Xiaomi has started selling the Xiaomi Smart Temperature and Humidity Monitor 3 Pro in China, and the name undersells it. Along with temperature and humidity, this one measures carbon dioxide, which makes it a basic indoor air quality monitor for about $19.
Not much has changed on the outside. It keeps the squircle shape and the white ABS plastic shell of the earlier models. Still no other colors, which would be nice to see. There are two buttons on the right side, and the monitor either stands on a flat surface or clings to anything metal through the included magnet attachment and stand.
Xiaomi smart temperature and humidity monitor 3 Pro Features
The LCD shows the time, the date (day and month), temperature and humidity. CO₂ is the real news. Xiaomi says it uses Sensirion’s latest-generation sensor, which monitors indoor levels continuously instead of sampling occasionally. CO₂ builds up fast in a shut bedroom or a small home office, and that is usually when the air gets stuffy and you get sleepy. A number on the screen tells you it’s time to open a window.
The monitor talks to a Bluetooth Mesh gateway over Bluetooth 5.0. Through the Mi Home app you can link it to air conditioners, air purifiers, humidifiers and smart curtains, and you can scroll back through past readings.
Power comes from a single CR2450 coin cell, which Xiaomi says should last up to a year. It’s on sale now on Xiaomi’s Youpin store for CNY 129 (about $19 or €17).
There’s no word on a global launch yet. The regular Monitor 3 and the Monitor 3 Mini (€16.86 on Amazon.de) both sell outside China, so I’d expect the Pro to show up eventually.
