I'm just throwing out two OLD (unused) kits, but want to test for radon. Maybe shutting door after horse is out (having lived here for over thirty years), but I still want to know.

For one thing I'm sure any prospective home buyer will want to know.

Are the DIY kits reliable (if you're diligent in following directions)? Not just in term of reliability, but whether the company responds to your kit and whether they are apt to require you
to retest on the grounds of the first test not being analysable for whatever reason (having looked up reviews of two brands I have).

Even if I have to hire a firm not only to test but to remedy it, I'd like to get a notion of what level we may be dealing with. We don't use the basement much, but I'm sure the gas if at a notable level is wafting through the whole house.

Looking for recommendations online, the First Alert kit caught my eye, figuring they're a reliable company overall. What do you all recommend? Have any of you had to deal with radon gas - testing and/or remediation?

Are you testing for yourself, or in preparation for future sale?

I wouldn't bother if it's the latter. In theory, you would have to disclose a positive result and a buyer is very unlikely to accept a negative result based on a DIY test done by the current homeowner. Kind of a lose-lose scenario.

They'll do their own test and hire someone who uses one of the devices that does the most accurate measurements. The companies around here that test usually put one measuring device in the basement, and one on the first level. I think it's a 48 hour test and there are instructions about keeping windows and chimney dampers closed, and closing doors quickly when entering/exiting.

If you're doing it for yourself, I'd only do it if you're prepared to remediate if the readings are high.

A bunch of friends and neighbors have had remediation done, so if you have questions I may know the answers.

I expect prospective buyers are apt to want a retest, but if I can test for under $100 (kit plus analysis) I'd like to know.

For one thing I'm considering renting my small basement efficiency again, largely to have someone to help - if only to be here in emergencies. Don't want to expose an unwary tenant if there's radon. I know that room has small leaks sub-grade.