How do I calibrate my radon monitor?
Homeowner grade continuous radon monitors or hCRMs for short are becoming increasingly commonplace. AirThings, Safety Siren, and Ecosense are some of the major manufacturers. These devices can be found online for less than $150 and some rival the accuracy of professional grade devices that are five to ten times the price. However, one thing the manufacturers don’t come right out and tell you: hCRMs cannot be recalibrated*. Most come with a standard one-year warranty. What happens when that device “goes out of whack”? The answer is we don’t know.
hCRMs are relatively new advancements in technology. Ten years ago, devices with the accuracy of EcoSense’s EcoQube cost over $5,000! Professional-grade CRMs are often $750 or more. What makes these so much more expensive if the accuracy is similar? Calibration.
Pro-grade devices must be recertified at least once every two years. Certification takes place at a national laboratory like Bowser-Morner or KSU. Calibration can cost upwards of $200. Why would someone pay $200 to calibrate an hCRM that can be bought new for $150? The answer is: they don’t–which is why these services aren’t offered.
I’m writing this blog post to raise awareness on this troubling disparity. That monitor you bought on Amazon may “go out of whack” one day, and if you don’t keep it honest, you won’t know.
Below is my totally-not-certified technique for how to keep your hCRM honest. The surefire way to make sure your radon system is working is to have an NRPP certified professional test and service your system every two years as recommended by the US EPA.
Here’s what I do. Every winter, I get a short term test kit and place it next to my hCRM. Then I take a screenshot of the app average–or a photo of the device display during the testing period. A few days later, when I get the lab results from my mail-in test kit, I simply compare the results. If my hCRM ever shows a drastically different number than the lab kit, then know it’s time for a replacement**.
Perhaps one day radon monitor manufacturers will offer a leasing or rental service to ensure hCRMs stay accurate and stay out of the landfill. Let this be my call to all manufacturers, we want sustainable products!
PDS recommends EcoSense devices for their accuracy and customer service. PDS price matches EcoSense devices so if you see a lower price on Amazon, call us and we’ll match it! Choose the EcoBlu if you don’t want any more smartphone apps—the EcoQube is for the technophiles among us with wifi and smartphone app connectivity.
*at the time of publication there is no known hCRM recalibration program to the author. Please email me if you have a program and I will edit this post
**at the time of publication, Brent’s three-year-old EcoQube is still going strong!