Could My Radon Monitor Be Broken?

One of the more awkward conversations that I had with a home seller this year dealt with a high radon test at his home in Minnesota.  We performed a radon test for the buyer, and the test came up high (over 4.0 pCi/L), so the buyer asked the seller to install a radon mitigation system.  The seller wasn’t happy about this, so he called us up to complain.

We had performed a radon test for the seller when he bought the home four years ago, and the test was below 4.0 pCi/L.

I could understand the seller’s frustration; I would have been frustrated too.  How could this be?  Was our electronic radon monitor broken?  No, it really just came down to timing.  Radon levels constantly fluctuate throughout the day, and even throughout the year.  There are many factors that affect radon test results – so many that you'll never get the exact same results twice.  A few of the larger factors include:

  • Where the test was placed in the home. 
  • Barometric pressure.  Rainy weather = lower pressure = higher radon levels
  • Ventilation systems.  An HRV running at full speed can cut radon levels in half.
  • Windows open vs closed.  Houses always act like chimneys; warm air rises.  This creates negative pressure in the basement and positive pressure at the upper levels.  When windows are open at the upper levels, the house will act even more like a chimney, which increases radon levels.  That's right; opening windows on the upper levels can actually increase radon levels in the basement, which is where the test is placed.

With all of these factors, why even bother with a short term radon test?  Because it helps to decide whether or not radon is a problem that needs to be dealt with.   The overall seasonal average typically won't be too far off from the short term test.  

I performed a radon test at my own house for 96 hours, and as you can see from the graph below, the levels didn't vary all that much.  The overall average came out to 2.6 pCi/L.  If you were to only look at the highest levels in a 48 hour period for this test, the average would still only be 2.9 pCi/L.  I've performed many tests at my house throughout the year, and the average is consistently between 1 and 3.

Reuben's radon 

For the record, we have every one of our electronic radon monitors calibrated annually.  While radon levels may be volatile, the accuracy of our tests isn't.

Reuben Saltzman, Structure Tech Home Inspections - Email - Minneapolis Home Inspections

Facebook Reuben's LinkedIn Page Follow StructureTech on Twitter ASHI Certified Home Inspector - Click To Verify Click to subscibe to Reuben's Blog

 

 

 

Written By

Reuben is a second-generation home inspector with a passion for his work. He grew up remodeling homes and learning about carpentry since he was old enough to hold a hammer. Reuben grew up thinking he was going to be a school teacher because he enjoyed teaching others so much. In a sense, that’s a lot of what home inspections are about, so Reuben truly does what he loves. Sharlene has worked with Structure Tech since 2000 and Reuben has been contributing to her blog since 2008.

Related Posts

Q&A: should the air exchanger be on or off during a radon test?

đź–¨ Print ArticleWhen conducting a short-term radon test, should the air exchanger be running or not? Great question. I’ve heard it argued both ways. If a home is designed to...

Radon Testing Clowns

the number of unqualified folks conducting radon tests has also increased. Just like home inspections, there are no licensing requirements and no training requirements for radon testing in Minnesota.

Subscribe to Our Newsletter for Market Updates & Mid-Century Modern Listings

Our weekly HomesMSP Update includes current local market information and a curated list of mid-century modern properties for sale, plus posts from an inspector, a lender, a stager, info about neighborhoods, life in the Twin Cities… even recipes!

Hidden

Blog Categories

Archives

Sharon and John Hensrud

About Us

The HomesMSP Team is committed to meeting you where you are and listening… really listening to understand you so we can use our extensive knowledge of the market and local neighborhoods to give you personalized service.