I'm really glad to have this device. When we bought our house 15 years earlier, we had done a radon test and found the levels to be low. But within the last few years I'd started using the unfinished basement quite a bit (home gym), and randomly ordered a charcoal radon test off Amazon. It took me a few months before I finally used it, but after getting the results back, I found that our radon levels were above safe limits (~10+ pCi/L). That freaked me out, and I wanted to quick answers, so I bought this Airthings radon detector from Amazon and had it the next day. It confirmed that our levels were higher than they should be. Further, it also revealed our levels were above safe limits even on the floor above the basement. I'm so glad we didn't have to wait for another charcoal test. A few days later, we had a radon system installed that basically sucks the radon out of the ground, underneath the crawlspace and concrete basement floor. This was a year ago and it has been very effective, reducing our radon levels down to a 1-year average of ~1.3 pCi/L. I've found the Airthings device to be quite accurate, nearly matching the 2-week results from an independent test using two Sun Nuclear radon testing devices. I like how quickly I can get results. For instance, I recently found that opening windows on the top level of our house causes radon levels to increase in the basement (to ~3-4 pCi/L), and this happens due to a chimney effect creating negative pressure in the house, causing it to draw more radon out of the ground. I also learned that I could prevent the negative pressure by also opening windows on the lower level of the house. If I didn't have the Airthings device, I would not be able to tell how these kinds of changes affect radon levels. For any kind of test like this, it's important to give it some time (a day or two minimum), as radon levels naturally increase and decrease all the time, so you can only trust longer term averages. And the longer the test, the more accurate the number. The Airthings device doesn't give you minute-by-minute readings for this reason. Instead, it gives you, short term 24-hour, 7-day, and long term averages, which is ideal. I also like how simple this device us, it's foolproof. There's really nothing for you to do other than finding a good place to put it, and reading its screen. There are no buttons (unless you count the tiny reset button on the back, which you may never use). It shows you the 1-day, 7-day and long-term averages by rotating the numbers every few seconds on the screen. The batteries last a really long time. We've been running the device on the original batteries nonstop for over a year, with no sign of slowing down. Lastly, I also like that you can easily test different places in your house, or even different houses (we recently tested my parents house). It would be a pain to do this with charcoal tests. I highly recommend this device, especially if a charcoal test makes you want further testing, and it is well worth the price. I can't think of any downsides and I will never be without one of these devices.

EXCELLENT radon detector. Very easy to use, read, and re-set. I've placed it in different rooms and it gives very solid readings. The battery has already lasted over 6 months. This exact detector was advised by my heating/cooling/electric company, and I'm glad I purchased. 5 stars!

[Update 2: August 2016] In Feb 2016 I ran another side by side comparison of the Corentium 223 vs the SS (Safety Siren), and this time using two charcoal tests as "controls." All four were placed around the same spot (pictures do not show the charcoal tests but they were right next to the Corentium and SS). The Corentium and the SS were turned on at the same time and allowed to run until the SS started to show a result (due to the SS not showing an initial reading until a couple days after turning it on or resetting it, whereas the Corentium starts showing a reading almost immediately). Once the Corentium and SS were on for a few days I opened both charcoal tests and left them open for 4 days (the longest time allowed by the lab to get legitimate/accurate results). Then I sealed up the charcoal tests and mailed them in and checked the readings of the Corentium and the SS which had now been on for 7-days (the reason for 7 days is that the devices both provide readings at 7 days but other readings are at different time parameters and so not comparable). The results are shown in my pics (3rd-6th pics). Charcoal Test #1: <0.5 pCi/L Charcoal Test #2: <0.6 pCi/L Corentium 223: 0.97 pCi/L ("7 days" reading) Safety Siren: 1.2 pCi/L ("S"=7 days reading) Please note that I bought both the Corentium and the SS in March 2014 and so both were almost 2 years old at this point. I'm not sure the charcoal test results and those of the Corentium and the SS can be compared directly since their readings are over different times (approximate 4 days for the charcoal test vs 7 days for the two devices; I had to do this since the charcoal tests cannot be tested for more then 4 days and the two devices do not show readings at shorter times (e.g. 3 days, etc.). Interpreting the results is not exactly easy or maybe even valid, but it does at least seem to show that the devices are not wildly different than the charcoal readings and more importantly, they seem to read higher rather than lower than the charcoal readings (i.e. they do not give falsely low readings). It also shows that the charcoal tests are very close to each other and therefore probably a reliable test (i.e. repeated testing yields values close in value to each other) and are assumed to be the most accurate way to test radon levels. Another finding is that the SS, which needs re-calibration annually, had higher values compared with the Corentium (which is not supposed to need retitration over the life of the device which is stated as about 10 years). However, when I left the two devices on for a few more days (see the 6th pic) I found that the values became much closer to each other: 0.9 for the SS and 0.94 for the Corentium. Conclusions? I would say that based on my amateur and non-expert tests and interpretation of the results, that both devices are probably reliable and accurate enough to get a decent approximation of the radon levels in your home. The SS, though cheaper than the Corentium, is uglier and needs a wall power adapter whereas the Corentium is smaller, better looking, lasts a long time on batteries, and can be hung on the wall. It also reportedly does not need re-calibration for the 10 year lifespan and so I consider the Corentium to be a superior device and would recommend it over the Safety Siren. [Update 1: March 2015] Sorry to the folks who were waiting to see the results of my side by side comparisons between this device, the Safety Siren, and the charcoal mail in tests. I've attached a photo of both detectors (along with the charcoal test, only did one of those) side by side after both had been sitting there for over a week. As you can see, the Safety Siren is set to short term reading, which I believe is the past 7 days reading, and shows at 1.6 while the Corentium shows 1.64 and is for the past 7 days also. So, based on this test (and I've done this several other times with the same, comparable results) both detectors seem to give similar readings. Of course, the gold standard seems to still be the charcoal, mail in kits and so I've attached a photo of that reading too. Basically, the kit shown in the pick was set out for the required time (48 hours) and mailed in promptly. The reading I got back from the company was 1.7 pCi/L, so pretty close to both detectors. The Safety Siren only goes to one decimal place and so is a bit more limited than the Corentium which goes out to 2 decimal places, but in reality 2 decimal places is probably not very valuable or helpful. So, to summarize, my test did show that the device is pretty accurate compared to a charcoal test and also that the Safety Siren was comparable -- although that device does not run on batteries and apparently needs to be recalibrated on an annual basis or so. The Corentium supposedly does not ever need to be recalibrated which just seems really odd to me. I will repeat these tests periodically and update this review on an annual basis (or until a better detector comes out than either of these!) to see how well the Corentium stands up over the years with regards to calibration need. I have also upgraded my rating to 4-stars. --- [Original Review: April 2014] Just want to point out that this radon detector does not wait for a couple days to give an initial radon reading, like some detectors do (like the does), so basically within a minute or so of turning this device on for the first time (or after resetting), you will start to get initial readings that are predictably around 0.00 pCi/L. Obviously, getting a reading after 10 seconds isn't helpful, and I don't understand why it would give a worthless reading instead of making you wait for the necessary time (typically 2 days with the Safety Siren Pro detector) before giving you a reading. Over the next days/weeks, the reading will often steadily increase for the same reason, making you really question how useful this device is unless you wait at least a week or so. Even then, you're not sure if the 7-day reading is a weighted average -- meaning that those early really low readings would bring the average rating lower than it actually is. When I placed the Safety Siren Pro and the Corentium side by side for about 2 days in my basement near my sump pit, the readings were dramatically different: the Safety Siren gave a 1.7 and the Corentium around 0.56. Over the next couple days (again, the initial readings were after 2 days already), the Corentium reading starting to creep upwards, going from mid-0.5s to around 1.0 and then above, while the Safety Siren Pro stayed fairly steady around 1.7 Another couple days may bring the Corentium to around the reading of the Safety Siren Pro, which would make me feel better that they're both reliable if given enough time. I have ordered some charcoal testing kits (which get sent and read by a lab) to use as a kind of reference testing (supposed to be the best way to test apparently) to see which, if either or both, is accurate in detecting radon levels. I will update this review when it does come back, but preliminary testing with the Corentium leaves me unimpressed, especially for the hefty price tag.

Sin problemas con este detector, sólo hay que leer el instructivo porque no da lecturas hasta después de 1 día. No es un dispositivo que responde instantáneamente a los cambios de concentración de Radón, el método de detección requiere su tiempo y lo que se muestra es un promedio.

Buen producto , confiable y las mediciones comparadas con otros equipos lo hacen confiable... recomendado totalmente para medición de gas radón en domicilio