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Radon Test Kit vs. Professional Inspection

Radon measurment in progress

If you are a regular reader to this website, I think you understand the importance of radon testing.  It is a serious health issue and the second leading cause of lung cancer. “Should you have radon testing done?” is not the question per se; that is obvious.  But for many, the next logical question becomes “How should we perform radon testing?”.    Let’s compare a radon test kit with a professional inspection.

If you venture to any hardware store, you may find a DIY radon test kit that you can purchase rather inexpensively.  Is this the route to go? Do you really need to hire a professional radon tester? 

Call me biased, but for most scenarios, I would recommend a professional radon expert with the appropriate credentials.  If I were asked “why you should hire an expert?”, I would answer in three words – “peace of mind”. Let me explain.

The difference between radon test kits and professionals?  

Professionals will typically use “time-integrated” sampling with electrets or continuous radon monitors (CRMs).  These types of testing are performed over a certain time period which can be anywhere from 2 days (minimum) to more than a year.  These results provide a measurement of the average level of radon during that time period. Do-it-yourself kits are not time-integrated and may not be as accurate.

Can a DIY test kit work just as well?  Sometimes, it depends on the reason for the test.  If you are curious about the level of radon in your basement, a radon kit might be a good first step in figuring out if there is a potential problem.  But beware! There are potential downfalls.  

What could go wrong?

Often times the accuracy of the DIY test can be uncertain because, let’s face it, it is being performed by amateurs.  The instructions for the test kit need to be followed very closely. Doors and windows need to be closed at a minimum of 12 hours prior to the test and during the entire testing period.  You should not attempt the testing during wind or rainstorms which could possibly give an unusually high radon reading. The “do it yourself” kits are often times charcoal tests and can be very sensitive to humidity.  

The location of the test is also key.  The test should be conducted at the lowest living level, but not in crawl spaces.  Testing should not occur by sump pumps, kitchens or bathrooms. Placing a tester in the wrong location can give you a false positive and needlessly give you a false alarm.  

After the test is performed, you need to send it to a lab where you would wait for weeks to get the results.  That is unacceptable for almost any real estate transaction.

Benefits of having a professional test!

The professional has the certification and training to ensure that radon testing is done correctly.  When testing with electrets, a technician can test in multiple areas of a home. This can be a great aid in helping a mitigation company install a radon system.  An expert can also use a CRM test to determine if weather systems or humidity influenced the radon levels in the home. Both of these devices are only used by someone who is licensed and uses quality assurance plans on all of their equipment.  

Radon professionals are required by the state to regularly calibrate their equipment and work to ensure accuracy and precision in the testing process.   Also, if time is of the essence (and in real transactions, it usually is!) you don’t need to ship the kit off to a lab. You can get the results within a day by using a local professional.


When contemplating how to perform a radon test, there is nothing technically wrong with using a test kit to see if there is a problem.  But again, beware! There are many ways that the testing process and results can easily throw the measurements off in the home kit. A licensed expert can greatly enhance the accuracy of measuring the levels and provide those three key words “Peace of mind!”.

For further information, we recommend checking out the EPA’s website regarding both of these options1.

  1. https://www.epa.gov/radon/find-radon-test-kit-or-measurement-and-mitigation-professional#who

Ian Cull

Ian Cull is a nationally recognized expert in the field of indoor air quality. He is the Chief Science Officer of Indoor Science, a company he started in 2004. He speaks around the world on air quality topics and is a training provider of the Indoor Air Quality Association. Mr. Cull is a Licensed Professional Engineer (PE) and Certified Industrial Hygienist (CIH). His degree is in Environmental Engineering from the University of Illinois - Urbana Champaign. Mr. Cull has developed 50 air quality related courses for the IAQA University and is the author of the book, “Fundamentals of Mold Remediation”. In his words… “Besides being passionate about indoor air quality, I enjoy cycling, music, the Chicago Bulls, and having fun with my three kids.”

One thought on “Radon Test Kit vs. Professional Inspection

    I like how you mentioned that DIY radon test kits could be inaccurate due to amateurs performing the tests. My brother is thinking of looking for a radon and water testing service because he’s considering buying an older home in the city and wants to ensure everything is safe to use in the house. It seems like a good idea for my brother to think about hiring a reputable professional to help him test for poisonous substances in the home he wants to purchase so that he and his family can stay healthy.