Best Radon Test Kits in 2026: Short-Term, Long-Term, and Digital Monitors

By Radon 101 · Last updated June 19, 2026

Start here: free and low-cost kits

Spending money is often unnecessary for a first test. Many U.S. state radon programs and local health departments hand out free or heavily discounted kits, especially during cooler months when indoor radon tends to peak. The American Lung Association partners with several states (Pennsylvania, Iowa, Connecticut, and others) to mail subsidized kits, and some county health departments stock them year-round.

To find one, search your state name plus “radon program” or call your state radiation control office. Kansas State University runs the National Radon Program Services hotline (1-800-767-7236), which can point you to local options. In Canada, Health Canada and several provinces run periodic low-cost kit campaigns through groups like Take Action on Radon.

These program kits are usually the same charcoal canisters or alpha-track devices you would buy retail, with the lab analysis already covered. If a free kit is available, use it first. You can always buy a monitor later if you want ongoing data.

For the full step-by-step, see how to test your home for radon.

The three kinds of radon tests

There is no single “best” device, only the right one for your situation. Tests fall into three groups.

Short-term charcoal (activated-carbon) kits sit out for 2 to 7 days, then go to a lab by mail. The carbon adsorbs radon while exposed, and the lab measures it. These are cheap, simple, and the standard for quick screening and real estate transactions.

Long-term alpha-track kits stay in place for 90 days to a year. A small piece of plastic records tiny etch marks from alpha particles, which the lab counts. Because radon swings with weather and season, a long-term test gives a far more representative annual average.

Continuous digital monitors are electronic devices that sample the air constantly and show readings on a screen or app. No lab, no mailing, no recurring fee after purchase. They are ideal if you want to see how radon responds to weather, ventilation, or a mitigation system.

How to test correctly

A bad test gives a misleading number, so the method matters as much as the device. The EPA’s guidance is consistent across kit types:

• Test the lowest lived-in level. That usually means a finished basement, or the main floor if the basement is unfinished and unused.
• Use closed-house conditions. Keep windows and exterior doors shut (normal in-and-out is fine) for at least 12 hours before a short-term test and throughout it. Open windows dilute radon and hide the real level.
• Place the device away from drafts. Keep it 20 inches or more off the floor, away from exterior walls, vents, fans, fireplaces, and direct sun, and at least a few feet from windows and doors.
• Avoid testing in storms or high winds when possible, since extreme weather skews short-term results.

If a short-term test reads 4 pCi/L or higher, the EPA recommends a follow-up test (a second short-term or a long-term) to confirm before you spend on mitigation.

Watch the lab fees

The single most common surprise with charcoal and alpha-track kits is the lab fee. Some retail kits look cheap on the shelf but charge a separate analysis fee when you mail them in, sometimes more than the kit itself. Always confirm the listed price “includes lab fees” before buying. Digital monitors have no lab fee, but they cost more upfront. Over several years of monitoring, a one-time monitor can be cheaper than repeated mail-in tests.

Best short-term mail-in kits

Use these for a fast screening or a real estate transaction. Choose a lab accredited under the AARST-NRPP or NRSB programs so the result is defensible.

First Alert RD1 Radon Gas Test Kit. A widely stocked charcoal kit, often around 15 to 20 dollars with lab fees included and results in a few business days. Pros: inexpensive, easy to find, lab fee bundled. Cons: short window catches only a snapshot; single-use. Check price on Amazon

AccuStar / AirChek (Spruce Environmental) charcoal kits. Long-running mail-in kits processed by an accredited lab, frequently used by inspectors and state programs. Pros: trusted lab, accepted for real estate, results emailed. Cons: confirm whether the listing price includes the lab fee; turnaround depends on mail. Check price on Amazon

Best long-term kit

Radonova Radtrak (alpha-track) detector. Sits out 90 days to a year and gives a true seasonal average, which is the number that best reflects your actual exposure. Pros: most representative reading; low cost relative to its accuracy; minimal effort. Cons: you wait months for an answer; lab analysis required. Check price on Amazon

A long-term kit is the smart confirmation step after a borderline short-term result, or for anyone who wants one solid annual number without buying electronics.

Best digital monitors

Note one limitation: most consumer electronic monitors are not accepted as the official measurement in real estate transactions. For a home sale, use a certified mail-in kit or hire a measurement professional. Monitors shine for personal awareness and ongoing tracking.

Airthings Corentium Home (battery, no app required). The long-time best-seller. A standalone display shows 1-day, 7-day, and long-term averages. Pros: no app or Wi-Fi needed; runs on AA batteries; simple and reliable. Cons: no phone alerts or cloud history; slower to react to sharp changes than some rivals. Check price on Amazon

Ecosense RadonEye (RD200). A favorite among radon enthusiasts for its fast response and high sensitivity, with a companion app for charts and history. Pros: reacts quickly, good for watching ventilation or a fan kick in; app logging. Cons: needs mains power; app-dependent for full data. Check price on Amazon

Ecosense EcoQube (EQ100). A compact, lower-cost smart monitor with app tracking. Pros: budget-friendly entry into continuous monitoring; small footprint. Cons: fewer sensors than premium units; relies on the app. Check price on Amazon

Airthings Wave Plus / View Plus. Premium smart monitors that add CO2, VOCs, humidity, and (on View Plus) particulate sensors with cloud history. Pros: whole-home air-quality picture, remote access, dashboards. Cons: the extra sensors, not radon accuracy, drive the higher price; overkill if you only care about radon. Check price on Amazon

What the numbers mean

Radon is measured in picocuries per liter (pCi/L) in the U.S. and becquerels per cubic meter (Bq/m3) elsewhere. The EPA recommends fixing your home at 4 pCi/L or higher and says to consider acting between 2 and 4 pCi/L, because no level is risk-free. Health Canada uses a guideline of 200 Bq/m3 (about 5.4 pCi/L), and the World Health Organization suggests a reference level of 100 Bq/m3 (about 2.7 pCi/L) where feasible. Lower is always better. Testing tells you where you stand; mitigation is how you reduce your risk. For the science, see what radon is and whether it is dangerous.

If your confirmed result is at or above the action level, the next question is cost. Our guide to radon mitigation cost breaks down typical pricing for a sub-slab depressurization system.

FAQ

Do I really need to pay for a kit? Often no. Check your state radon program, local health department, or the American Lung Association first, since many offer free or low-cost kits, especially in fall and winter. Buy retail only if no program kit is available.

Are digital monitors accurate enough? Quality consumer monitors track radon well for personal awareness and long-term tracking, and they let you watch trends a one-time kit cannot. For a real estate transaction, though, use a certified mail-in kit or a licensed measurement professional, since electronic monitors are usually not accepted there.

What radon level should worry me? The EPA action level is 4 pCi/L; at or above that, retest to confirm and then plan mitigation. Between 2 and 4 pCi/L, consider acting, because there is no known safe level. Health Canada’s guideline is 200 Bq/m3.

How long should I run the test? A short-term charcoal kit runs 2 to 7 days under closed-house conditions. A long-term alpha-track kit runs 90 days or more for a seasonal average. A digital monitor runs continuously, but give it at least a week, ideally a month, before trusting the average.