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

The aranet4 is such an excellent monitor, and really is the best bang for your buck in an accurate and easy to use monitor. We have used this in all the rooms of our home to measure air flow and how quickly C02 builds up - especially useful in the kitchen during various cooking processes and in the bedrooms overnight - but we have also brought it to work to measure the C02 and get an idea of the air flow in various offices as well. It's easy to set up, the battery life is excellent, and it's easy to bring with you anywhere. The app works well and is likewise a quick and easy setup. We keep this monitor in the main living area of our house and it's every easy to monitor when the C02 is accumulating and we need to crack a window or turn on an exhaust fan. It's been illuminating. This item is also very accurate, and more so than others and cheaper version. Totally worth the money and a reliable, trustworthy device for monitoring a really important aspect of our health.

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.

I got the SAF Aranet4 Home mainly because I was curious about why I'd get so groggy in one particular room of my house. This little gadget was easy to set up right out of the box and it immediately started giving me the lowdown on my air quality. Turns out, the CO2 levels in that room were off the charts sometimes - no wonder I felt like I was in a brain fog half the time.I love that the Aranet4 is portable. I've taken it with me on trips, and it's kind of become my travel buddy. It’s wild to see the CO2 levels on airplanes and in hotel rooms. The color coding on the device makes it super easy to understand when the air quality is getting bad, and the buzzer is a neat feature too, although I turned it off after a while because it startled my cat.The app is simple and does the job. It keeps a record of the air quality data, so I’ve started geeking out on comparing the air quality in different places I go. The e-ink display is clear, and the battery just keeps going - haven’t had to charge it yet!The Aranet4 is not just a fancy gadget; it’s been a real eye-opener for me. It made me realize how the air quality around us can affect how we feel. Now, instead of guessing, I know when to crack open a window to get some fresh air in. It’s pretty satisfying to see the CO2 levels drop and feel that mental clarity kick in. Honestly, in these COVID times, it’s comforting to have a better grasp on the air I’m breathing, especially in new or unfamiliar places.So yeah, I’m really glad I got the Aranet4. It’s helped me understand my spaces better and take simple steps to improve the air quality around me. Plus, it’s kind of fun having this little gadget with me, measuring the unseen world of air quality wherever I go.Update: have lent the device to several friends now to test their apartments, and they've all found ways to improve their air quality!

Easy to setup. Small footprint and very portable. No annoying LED lights. Accurate compared with other sensors I have. Calibrated CO2 when I got it. Able to change the thresholds for green/yellow/red. Bought one for the bedroom and the temp and humidity only to monitor the attic. Bluetooth range is pretty good on “extended”.