Aranet4 HOME Wireless Indoor Air Quality Monitor measuring CO2, Temperature, Relative Humidity and more

IoT devices that measure air quality are becoming increasingly common. I reviewed the Foobot back in 2017, then the Airthings Wave Plus in 2019. Recently I have been testing the Aranet4 HOME from the Latvian company SAF Tehnika.

While the effects of high levels of CO2 were long thought to be benign, research has found that concentrations as low as 1,000 ppm can affect people's cognitive function and decision-making performance.

Typically we worry about the concentrations of Carbon Monoxide, when not enough oxygen or ventilation is provided to a fire, dangerous levels of Carbon Monoxide can build up and be fatal.

There are not really many Co2 devices on the market, though here are a lot of air quality monitors, which monitor different things like Volatile organic compounds (VOCs).

By using the Aranet4 app on your smart device, it is possible to wirelessly access the real-time data and up to one week of historical measurement data.

Aranet4 HOME: Wireless Indoor Air Quality Monitor for Home, Office or School [CO2, Temperature, Relative Humidity and more] Portable, Battery Powered, E-Ink Screen, App for Configuration


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Precisely monitors indoor air quality – CO2 (actually measures CO2 level), Temperature, Relative Humidity and Atmospheric pressure in Real-Time
Visual and Sound Warnings when CO2 concentration gets too high
Power efficient E-Ink display ensures super long battery life for this wireless device (up to 2 Years)
Smartphone app for historical data viewing (supports iPhone and iPad with iOS 12 or later, Android devices with Nougat 7.0 or later, compatible with Bluetooth 4.1 or later)
Works with the powerful Smart Home platform Homey!

Set up

The Aranet4 device is calibrated at the factory. However, you can perform CO2 calibration manually when needed. For the sake of this review, I left the device in its factory-calibrated setting.

The Aranet4 uses AA batteries which are supplied, and this should last you a couple of years. When you open the battery cover, you will notice some small switches, these can be used to do the calibration, switch the temperature between °C / °F, switch Bluetooth on or off, and also enable connectivity with the Aranet PRO base station (which is not relevant to this review).

Nothing else needs to be done on the device itself. To access the data history and tweak setting further, you will need to download the Aranet4 App and pair up the devices.

Pairing up is simple, and from within the app, you can change the measure update interval, which will affect battery life and storage duration.

You can also have it set off a buzzer if the Co2 goes over 1400ppm then it is also possible to alter the Co2 indicator  to be focussed on humans or...