SAF Aranet4 Home: Wireless Indoor Air Quality Monitor for Office or School (CO2, Temperature, Humidity and More) Portable, Battery Powered, E-Ink Screen, App for Configuration & Data History

After manual calibration, this is a very awesome battery-powered CO2 sensor
I’ve owned several CO2 sensors. In particular, I’ve had 2 Awair Glow units, 1 first-generation Awair unit, 1 second-generation Awair unit, and a TIM10 CO2 sensor. Of these sensors, the TIM10 is my “gold standard” sensor, but it has the very, very annoying property of requiring AC power. Aranet4 promised to be a battery-powered CO2 sensor that could output data to an app. It delivers, but it requires calibration out-of-the-box, in my opinion.Measured against known good sensors (particularly my TIM10), my Aranet4 sensor read about 75ppm higher than the environmental level out-of-the-box. The app warns you that performing calibration will permanently erase the factory calibration data, which is somewhat scary, but I did it anyway. In order to validate that the calibration was successful, I had my trusted TIM10 sensor outdoors, connected to AC power, out of the sun, with the Aranet4 directly next to it, on a substantially windy day with extremely good air quality (as measured by PM2.5 and PM10 presence from AirNow and Purple Air). The floor, outdoors, in this configuration, as read by the TIM10 unit, was 380ppm of CO2. Before calibration, in the same environment, Aranet4 reported 480ppm. After calibration, Aranet4 reported within 15ppm of TIM10, which I considered a success, particularly given the rarity of having such a low reading. All of the Awair units bottom out at 400ppm.Following calibration, for the last few weeks, I’ve kept an eye on Aranet4 and TIM10 when they’ve been in the same room. There’s approximately a 10-15ppm disagreement between TIM10 and Aranet4, which I consider a very acceptable deviation given that Aranet4 is battery powered, and TIM10 is AC powered.On the app side, Aranet4 provides a serviceable iOS app. The iOS app itself is perfunctory. It provides graphing, exporting data (as csv, including CO2, pressure, humidity, temperature, and date of sample), and basic reporting features. It doesn’t support dark mode, though, as an example of its perfunctory nature. The app developers didn’t consider the performance impacts that storing all of the data would have on the graphing component, though, so the app gets laggier the more data the sensor measures. You’re also only going to get a week of data for historical measurement.Other details are worth mentioning beyond the sensor accuracy and app integration, though. E-ink, as a display type, is just awesome. It looks very nice, aesthetically. Each refresh blanks the screen temporarily, though. Keep this in mind, if you decrease the measurement interval (you can measure as frequently as once per minute). Also, there’s no backlight, which is why the battery life is good, but keep this in mind too, if you want to see it in the dark.I’ve taken this sensor on an airplane, and it works great there too. It’s just an incredible sensor to have — you can pocket it or bring it somewhere in a backpack and still have CO2 measurements, where most sensors can’t go. For travel, or just in general, it’s a great device to have. After calibration, it measures very accurately, and I’m happy with my purchase all around. However, I’d say calibration is mandatory.I’ve included a screenshot of a graph made from the CSV, as well as the CSV data from the unit itself.

Living in a closed space with generally poor ventilation in an apartment, is the reason why I purchase this product. However , after been using it for over 2 weeks now, I have come into conclusion that most of us may not even need it because the CO2 in a closed space in my apartment rarely goes above 800ppm throughout the day. The only situation where it can go above 800ppm is when gas stove is used. However, carbon dioxide monitor or reader can be useful if you live in a rather tight space whereby there are three or more occupants as CO2 is mainly produced by respiration or breathing other than from burning gas. As you can see in the picture here, the screen on the aranet 4 is quite a bit sharper and contrasty than the inkbird and the design is more attractive due to semi transparent plastic case and the underlying board design is partially visible whereas inkbird has a bit of off-white coloration. The measurement is very similar to one another due to similar NDIR sensor used. As mentioned, the main deciding factor whether you need this or not is how many occupants in a space or how crowded the space is. More people occupying same space at same time, the higher the CO2 produced. For the app, I like how you can just drag along the chart to see the reading. However, aranet app only allows 7 days of data to be kept on the device before it gets overwritten where as the inkbird can keep data on the device for up to 30 days. Basically, aranet app is more polished , however, data storage is only limited to 7 days when set to 5 minutes measurement interval instead of 30 days (on device) to 1 year on inkbird (only when is synced to the phone).Addendum : Aranet has released a firmware in Dec 2023 that allows you set how long the data can be stored on the device and this depends the measurement interval, i.e. 2 minutes interval equivalent to 7 days of storage; 5 minutes for 15 days ; and 10 minutes for 30 days of storage .Besides CO2 readings, you will also get ambient temperature, humidity and atmospheric pressure readings. However, this device is not equipped with complete suite of air quality sensors, what is missing out here are quite substantial and these include volatile organic gas (VOC) , radon, particulate matters , carbon monoxide which are important parameters to determine the air that you breath is safe. And of course to have all these sensors included in an air quality monitor will costs a fortune for regular consumer.The Bluetooth range on the Aranet 4 is slightly shorter than inkbird from the distance I tested. 7-8 meters on inkbird vs 6 metres on aranet4.aranet 4 has a hidden feature of boosting it’s Bluetooth range at presumably small cost of battery life by a toggle under Bluetooth setting of the app to about the same range as inkbird.One important thing when placing the double AA battery in, is quite different from other device, make sure you place the positive side first then only negative due to there is a plastic lip at the positive side.Battery is super long lasting due to energy efficient E ink display and low energy Bluetooth and especially interval measurement is set to 5 or 10 minutes. Downside to this is that you can only get Bluetooth connection to sync the data to phone rather than wifi and can’t assess the data if not in the Bluetooth range or if away from home. Aranet claims there is a smart home integration app called homey but I guess it can be complicated to setup due to the integration is not mainstream like homekit or google home.

Funktioniert wie beschrieben!Tolles Produkt, wenn auch preislich sehr hoch!

Love the fact that this monitor actually works. It is small enough to transport in a small bag if needed. Having the app is excellent. It is worth the cost.