I've been told that the accuracy of the self test kits is + or - 25% if used properly. Which would mean if the test kit was used properly, your levels are high enough that it would call for radon mitigation. Who placed the kit? Was it done properly? If you're unsure, I think you're right in asking a certified radon inspector to re inspect.

Radon was detected in a home we were purchasing in Denver back in 1989 -- they sealed all the edges of the basement with some type of caulk stuff, sealed the crawlspace under the garage by putting a sheet of plastic down and vented the crawlspace to the outside with a fan. I can't tell you the cost of it because the seller paid for it, but I really don't think it was that costly. Two years later when we sold the home and it was again tested for radon, it was within acceptable limits, so whatever the mitigation company did worked.

Radon mitigation systems are not terribly expensive to install. Depending on the size of your home and the access in your basement, most systems are not more than $1500. If the buyer is willing to split with you, its a simple fix.

Before I took any decisive action, I think I'd want a certified inspector. A home kit doesn't sound too trustworthy to me.

You don't mention what state you live in...but in NJ, in order for a radon test to be valid for the purpose of a RE transaction, the test must be performed by a licensed radon technician. If it is so much a moved by anyone else, the test is invalidated. Your state may have the same requirement...it is worth checking.

The test itself is not as simple as it may sound...proper placement of the testing device can be complex..depending upon the house itself. There is no way to know for certain if the buyers followed proper protocol.

Personally, I would not consider any test result as valid unless it was conducted by a certified and/or licensed radon technician.

I had radon in my home as well. It was tsted first with a canister kit - similar to what you describe. I then was tested continuously using professional grade test equipnment. The two results were comparable. You may as well move forward to remediation. Yes - $1,500 will probably take care of it.

Our radon inspector found radon in the house we bought last July. The sellers had agreed in advance to mitigate radon if it tested high. It did, and they paid for the mitigation system. I think it was about $1200. The inspector tested again after the system was installed and the levels were more in line with EPA standards. I wouldn't trust a self-test kit. Sounds fishy to me.

If anything, I'd think a self-test kit would yield too low of a reading, not too high. Thus, if you're at 9.1 at a self-kit, any "better" kit might be more sensitive and yield a high reading. I would think the cheaper canisters would be less sensitive. That being said, this is all my opinion, based upon zero scientific fact, for what it's worth.

Also, the problems with radon readings is that they fluctuate over time, depending on a host of factors such as season, wetness of the surrounding ground, pressure in the house, windows opened/doors opened, etc. So, while a $100 inspector might come up with a different result, it might not be due to the quality of the testing, but changed conditions.

I have used both. I got comparable readings.

The buyer paid for the first test, didn't he? If YOU want a re-test, shouldn't you pay for it yourself? In my experience, the remediation systems are generally not too pricey. Ours was about $1000.

The buyers have triplets they plan to have sleep in the finished basement. I can understand her concern over radon. I'd do another do-it-yourself test, but it takes 7-10 days before the results are analyzed and made available.

We've decided to go ahead and split the cost of remediating. Hopefully, from what I've read, no more than $1,000 total for the job. It will be nice to finalize the transaction!

rmo87: "The buyers have triplets they plan to have sleep in the finished basement"

Please tell me that there is a proper means of exit in case of fire..such as a door directly to the outside...or a window low enough and large enough to access and climb out...

I wouldn't trust a $15 radon test done by the seller. Who knows if they properly sealed the space up for the test? They're not motivated to do it correctly and risk a high reading.

In past real estate transactions, I've always paid for the test myself. And had it done by a certified inspector.