What is the highest radon measurement you have seen? I had one today that measured 41.7.
The second highest was somewhere in the 60’s
And I thought mine was high!
I had one once that measured at 94.0, thought it was junk so we retested and came back at 89.0.
I thought mine was high at 37.
In Custer SD we routinely get readings in the 150 to 300 range. I quit using short term electrets there and use the long term electrets in the short term chambers. Otherwise you just burn up a good set of electrets. In recent years the highest I’ve seen were 545 in Custer, 935 in an area in Rapid City and one in Hot Springs SD at just over 1000. And we still don’t have a state radon program.