Are Electronic Radon Monitors Reliable?

In the last few months, I purchased 10 electronic radon monitors from Amazon. Six of these are marketed for homeowners and priced from about $79 to $150. The other 4 monitors are sold as a set, designed for diagnostic testing for radon mitigation contractors. I will go into some more details on comparisons at a later date. But in short for now, what I want you to understand is how unreliable some of these monitors are.

 

The greatest difference in side by side testing was 1.2 pCi/L to 68.7 pCi/L from two of the cheapest monitors. The four new professional monitors, just calibrated from the factory and my other professional testing monitor, at the same time, testing side by side with the cheap "no name" monitors all tested within a tight group of 3.5 to 4.2 pCi/L, which is with in 25% accuracy required by the EPA for a know radon calibration value. I know these test monitors are fairly accurate because I regularly test them side by side with Air Chek certified test kits which are analyzed in a NY State certified laboratory.

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The other cheap monitor had a reading of 42.0 pCi/L. So to summarize, the cheap non brand name, knock off monitors were in no way reliable. 6 of my proven reliable monitors, plus the 4 brand new professional monitors all of which had similar readings with less than 25% difference. I did several of these tests with similar results over a 3 month period.The 3 cheaper monitors were at least somewhat consistent. The first cheap monitor always had readings very close to zero, the second cheap monitor was aways much higher than the professional/reliable monitors with radon readings reported from about 5 to 10 times higher. The third cheap monitor remained in the middle with radon readings reported from about 4 to 6 times higher than the reliable monitors.

 

I will go into more detail at a later date with model names etc. But for now, what I want people to understand is that all radon monitors are not reliable, even though they look very similar, and have what appears to be the same specifications. I also want to note that these cheap monitors I bought were some of the least expensive and new to the market with little or no reviews yet posted. I will do some follow up on these at a later date.

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I'm not going to go into detail here, but another big factor in accurate radon testing is where and how the test is performed. If not placed properly and conducted properly, you will not get accurate results even if using the most accurate radon testing monitor. So be sure to follow proper radon testing protocol. 

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Recommendations:

Two of the radon monitor brands I have experience with that have proven mostly reliable in my use are Air Things and Eco Sense, I also have some reliable experience with Radon Eye also proving to be reliable, even though I do not own that brand personally.