When testing makes sense

Four situations put a radon test on a sensible homeowner’s list.

The house has never been tested. This is most houses, honestly, and the only bad version of this situation is leaving it that way, because no human sense detects radon and a neighbor’s result says nothing about yours. Two foundations a driveway apart can read completely differently.

You remodeled. Finished the basement, converted it to a bedroom or office, added on, touched the foundation. Any of it can change how the house breathes and where people spend their hours. The pre-renovation number is stale.

You’re buying or selling. Transactions test on protocol and deadline, which changes the mechanics enough that radon testing as a service handles it differently than a leisure-time screen.

You have a mitigation system. The retest right after installation proves it worked; periodic retests every couple of years prove it’s still working. The gauge shows suction, but only a test shows a number.

None of this needs urgency theater. Public-health guidance recommends testing because measurement beats assumption. That’s the entire pitch. The test is cheap relative to what it settles, and either answer is useful: a low number buys peace, a high one buys a plan.

How a proper test actually runs

Every legitimate radon test rests on one idea: measure the house the way the house actually holds air.

That’s what closed-house conditions mean in practice. Windows stay shut. Exterior doors open for coming and going, nothing more. Whole-house fans stay off. For short-term tests, those conditions start 12 hours before the device goes live and hold through the whole measurement. You keep living there: cooking, showering, running the furnace all fine. You just don’t wash the house through with outdoor air mid-measurement.

Placement is the other half. The device goes in the lowest level of the home that’s lived in (a finished basement counts, an unused dirt crawl doesn’t), away from drafts, exterior doors, direct sun, and humid rooms like bathrooms. A test on a windowsill in the kitchen produces a number, but not one that means anything.

On devices: the store-bought kit gets a fair word here, because it deserves one. Charcoal canisters and similar kits are legitimate screening when the instructions get followed exactly: placement, exposure window, prompt mailing to the lab. Where they fall short is accountability: no timestamp proving conditions held, no hourly data. That’s why transactions and pre-mitigation confirmations typically use professional continuous monitors, which log the level hour by hour and show whether the test was disturbed.

Retesting has its own rhythm: confirm near-the-line results before spending money, retest after mitigation to verify the fix, and retest every few years as plain good practice.