Airthings Corentium Home Radon Detector 223 Portable, Lightweight, Easy-to-Use, (3) AAA Battery Operated, USA Version, pCi/L
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Arrives
Friday, Oct 23
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Style: Original
Features
- FIRST OF ITS KIND: The first battery-operated, digital radon detector. Monitor your home without the need for an outlet.
- LONG TERM MONITORING: Monitor for cancer-causing radon gas. Long term monitoring is necessary as radon levels fluctuate daily.
- BE IN CONTROL: Take action if your radon levels are high. Know if your improvements have worked by checking the short term, on-screen readings.
- RADON REPORT: Generate a radon self-inspection report easily, whenever you need it.
- FAST RESULTS: On-screen results show both long and short term readings, for a quick overview of your radon levels.
Description
The Corentium Home by Airthings radon detector is a state-of-the-art measuring instrument that combines ease of use and performance. The Corentium Home by Airthings radon gas detector allows you to take a reading of the radon levels and its LCD screen displays the average daily, weekly and long term concentrations. Powered by 3 standard AAA batteries, the radon monitor makes it easy to take measurements from one room to another in order to get an overview of the concentrations of radon in a home, workplace, school, a daycare centre or any other location. The Corentium Home by Airthings radon detector is also an essential tool to use when performing property inspections or when checking the operation of a radon mitigation system. The internal architecture of the Corentium Home by Airthings radon monitor comes from advanced technology normally reserved for commercial-type detectors. Particular attention has been paid to the quality and protection of the internal components, allowing the use of algorithms for signal analysis that are more sophisticated. The Corentium Home by Airthings radon gas detector quickly adapts to its environment and eliminates inaccuracies related to external factors, allowing it to obtain the best accuracy in its niche. it requires no annual calibrations throughout its useful life, estimated at over 10 years.
Brand: Airthings
Style: Original
Power Source: Battery Powered
Color: black
Product Dimensions: 1"D x 2.7"W x 4.7"H
Item Weight: 3.52 ounces
Operating Humidity: 95 percent
Upper Temperature Rating: 104 °F
Sensor Type: radon detector
Global Trade Identification Number: 19, 34
Brand: Airthings
Model Number: 223
Global Trade Identification Number: 19, 34
Manufacturer Warranty Description: Airthings has a 5-year extended warranty available on all air quality monitors for consumers. Registration is required within 30 days of the purchase on the Airthings website. Registration is free and your statutory rights are not affected.
Unit Count: 1 Count
Number of Items: 1
Manufacturer: Airthings
UPC: 854232008019
Built-In Media: Radon sensor, 3 AAA batteries
Item Type Name: Corentium Home Radon Detector
Mfr Part Number: 223
Power Source: Battery Powered
Sensor Type: radon detector
Operating Humidity: 95 percent
Upper Temperature Rating: 104 °F
Product Style: Original
Color: black
Item Dimensions D x W x H: 1"D x 2.7"W x 4.7"H
Item Weight: 3.52 ounces
Enclosure Material: ABS
Frequently asked questions
If you place your order now, the estimated arrival date for this product is:
Friday, Oct 23
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View our full returns policy here.
To initiate a return, please visit our Returns Center.
View our full returns policy here.
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Top Amazon Reviews
Style: Original
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.
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Reviewed in the United States on October 4, 2023 by the weathered man
Style: Original
The Corentium 223 should be in every home where Radon is a concern! Several years ago, I had a sub-slab depressurization system installed after a charcoal test measured 7 pCi/L. At the time, two follow up charcoal tests came back at 3.4 and 2.3 pCi/L so I felt better but for the past few years, I've still wondered what a longer term test would show. For peace of mind, I purchased the Corentium 223 and I have since learned so much about how Radon levels vary given the weather and how a charcoal test, while accurate, is going to only tell you so much. I've had the Corentium 223 set up in my basement for the past 3 months in mostly closed house conditions and found my long term average to be 1.76 pCi/L, but the daily average was as high as 8.3 pCi/L! The more rain fall in the past 24 hours, the higher the Radon level in the basement. On clear sunny calm days, the levels dropped to around 1 pCi/L. There are a lot of sites that talk about how Radon levels vary depending on the weather, but I've never found any site that details exactly how the levels increase by rainfall. This could be unique to my property, but the correlation has been eye opening. Hoping I could improve the effectiveness of the mitigation system, I decided to seal the crack between the wall and floor next to the suction pipe by adding silicone along that wall to seal the joint. (I've seen several sites suggest this and I could hear a slight hissing with the air leaking so figured I'd give it a try to see if there was any change.) The next day, the 1 day average was just 0.10 pCi/L! The following week, the 7day average dropped to 0.71 pCi/L, even after one day of heavy rain that week!!! Another concern I have had is the amount of Radon in my water. I have a private well and have considered having the water tested, although research I have read on the topic indicate almost all water from private wells will contain Radon, but the danger is really the amount of Radon that you breath in, not consume. While the Corentium 223 only measures the amount of Radon in the air, it will measure the amount of Radon in the house that is given off by water use in the house such as showering and doing laundry. My concern was that I have a whole house humidifier that runs occasionally in the winter months and uses water from the well. While I do see a slight increase in Radon in the house when the humidifier is running, it only seems to be 1 - 1.5 pCi/L increase and it is hard to say if it is really from the humidifier or just natural fluctuations. I have yet to read any warnings on the EPA site or other sites about the hazards of increased Radon exposure when using a whole house humidifier on a private well, but this monitor was able to help put my mind at ease on the issue. If you really want to know the Radon levels in your home, and measure effects of various mitigation strategies, this is the only device I've found on the market that will give you immediate, reliable and accurate data. After 24 hours of powering on, you have your first readings and after 7 days you have your first long term average. It is simple in the design and implementation and the quality of construction is superb. I should also mention that I ordered the Safety Siren Pro Series3 Radon Gas Detector - HS71512 by Family Safety Products, Inc., but the device I received wouldn't power on. I returned it the next day and purchased the Corentium 223. There is no comparison between the quality of construction between the two devices and with annual calibration requirements of the Safety Siren, the price for the Corentium for 10+ years of use is an easy sell. The device has a micro USB port on the side. My only wish is that there was support for downloading of Radon readings to a computer. Being able to download historical readings would allow for graphing and comparison to local weather reports. If it did this, I'd give it 10 stars! I would highly recommend the Corentium 223 if you have had 2 charcoal tests with results >4.0 pCi/L. In my mind, the Corentium 223 is the absolute best digital Radon monitoring device on the market today!
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Reviewed in the United States on January 16, 2016 by JDMac
Style: Original
“Since WHEN do you smoke?!?!” I yelled, overcome with emotion. “I know that you’re smarter than that!” That was a lie. He’s dumb as a sack of sand, but I try to be encouraging. My dog Roofie (the neighbor kid named him and I adopted him when the neighbor kid’s parents decided that running from their obligations and responsibilities was a more viable option than nutting up), just rolled his eyes up at me, looking sad and sorry. “It’s not his fault.” Said the Vet. “The number one cause of lung cancer in dogs is radon gas. I’ll bet your home has gas seeping up from the basement and it fills your house. You’re probably in danger too and should get checked, just to be sure.” I was stunned. Roofie looked at me like I owed him an apology. So there was doggy surgery and chemo. I was glad that the chemo wasn’t in some cutesy “pet friendly” packaging. I was boiling mad about the radon. This detector immediately confirmed that the vet was spot on. I got the abatement team in and they quickly installed the proper suck and blow gear to rid my home of the invisible killer. The machine is A+ accurate (the pros didn’t even bother testing when they saw my detector, saying it was as good as good can be). Easy to use, conveniently sized, well built and long battery life all make this a great buy.
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Reviewed in the United States on June 26, 2026 by Dean Winchester
Style: Original
We have purchased 3 of these Airthings detectors, plus several of another brand that provides only long term average readings. Our house has 3 separately poured slabs plus a crawl space, leading to potentially complex and expensive remediation proposals. Seasonally, areas of the house seemed to be sitting about at the EPA limit based on one-time mail-in tests and we really felt we did not understand what the actual sources were. So we had trouble evaluating both the radon risk and the likely efficacy of contractor remediation proposals. Things we learned (or confirmed) about our radon problems with the help of the Airthings sensors: * Radon levels fluctuated significantly (like up/down by a factor of 3 to 4X) day to day based on weather, season, and other factors we couldn’t identify. * Certain areas of the house living space had consistently higher radon levels than others. * “Obvious” sources were not necessarily actual sources. Crawl space was bad, but the drainage sump was not, for example. We also learned some things about the Airthings sensors which were not ideal: * Two units side by side can give very different short term (4 hour and 7 day) readings. Like 20 – 30% different. The long term averages do seem to converge over time (multiple months) to within a percent or so. * A contributing issue we had were drainage problems, leading to some wet areas. The Airthings sensors were sensitive to humidity and did not work in humid situations (this is documented in the user guide). One failure behavior though is that the Airthings sensor will give a “0.000” reading when exposed to high humidity and then even when moved to a drier location, will give subsequent inaccurate low readings. Doing a hard reset by removing the batteries seemed to fix them. One star off for this limitation. In the end, we were pretty happy with the product, given that we bought 3 of them. Things we liked: * Very easy to use, basically just put in the batteries and go. And those batteries last a long time (years). * The short term readings (4 hour and 1 week averages), while probably not super accurate, without a doubt give good information on relative radon levels and trends. The quick feedback and response we found helpful. * Based on convergence of the long term readings between units, those are likely accurate. And this is what professionals say you should care about, rather than day to day fluctuations. * Price is very reasonable considering the use we have made of them. It would have taken hundreds of mail-in tests (at $30 a pop) to do the investigations and monitoring that we have done with our Airthings sensors. Having a continuously reading sensor that could be moved around let us answer our questions about variations in home radon levels. We’ve since had a remediation done which has dramatically lowered the home radon level. But with the Airthings sensors, we can see that there are still hot spots that will allow fine tuning of the solution to get further improvement.
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Reviewed in the United States on December 28, 2020 by R. Taylor
Style: Original
[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 Safety Siren Pro Series3 Radon Gas Detector - HS71512 by Family Safety Products, Inc. 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.
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Reviewed in the United States on April 5, 2014 by Impetigo
Style: Original
I am a retired chemist so I’m concerned about radon emissions. I had absolutely no knowledge of this product or company until I found out that have a lot of radon in my new home. So, I purchased a model 223 a couple weeks ago and am using it to help me understand the situation while I wait for remediation. It’s doing a wonderful job of informing me of ‘hot spots’ and the average level throughout the house while I hold my breath. Now to its accuracy. The Corentium 223 specification is perhaps the most honest approach to accuracy I have ever seen in a consumer product. It’s based on: ‘sigma = less than [a percentage and the length of test]. It is statistical probability specification of accuracy and it is rich in accuracy information. However, you need to do the math, understand what ‘sigma’ means in variance statistics, understand probability distribution curves, and then the use the spec to calculate the worst case accuracy of the device associated with your own radon situation). So, please do that before you criticize the device. If you studied the specification and did the math, as I have, you would see that it is quite accurate for an inexpensive radon continuous monitoring device.... and way more than suitable for home use. Let me repeat that again. If you use the device as instructed by the manufacturer and are willing to trust the specification as determined by some very smart people who spent a lot of time, money and brainpower to prepare it, then you will be measuring Radon and its variability in your home in a way that is vastly superior to doing periodic mail away tests. The radon in your home varies from day to day, month to month, hour to hour. The anecdotal ‘evidence of accuracy’ presented in virtually all of these reviews is absolutely without merit. Why, because determining the accuracy of the device against a standard source is extremely complicated. As a chemist I know that for a fact. We, as customers, do not have the time, money, equipment, or knowledge to do it - period. If you are somehow guessing that you need better accuracy in a shorter period of testing then please consider buying the Corentium pro for $1200 or perhaps some other professional device. You may not get better accuracy but you will likely get equivalent accuracy in a shorter period of time.... that’s how the statistics work. Please read the last two sentences again. Consider this too. The manufacturer, Air Things, is based in Europe and it appears to be a spin off of CERN in Geneva, Switzerland. Look up CERN in Wiki. You will be impressed. They are the world’s leading experts on making and measuring radiation. I am impressed because their ‘no calibration necessary’ technology for this device (and their more expensive professional models) seems to be the result of a micro miniaturized, more precise spectroscopic technology for measuring radioactive decay of radon daughters alpha particle emissions. Finally, I’ve read literally hundreds of these Amazon reviews where accuracy is mentioned... and actually is somehow mysteriously determined in the basement of their home. However, I’ve not seen one review that references the manufacturer’s specification. Everyone here that’s comparing ‘this to that’ or ‘that to this’ and making claims about ‘accuracy’ doesn’t have a clue what they are talking about. However, a number of thoughtful reviewers seem to have run side by side tests with other devices or mail away canisters. Assuming those tests were done properly, then they can be considered slightly helpful but otherwise of no use in determining the device’s accuracy. I’m going by the specification. I’m confident in my device and am very relieved that I own one. —- UPDATE: April 28, 2021 I bought a second unit a couple months after purchasing the first, so both are now over two years old. I am very happy with both units. No problems - I lent one out to my daughter for a few months. Now I keep one in the basement and the other on the first floor. I recently replaced the batteries in the first unit (a two year battery life - just like the manufacturer said) and have had no problems at all with either unit. Regarding Accuracy - I am reiterating that the Airthings accuracy specifications (which result from the highly advanced ‘spectroscopic’ technology behind it) are extraordinary for a low priced unit. Don’t believe the misinformation from reviewers here who claim to have determined the ‘accuracy’ of their Airthings unit as bad or good by running some kind of ‘test’. You/ Me / Other Reviewers / cannot in any way determine the accuracy of any type of radon device or test kit on the market - not for any device - not for any manufacturer). Period. The only choice you have for determining the accuracy of any device you buy is to trust the manufacturer, the manufacturer’s statistical process control, and that the manufacturer truly, deeply understands the extremely complex issues in radon measurement. The Airthings company was founded by CERN scientists. CERN is where many of the smartest on this planet create and measure radiation with the Large Hadron Collider (LHC). So... I trust the Airthings accuracy specification. So - If you really want to know the accuracy of any type of any radon monitoring detector you purchase (regardless of the manufacturer), here is what I would recommend so as to get decent accuracy results. - identify an analytical laboratory highly specialized and experienced in the many complexities of radon measurement - ensure that it is a laboratory using standards and equipment based on measuring radon in the atomic form(s) in which it is most carcinogenic, - send them your device and have it tested under tightly controlled laboratory conditions for a period of time (that is dependent on the rate at which that particular device model approaches the true radon value). For me, buying two of the Airthings devices was an easy decision once I researched and understood the issues in Radon measurement, and the various devices available. As I said previously, I have no affiliation of any kind with this company, but I do get frustrated when reviewers who have no clue what they are talking about provide horrible misinformation for the rest of us.
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Reviewed in the United States on February 9, 2019 by tenor1
Style: Original
For the price this device is great. The batteries last a long time. Information is given on the unit itself. Readings were compared to a professional unit when we had mitigation installed in a new dwelling and this unit was accurate. Screen is starting to fade after almost 10 years. Was looking at the Ecosense RD200 RadonEye, but that one is not battery operated, the on screen display only show current reading, it uses bluetooth with an app. to get more than current reading. People have issues with the app and/or bluetooth connectivity. Seems I will be purchasing another one of these, as it overall seems far superior to the RadonEye. I dont want to have to plug it in, I do not want to install an app. Thank you Air Things, for creating a simple and effective device.
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Reviewed in the United States on May 11, 2026 by Amazon Customer
Style: Original
Biggest benefit: This device permits observing units of radon going up and down on a 24-hour rolling average. (It also displays a 7-day rolling average and the Average-Since-Reset.) This permits comparing different weather conditions, different floors of the house, different distances above the floors, and different amounts of ventilation. Because it is portable and battery-powered, it can go to any location to make comparisons. Using this unit, we found out that: 1) changing weather conditions can easily triple the reading or reduce it to one-third; 2) The second floor of the house has nearly zero radon, the ground floor has a very small amount, and the basement has the most; 3) distance to the floor makes a huge difference since the radon molecule is 8-times heavier than air; 4) a simple and cheap duct fan sucking near the basement floor and exhausting out a basement window dropped all the readings to a negligible level and has kept them there for half a year so far! We even learned that when nearby farmers apply phosphorus fertilizers we can detect it with this unit (phosphorus fertilizers contribute small amounts of background radiation). None of this would have been possible with a one-shot mail-in long-average test, so this unit is a perpetual money-saver and very educational! Biggest frustration: It is too bad that the rolling average can't be for a shorter time than 24 hours. It would be very interesting to be able to see a rolling average for 12-hours or even 1-hour. We can only surmise that the manufacturer doesn't want people to panic, since readings really do fluctuate way more than a person would think. For instance, when a big high-pressure fair-weather front moves through, gases are pushed into the ground, but when a low-pressure storm front moves through, gases come up out of the ground. (The earth "breathes.") From writing down the 24-hour rolling averages (updated every hour), one can deduce the hour-by-hour fluctuations and even work backwards mathematically to calculate hourly fluctuations if desired, using an easy-to-make Excel spreadsheet. All in all, why pay $20 to $50 for a one-shot long-average mail-in test, when with this unit you can take dozens of readings all over the house and with changing weather and ventilation, and keep doing hundreds of readings for many years to come?
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Reviewed in the United States on July 31, 2018 by E&A