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

This doesn’t monitor for VOCs or PM levels, but if you’re looking for a reliable, low-power, long lasting, wireless (Bluetooth) monitor for CO2, temperature, and humidity, then this is it. The design is about as dead simple as it can get. There is no magnet in this case. If you want to attach it to something, I use 3M Command Strips, and they work very well for me. You don’t have to worry about brightness, because the display is high resolution e-paper, which gives it the super long battery life. Just shine a light on the display, and you will be able to very easily read it. Battery life is measured in terms of multiple months, at least. It is very much a set-and-forget type of device, once you have it wherever you want to measure air quality and temperature. Some well-known travelers even take them onboard airplanes, to help them gauge the quality of the air they are breathing while flying. For me, the only downside is that they connect with Bluetooth (BLE), so while you can connect to them from the Aranet app from pretty much wherever they are or you are in your home, you can’t connect them to your home wifi, so that you could make them part of a broader home air quality monitoring system. For that, you would want the AirThings brand instead. But for a small, portable (if you want), easy to read, Bluetooth accessible air quality/temperature/humidity monitor with an easy-to-use remote monitoring app, you can’t beat this device. Especially not at this price.

We have been using this carbon dioxide (CO₂) monitor for the past 18 months to check carbon dioxide levels in our home and work areas. CO₂ levels are a key measurement to assess the quality of indoor air and ventilation, which are important for minimizing the risk of virus transmission. One of the main reasons we bought it was to monitor how good the ventilation is in our indoor rooms. For example, in our home office, when the readings went up to 1,000+ ppm (parts per million), we noticed that our thinking slowed and we felt more sluggish. Decisions become more difficult to make. Apparently, our experiences match scientific studies that have proven that high levels of carbon dioxide can impair cognitive function and make it harder to think and be productive when CO₂ levels hit 1000 ppm and above. Thanks to this air quality monitor, we also noticed that if a second person enters a room, the CO₂ levels can increase quite rapidly just from our breathing. The CO₂ readings can sometimes double. We open a window to bring it back down to a good range. This monitor is small enough so that you can hold it in your palm and move it around easily. It looks both sleek and functional. Big bonus: it also provides temperature and humidity readings, and you can select either Fahrenheit or Celsius. To have all these readings all on one small device is very handy. It runs on two AA alkaline batteries, which are included. There is a helpful bar showing how much battery life is left. We have had our unit for 18 months, and after continuous use, we have not had to replace the batteries. The e-ink display digits are bright, easy to read, and large (roughly half an inch tall). The large digits and color bar allow you to quickly glance at the device from a distance and assess whether to take action to reduce CO₂ levels. There is an air quality bar that has three colors: green, yellow, and red. Each color corresponds to a different CO₂ level: green for normal (good), yellow for elevated (average), and red for high CO₂ levels (unhealthy). The second reason we purchased this monitor is to get an idea of how high the risk of respiratory virus exposure is. Higher CO₂ levels indicate poor ventilation, which can lead to higher airborne virus concentration. Scientists have found that people in a room with higher CO₂ levels are at a higher risk of virus infection than people in an identical room with lower CO₂ levels. Therefore, knowing when the CO₂ levels are high allows you to know when to reduce risk by opening windows to allow fresh air in, wearing a high-quality respirator mask, and/or reducing the time spent in that space. One feature we like is that you can use it with or without the app. So there is no pressure to use the app. Our only wish is that it came with a protective cover. In sum, this is a high-quality, reliable, and easy-to-use CO₂ monitor that allows you to continually assess air quality and ventilation. This was quite an investment, but well worth it. Highly recommended.

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!

I purchased the SAF Aranet4 Home after hearing it mentioned on the The recent Tim Ferriss Show, where a guest recommended it for monitoring indoor air quality. After using it myself, I can see why it’s well regarded. What I liked: The E-ink display is very clear and easy to read at a glance Displays CO₂, temperature, and humidity in real time Portable and battery powered, so it’s easy to move between rooms Good to know / what could be clearer: The sensor takes about 5 minutes to stabilize after being moved. This wasn’t clearly mentioned in the product description or on the packaging. When I first tested it and carried it between different rooms—and even outside—the readings stayed the same, which briefly made me think the unit might be defective. I later learned (after reading other customer reviews) that this is normal behavior.

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.

Great CO2 monitor and surprisingly accurate but will require some times to align up to other CO2 monitors I have. It takes about 15-30 minute to be steady and all is good. There's a default 5 minute sample rate, but it can be changed via the app with increments of 1, 2, or 10 minutes. I have a competing brand that I like to compare to and it's within +2 to 35 ppm measurement. Humidity reading is a bit off, but I do not care much about that since this is focused on CO2 mainly. The e-ink display is perfect, and easy to read in front of a light. Just wish this thing have Wi-Fi capability though because even with Bluetooth, it doesn't reach far enough from my kitchen; which is about 25 feet away from the device. Battery life supposedly going to last a while thanks to the e-ink display though.

I love this device and bring it everywhere with me. The display is intuitive and easy to read, easily connect by bluetooth to my phone and other devices, the responsiveness can be updated to short intervals for constant monitoring room-by-room or set to longer time durations if the unit will be stationary in one room for a while. Easily switch between metrics. A+ for indoor air quality awareness!

Excellent produit. Les mesures son fiables l'appareil est compact et utilise la technologie NDIR. Il est possible de le recalibrer. L'application pour téléphone mobile est très intuitive elle offre une foule de paramètres et permet une visualisation sous forme de courbes des différentes mesures (CO2, température, hygrométrie, pression atmosphérique) sur une journée, une semaine ou une période au choix. La connexion utilisée dans mon cas est le Bluetooth, elle est extrêmement réactive et économe en batterie. Hormis sont prix élevé il s'agit d'un excellent produit.

Der CO2 Sensor ist gut und sicher verpackt. Macht einen wertigen Eindruck und sieht gut aus. Dank der Verwendung normaler Batterien und seiner geringen Größe kann man ihn einfach mal in ein anderes Zimmer stellen oder mitnehmen. Viele andere vergleichbare Geräte haben einen kurzzeitigen Akkubetrieb oder erfordern einen Netzanschluss. Die Bluetooth-Verbindung mit der zugehörigen App ging schnell und einfach. Die Verbindung ist stabil. Kein Re-Connect erforderlich wenn man zB außer Reichweite war. Die Anzeige am Gerät ist gut ablesbar. Meist schaue ich aber über die App, da hier auch der zeitliche Verlauf angezeigt wird. In der c‘t 27/2023 war ein Bericht über CO2 Messgeräte und der Aranet4 hat mich trotz des hohen Preises mein Interesse gefunden. Das hat sich im Betrieb bestätigt. Mit dem Gerät und der App bin ich sehr zufrieden. Was negativ zu erwähnen ist, ist die starke Preiserhöhung um €30 wohl zum Februar 2024. Ende Januar hab ich noch €179 bezahlt, aktuell kostet er €209. Versand kommt schnell aus Lettland (EU) mit €10 VK.

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.

The Aranet 4 Home definitely lives up to expectations. It is accurate, portable, easy to use, and has long-term data. Battery has been excellent even with 1 minute readings. Would recommend waiting for a sale when possible though. It would be nice to see another product with the same great attributes but with added PM2.5 readings.

I sleep with my wife in a small room and I've always been curious as to the amount of CO2 that accumulates if we have the door closed. We soon discovered that closing the bedroom door with only one person sleeping sent the CO2 levels quite high. Needless to say because of our new monitor we now sleep with the door open. The bluetooth app is neat and keeps a running log/graph of your CO2 levels. The batteries are supposed to last for a very long time. .. Not much to complain about functionality wise. The low/med/high level indicators along with the precise reading display are nice and easy to read. Very pricey and only splurged on it because it was recommended by a family member. Glad I purchased it but I still smart when I think how much I had to pay for it. I would recommend to anyone who is concerned about the air quality within the home.