, PM1, PM2.5 and PM10, which covers everything from ultrafine combustion particles that reach the bloodstream up to the coarser dust and pollen that irritate the nose and throat. It also tracks CO2, the pollutant most tied to stuffy rooms, poor sleep and trouble concentrating, along with TVOC for the aggregate level of volatile organic compounds coming off cleaners, glues, new furniture and aerosols, and NOx for nitrogen oxides from traffic and combustion. Temperature and humidity round it out, so you can correlate a humidity climb with mold risk or a CO2 spike with a closed door.
What to know before you buy
Home Assistant is the only integration: Google Home, Alexa, Apple HomeKit, Samsung SmartThings, IFTTT and Matter are all unsupported, so there is no voice control and no cross-ecosystem sharing of the readings. It is a wired device with no battery option, so it stays where a USB-C cable reaches. It carries no weather resistance rating and is strictly an indoor unit (AirGradient's Open Air is the outdoor-rated model). The screen is monochrome and not a touchscreen, so it is a readout, not a control surface. On sensors, note the two gaps: there is no carbon monoxide sensor and no radon sensor, so this does not replace a CO alarm or a radon detector. Warranty coverage is one year.
Is the AirGradient ONE worth it?
It sits at the premium end of the category, and what you get for that is sensor breadth plus alerts and history rather than ecosystem convenience. Air quality, temperature and humidity alerts are all supported, readings are recorded over time so you can spot patterns like cooking spikes or a room that never ventilates, and automations can act on those readings. If those graphs live in Home Assistant alongside your ventilation or purifier, the price buys real capability. If you would have used it through a voice assistant, a cheaper monitor with broader platform support is the better call.
Frequently asked questions
Does the AirGradient ONE work with Alexa, Google Home or Apple HomeKit?
No. Home Assistant is the only supported platform. Google Home, Alexa, Apple HomeKit, Samsung SmartThings, IFTTT and Matter are all unsupported, so there is no voice control.
What does the AirGradient ONE actually measure?
Particulate matter at PM0.3, PM1, PM2.5 and PM10, plus CO2, TVOC, NOx, temperature and humidity.
Does the AirGradient ONE detect carbon monoxide or radon?
No. It has neither a CO sensor nor a radon sensor, so it is not a substitute for a carbon monoxide alarm or a dedicated radon detector.
Can the AirGradient ONE run on batteries or be used outdoors?
No to both. It is powered over USB-C with no battery option, and it has no weather resistance rating, so it is an indoor device. The Open Air is AirGradient's outdoor-rated monitor.
Can you read the air quality without opening an app?
Yes. It has a 1.3 inch monochrome OLED screen that displays the current readings on the device itself.

