A radon test kit can give you a useful first measure of the gas in your home—but the result depends on where and how long you test. For a picture of your usual exposure, test a room on the lowest level you regularly use and, where practical, measure for at least three months. Then compare the result with your country or region’s current guidance, not a threshold found online for somewhere else.
Where To Place A Radon Test Kit
Radon enters buildings from the ground through openings such as cracks and gaps around pipes. Levels are often higher in basements, cellars and rooms in contact with the ground, though high concentrations can also occur above ground level. Levels can differ between neighbouring homes and from room to room, so a nearby property’s result cannot tell you what is in yours.
Choose the lowest room that you or your household use regularly. If the basement is unfinished and rarely occupied, a regularly used room on the ground floor may better reflect the air you breathe. If you use a basement as living space, it may be the relevant place to test. Follow the kit’s instructions for positioning the detector and for keeping the room under the required conditions during the test. National testing protocols matter too: the World Health Organization (WHO) says measurements should follow national protocols to support reliable decisions.
How Long Does A Radon Test Take?
Radon varies over time, so a brief test is a snapshot, not necessarily a reliable estimate of your annual average. WHO recommends measuring for at least three months to estimate that average. A longer test is especially useful when you want to understand typical exposure rather than make a time-sensitive decision.
Guidance is not identical everywhere. WHO says short-term tests can be useful for time-sensitive situations, such as a home sale or checking whether mitigation worked. In a 2022 Monte Carlo analysis, Andrey Tsapalov and Konstantin Kovler compared short- and long-term testing using simulated samples of buildings. They concluded that, for estimating collective risk across buildings, how representative the sample was mattered more than test duration. That modelling result concerns population-level assessment; it does not show that a short test estimates an individual home’s annual average as well as a long one. Their paper also describes short tests of two to seven days as common in the United States and longer testing as preferred in European guidance. Follow the protocol where you live and choose a duration suited to your decision.
How To Interpret Radon Levels
Check the units on your result and compare it with the current action or reference level set by your local authority. Radon concentrations are commonly reported in becquerels per cubic metre (Bq/m³); some US reports use picocuries per litre (pCi/L). Don’t compare the number alone if the units or test duration differ.
There is no single action threshold used everywhere. WHO recommends a national reference level no higher than 300 Bq/m³, and the EU framework cited in indoor-radon research also sets 300 Bq/m³ as an upper reference level. National reference levels commonly range from 100 to 300 Bq/m³. These figures are not a universal definition of a “safe” home or a substitute for local rules. Check your national or regional radiation-protection or public-health authority for the relevant threshold and what follow-up it recommends. If a short test is above that level—or close enough that the result is hard to interpret—ask whether a longer or confirmatory test is appropriate under local guidance.
What To Do If A Result Is High
Share the test report and its dates with your landlord or a qualified radon professional. Ask what the result means under local guidance, whether another test is needed, what mitigation options suit the building, and how effectiveness will be checked afterward. If you rent, keep a copy of the result and ask for a written plan and timeline; tenancy requirements vary by location.
WHO describes passive mitigation systems and says they can reduce indoor radon by more than 50%; adding ventilation fans can reduce levels further. That is not a guaranteed result for every home. A qualified professional can advise whether a passive system, a fan or another approach is suitable for your property, and arrange a post-mitigation test. If you have questions about personal health risks, speak with a clinician; the home test measures radon, not your individual health risk.
