Really not sure I am believing this one. I had my basement professionally tested. It came back with 3.75. I bought the unit as I felt we were a little close and monitoring it seemed like a good idea. It started off very close to the original test results, then after a month or so it gradually increased. I reset it a few times to see if that helped. Tonight though it reads 87.04.... Nothing particularly exciting in the weather. I wonder if the addition of ion generating air cleaners (3 units) has effected it? Added a floor fan as well... I thought all that would only break up the radon molecules.... Crap if I know.

This unit's readings correlate well to recent charcoal mail-in style tests I had completed on my basement.
I used this unit to get a 30 day average prior to a radon mitigation system install to judge effectiveness of the system.
So far I've measured an 86% reduction in the readings; more importantly my basement is now below EPA guideline value.

This unit is certainly pricey but it should save money and hassle in the long run versus the mail-in style tests.
I'm hoping it'll function for several years so I can truly feel like I've gotten my moneys worth - time will tell.
Also, it's nice to always know the exact levels (1-day, 7-day and Long Term) readings in my basement.

One of the best safety products we've bought. It gave the first reading with a few hours and levels become more accurate long term. It gives the current readings along with a short term average which is really helpful. This unit is small and easy to read. Let's you sleep without an alarm going off in the middle of the night. Radon levels can change and this allows you to continuously monitor 24/7 without worry. I would highly recommend buying this monitor. Just peace of mind!

This product has enabled me test and address radon issues. It keeps a 7 day and a 1 day average, alternately, on the bottom and a long term running average on the top. It can be reset and you can check the # of days it's been in service. The one day average allows me to move the unit to the basement or other places in the house and quickly see what the effect is. It actually updates that average every hour so you can put it by a crack and watch the numbers climb hour by hour. People living in high granite areas should buy one if they can afford it.

When I was searching to purchase a home, I generally avoided homes with a Radon mitigation system already installed. I was not well read, informed, or concerned about Radon. I thought that a home with a Radon problem would be devalued in some way. I purchased my home in 2012. The home inspector placed a charcoal radon test kit in the basement. Results returned at 3.8 pCi/L, just under the EPA recommendation of 4.0 pCi/L. I thought great! Remediation is not necessary according to the real estate closing papers. Fast forward a few years, I did some minor basement renovations to remove batt insulation between the exterior rim joists and install a DIY spray foam seal, and replaced my window well windows with dual pane vinyl inserts. I became a little more concerned about Radon now that i "sealed" the basement from drafts. I did a little more reasearch and found that the charcoal kits are statistically very inaccurate. I bought the Corentium unit, because of the great reviews and easy continuous monitoring. The Corentium unit reported long term exposure levels of 8.3 pCi/L. I was surprised the Corentium reported high levels even in the upper floors of my house. That's all the information I needed to contact a Radon mitigation specialist to install a sub-slab depressurization fan to vent the radon outdoors. The mitigation system cost me $1300. The long term levels dropped significantly to below 0.7 pCi/L. The Corentium calibrates itself...just read the instructions, set it down, and check as often as you like. The Corentium is a small investment to buy piece of mind. I highly recommend it. I have loaned the unit to friends, family, and neighbors to help them make informed decisions.