I don't test and probably never will. If I client is adamant about testing during the AR, which I donââ¬â¢t advise doing, I give them the number of one of the big radon testing companies in the area so they can contract directly with them. I think testing during the AR period is silly because of all of the external and internal variances that can skew the short-term results. The only advantage, IMHO, is so the buyer can get the seller to compensate for the remediation, should the number come back high. I advise my clients to hire a radon testing company to do a long term test (6-12 months is my understanding) after they move in, and plan on installing a remediation system regardless of the reading. If radon is bad, which I believe it is, there is no real safe level. I don't trust the EPA or most other government agencies.