So here's the deal: the unit is nice and seems to be calibrated relatively well. The literature that comes with it says it has +/- 10% error window. This perhaps seems extreme, but we have to remember this is a consumer unit and the professional models are an order of magnitude more expensive. For my part, I'm satisfied with the accuracy because the readings I'm getting are almost identical to those of a professional home inspection company. The alarm does function well; ours has gone off at least twice in the last week (we are seeking remediation) and I've been able to hear it upstairs although it doesn't strike me as obnoxiously loud as a fire alarm. But you do still hear it. Now my MAJOR quibble with this unit: it will chart all the data points and show you your history and median and peak values. Great. But it does not chart this data relative to TIME. In other words, you can export 200 readings and they will just be 1, 2, 3, 4,...200 etc. The radon in my home cycles. There's a peak and trough every day and the pattern repeats itself daily. What time of day did it peak 4.71 and again a day later 4.2? I have NO IDEA. I just see a peak, but I don't know the date or the time. This strikes me as unbelievably dumb, for a unit that is bluetooth connected, has a color screen, and can communicate with an app on my phone. You mean to tell me it can't also log the date/time of each reading? a couple bytes of text data? You've got to be freaking kidding me. I've sent a message to the developers and I realllly hope they update the firmware/app to accommodate this function. It is such a glaring omission I cannot believe it made it to market without it. I would send it back for this reason alone if it weren't for the fact that a.) it seems to be giving me accurate readings and b.) it's a bit of hassle for me to ship it back at this point and c.)similar units with fancier apps have a fair number of bad reviews with people complaining they are not accurate. I'm still peeved though.

Without another accurate Radon detector with which to compare, it’s hard to tell how accurate this one is but the readings have been consistent since it was activated and it makes sense that the average is in the low 1’s in a newly constructed home built with radon barrier/exhaust. This device gets high marks for being easy to read and understand as well as being able to access it on the iPhone and iPad. I rated down one star on ease of use since the included instructions were unclear about which app to download for use - the third one I tried “RadonEye” (not Plus) was the correct version and it worked instantly once I used that.

Initial impressions going on 3 days use: Came packaged like an apple product - nice. Set up was a breeze. Plugged it and, then downloaded app and one tap connect by blue tooth. First reading in about 10 minutes. Works as advertised. The app is simple, allows you to switch between units, adjust alarm (on/off, alarm value, and interval). Main page shows current reading, day average, and month average. Plus current measurement duration. Will update later. Concerns so far: 1. Quick set up instructions were clear. English user manual was not - i am guessing it was written by a Korean with english as a distant second language. 2. Documentation states the sensor calibration is only good for 2 years. Nothing in the documentation about what to do after 2 years - recalibrate or throw it away? 3. App - Main page of app has a lot of unused real estate - which is frustrating since much of the info displayed is in very small font (other than current reading). Would love it if they would increase the font and clearly display all info. You can see a graph of data, but no way to share the data except through itunes. 4. Unit - only complaint so far is that it needs to be plugged into an outlet. I'd prefer battery power to make it easier to place this where i want and in case of power outages. All in all, happy with purchase so far.

Update (08/20/2020): There is a new app now available which is much better than the prior version. The old app didn't auto update to the new app. One has to download the new app and delete the old one. The new app is lot better with ability to delete a saved data file, uses the full screen space, has ability to zoom in on the data etc. There could be lot more things one can add and make it better but I am happy with what they have done with the app. So, raising to four star from my original three start rating. Original Review: The Radon Detector seems to work fine. It detected high Radon levels in my basement and I ended up converting the passive venting system to an active venting system by installing a radon always on fan. The detector showed that the radon level dropped to an average of 2pCi/l from above 4pCi/l. The biggest complaint I have with this radon detector is the iPhone application. Firstly, you do need the application as there is only limited information on the Radon Detector screen itself. If you want to look at history of the readings or change any settings etc. then the app is a must. The application has very limited functionality and lacks basic features. For ex, if you accidentally save a chart you can never delete it. The app is not even optimized for the taller iPhone X screen and it looks archaic. There is no way to zoom into the chart or check any specific data point until and unless you download the data in excel. And yes, the app does allow data download to excel once you save a file within the app. The last update for this app was 9 months ago and that makes me wonder if the company has already dropped support. Once the app stops functions this Radon Detector would be quite useless as the application provides the only way to change setting and extract data for this detector. Another annoying part is that the app description in the Apple app store is all written in Chinese (or a similar script). Thank god at least the app itself is in English! I understand the need for multiple languages but at least English should be there.

I own 3 Radon monitors. The RadonEye, an Airthings Wave (2nd gen), and Corentium Home (also by Airthings). The Airthings monitors have had questionable accuracy over the past 11 months. The RadonEye has been much more accurate when comparing all 3 monitors to charcoal test results. That said, the most important thing about a Radon monitor is accuracy. I recommend this product based on accuracy alone. Additionally, I like that I can get a quick reading by looking at the small display on the device. The bluetooth sync functionality actually works fine between floors/walls, so lack of wifi connectivity hasn't been a problem. I love that you get your first accurate reading after only 1 hour with this monitor. The Airthings Wave takes a whole week to calibrate and they say to let it run for at least 30+ days to consider the readings accurate. I dock 1 star from the RadonEye for the following reasons though: - The app seems outdated aesthetically. When compared to the Airthings app and web dashboard it leaves a bit to be desired. - Learning how the RadonEye takes measurements can be a little confusing at first. It takes a reading every 10 minutes and then spits out an avg every hour. In the app these are called "data points" and graphed out as pci/l on the y axis and # data points on the x axis. I wish this graph was more of a time based graph, rather than showing how many data points you have and requiring you to do your own math to figure how long the monitor has been measuring, or the time a reading was taken based on those data points. - This isn't a very attractive device. Just a white cylinder with a screen on it. - I wish this had a longer power cable, or was battery operated. Being tethered to a wall socket limits the positioning of the monitor. Overall, despite my issues with the RadonEye, it's all about the accuracy in the end, and this thing has it. I recommend this product if you're in the market for a "smart" Radon monitor.

While I do not have another radon detector to compare the accuracy of the readings, they do seem to change based on conditions as I would expect. The readings are higher in the morning, and go way down when I open a window, so I think they are realistic readings. The app is good, too, but nothing fancy. Would purchase it again if I needed to.

I am working as engineer in development of similar products (alarms and indoor climate rcontrol). Last year I bought product of Airthings because my house is located in an area with pretty huge of the radon activity. So I have more one year experiency with this product. It is good product for end user. It gives good and easy read out information. If you are not pushing for fast results this product gives you information what you buy for. But my expectations are little bit higher and I need faster information to be able to recognize in few steps where is radon source and base on this to do some measures to mittigate this. I have levels in my house within 100-400Bq in living part of my house and also above 1000Bg in pillar and other technic rooms located underground. Fortunately there are no hallway between and these spaces are separated by a radon insultion. Depends on wheater conditions is possible to measure level as 5000Bq (!!!) it is temporary but in coherence with weather. So why I am writing about - because this product fulfill my expectations well and it is really able to find a source of problems. I also did some easy comparations with Airthings product and have to say that results are fully within my expectations. First feeling was the same in plenty of commnets giving low ratng for this product, but after long period observation the results are comaprable. Is necessary to take into consideration that these products (both of mentioned) are consumer electronics not equipments for a laboratory or scientific measurements. In this price level it could be sign as one of the best products. In comaprison with Airthing there would be fine to do some improvement. But also Airthings App has its own cons e.g. graphs readibility for weak eyes (my case). One technic information at the end of my quite long assesment (sorry for that). The physical principle of radon activity detection says that the bigger detection chamber the better and faster results are. Radon Eye has few times bigger chamber in comparisson with not only with Airthings but maybe among of all in this level of comparable end user oriented products.

Very simple to use and gave us the same readings as the test kits we had just used. This cost less than having someone come out and test for you. And, the beauty of this little gem, is I got to test my son's house too. We will be having remediation done on our house because of the high readings and it will be nice to check on the system installed to see if it works. Most new homes built these days are so tight in construction that it is almost impossible not to have high radon readings in many parts of the country.

Did a lot of research on Amazon before buying this device. I formally had the carbon short-term test done to my home office in the basement. The results came back 1.6 and 3.9 next to the sump pump. Measured this in summer and the numbers were already borderline for mitigation. I just couldn't imagine what the readings would be like in winter. Since I spend 8-10 hours a day in the basement, I thought it would be a worthwhile investment to purchase this. I am not disappointed. Provided readings within 10 minutes. It peaked around 4.5. I was able to measure the affect of the air composition when I opened the basement windows. After several hours the radon levels went down to 0. So opening the windows does actually help. Thanks to this fast response device, I will move my home office upstairs to avoid further exposure. I will continue to open the windows daily before we install a permanent mitigation solution. I really like the fact that it stores up to one year of data to measure both the mid term and long term averages. I can see the data points on my phone for the hourly average. Setting it up was really easy, just plug it into the wall and download the app (optional). No pairing required, it just picked up the device. As for shipping, it was fast and came within 2 days.

During my home inspections prior to purchase my inspector found my radon levels elevated, so purchased this to monitor my levels prior to remediation. Turns out this device is very accurate in comparison to the two professional hired out tests that were preformed in my house. The device beyond plugging it in, and pairing their mobile app with the device over bluetooth it was up and running within minutes. Really love this and will continue to have it run all the time in my lower level to ensure my radon levels stay low also awesome I can get my reading from my phone. I love the graphs it produces as it stores all the data it gathers to show the long term averages of your radon numbers.

very easy to install and connect to phone, love the app which can show history data. I did a lab test to confirm the reading and they match very well. never have to worry about radon anymore

The Radon Eye has worked well for me over the 3 weeks that I have had the product. Both the LED display and phone app provide useful data. The logged data is especially useful to observe radon level trends. While the logged data can be displayed in the app being able to transfer the logged data to a computer and to import it into Excel is nice as it allows you to manipulate and process the data however you like. The fast response time of this product allows for meaningful readings of short term variations of radon levels. The Radon Eye's current reading on the LED display and logged data points are rolling 1-hour average values. The other radon meter I have used (Pro Series 3) requires 48 hours of data to provide an accurate reading and it only displays 1 week averages for its short term output. That long averaging period makes the Pro3 less useful in correlating events that cause rises and falls in radon levels. The one week average values from the Pro3 appear to track reasonably well with the 1 week averages from the Radon Eye. I have observed that short term variations are strongly tied to weather conditions. Cold/cool mornings and rainy periods appear to correlate to significant rises in radon levels. I have only used the product in one location so far (living room), but may relocate it once a longer period of data collection has occurred.

I bought this unit because we were finishing our basement and my kids were going to be spending a lot of time down there. I wanted to see what the radon levels were. Set up was easy peasy and it seems to work great! It samples every 10 minutes and plots the values out on a chart. It also tracks peak value, 30-day average, and 1-day average. It showed that the radon values in my basement weren't considered drastically "unsafe" per US standards (over 4.0 pcl), but it was higher than what I was comfortable with so I had a company come and install a radon mitigation system. After that, the unit immediately started reading much lower levels which was great for my peace of mind. Overall, seems like a great product which I have recommended a few times to others. Way better than those one-time, set it out then mail it in tests that only show one reading. If you want to know exactly what your radon levels are at any given time, buy it!

I am finishing my basement and wanted to know my radon level as I will soon be spending more time in the basement. All you have to do is plug in the unit and place it where you want to get a reading. After about 15 min you will get your first reading, however, it is best to let it sit for a day and then observe the average. The accompanying app makes it very easy to download a graph history of your radon levels. I found out that the radon in my basement was above 10 pCi/L. This is well above the US EPA safe threshold of 4 pCi/L. As I am not particularly interested in me or anyone else in my family getting lung cancer, I had a radon fan installed. After installation of the fan, I used this RD200 to observe the efficacy of the suction fan. My radon dropped from 10+ pCi/L to 0.6 pCi/L. More important to this review, the reading on my RD200 matched the reading on radon mitigation company’s professional radon meter. I feel very confident the radon measurements from this unit. I also like that this unit has an alarm if the radon level exceeds a set value (mine is set to 4 pCi/L). This unit gives me piece of mind that my family is not breathing dangerous air.

I use this device to continuously monitor radon in a house with significant radon risk. Most importantly, I had a professional home inspector drop off a monitor and was able to validate this results of this device against a calibrated unit +/- 5%, close enough to call it perfect. For the cost, you can't beat it, I'd recommend testing this device with a calibrated unit to make sure. But once that's done it's invaluable, particularly in my case as I built a DIY radon abatement system (which worked in bringing my levels from 72pC/l to ~1). A python api is published as well, so I use a raspberry pi to pull readings and post them to a website so I can share my triumph against radon with friends.