Which radon test kit should you buy?
For a first check, a short-term charcoal kit (2 to 4 days) is the cheapest way to get a number. For your real year-round average, use a long-term alpha track kit (at least 91 days). A digital radon monitor costs more but shows readings continuously, which is useful after a mitigation system goes in. Whatever you buy, it should be analyzed by, or certified through, a recognized radon proficiency program.
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Which kit do you need?
| Your situation | Best kit | Why |
|---|---|---|
| Never tested, want a quick answer | Short-term charcoal kit | Cheapest. A few days of testing plus mailing time |
| Short-term result between 2 and 8 | Long-term alpha track kit | Tells you the year-round average before you spend on a fix1 |
| First result over 8 | Second short-term kit, right away | Wisconsin DHS advises a quick retest at this level1 |
| Just had a system installed | Short-term kit, then a monitor | Confirms the fix and keeps watching |
| Buying or selling a home | A certified tester, not a DIY kit | Documented, tamper-resistant results |
What to look for in a test kit
- Lab analysis included. The price should cover the lab fee. Prepaid return postage is a plus.
- A certified lab. Look for analysis by a lab listed with a national radon proficiency program (NRPP or NRSB).
- Clear dates. Kits have an expiration date and a window for mailing back. A kit that sits too long gives a bad result.
- Instructions you'll follow. Closed house for 12 hours before the test, lowest lived-in level, 2 to 7 feet above the floor.1
What to look for in a digital monitor
- Long-term and short-term averages on the display, not just a live number.
- A known accuracy spec from the manufacturer, and ideally independent testing.
- Data you can export if you want to show a buyer or mitigator the trend.
A monitor is a tracking tool. If it shows high readings, confirm with a lab-analyzed test before paying for a fix.
Where to get a kit
Hardware stores and online retailers sell lab-analyzed kits. Many state radon programs also offer free or low-cost kits, especially in January, which is National Radon Action Month. Your state's page links to its radon office.
Read your result
The EPA recommends fixing your home at 4 pCi/L or higher, and considering it between 2 and 4.2
How we choose products
We haven't hands-on tested specific radon kits or monitors yet, so this page explains how to choose rather than ranking brands. When we recommend specific products, we'll say how we tested them, and links that earn us a commission will be labeled.
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Common questions
Are home radon test kits accurate?
Lab-analyzed kits are reliable when you follow the placement and closed-house instructions exactly. Most bad results come from setup mistakes: wrong room, open windows, or a late mailing.
Are digital radon monitors as good as lab kits?
They're great for watching trends and checking a mitigation system, but consumer monitors are not a substitute for a certified test in a home sale. Let them run several days before trusting the number.
Do radon test kits include lab fees?
Many do, but not all. Check the box for 'lab fee included' and whether return postage is prepaid.
Where can I get a free radon test kit?
Some state radon programs give out free or discounted kits, often during National Radon Action Month in January. Check your state radon office.
Sources
- Radon: testing your home Wisconsin Department of Health Services
- What is EPA's Action Level for Radon and What Does it Mean? US EPA