Mail-In Kit or Always-On Monitor? Best Radon Detector Options for the Lowest Lived-In Floor

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You can’t see, smell or taste radon, and the EPA says testing is the only way to know your level of exposure. The best radon detector for you depends on the question you’re asking. A mail-in lab kit gives you one inexpensive snapshot. A digital monitor keeps counting for months or years, so you can watch levels rise and fall with the seasons and check whether a mitigation system is working.

We compared six options sold by Amazon.com or the brand’s own store: two short-term lab kits and four battery-powered digital monitors, from a plain-display unit to a Wi-Fi air quality monitor. For each, we say what the listing states about lab fees, results and readings, and we flag what it leaves out.

One caution before you buy: a home radon detector tells you a number, not what to do about it. If a test comes back at or above EPA’s 4 pCi/L action level, follow up and talk to a qualified radon professional.

Our Top Radon Detector Picks at a Glance

Price key: $ under $50 · $$ $50–$100 · $$$ $100–$175 · $$$$ $175+. Prices change often; check Amazon for today’s price.

1. First Alert Radon Gas Test Kit (RD1): Best Short-Term Test Kit

First Alert’s RD1 is the classic hardware-store radon test: a small kit you set out in your home, seal up when the exposure period is over, and mail to a lab for analysis. There’s no screen and no app. You get one result for one stretch of time, which is exactly what EPA describes as a short-term test.

The listing keeps its claims short. First Alert says the kit is “Listed under the EPA radon gas measurement proficiency program” and that it “Includes test materials and lab fees, excluding NJ state fees.” Results are “emailed within 72 hours of lab receipt,” so the clock starts when the lab gets your package, not when you drop it in the mail. The kit is “Recommended for use only within the United States.” The listing doesn’t state how many days the kit should stay out or whether return postage is prepaid, so read the package instructions before you start.

Day to day, the work is mostly setup. EPA’s guidance for short-term tests is to keep windows and outside doors closed as much as possible, place the kit in the lowest lived-in level of the home, and keep it at least 20 inches above the floor, away from drafts, high heat, high humidity and exterior walls. When the test ends, reseal it and send it off right away.

It suits first-time buyers, new homeowners and anyone who wants a baseline number before deciding whether a digital monitor or a follow-up test is worth it.

Why we like it

• Lab fee included outside NJ
• Emailed results
• Very low cost

Watch out for

The listing doesn’t give the exposure period or say whether return postage is covered, and one kit gives one result, so plan on a follow-up test if the number is high.

Check Price on Amazon →

2. empowerDX Radon Test Kit: Best Lab Kit With Stated NRPP Certification

The empowerDX Radon Test Kit is another short-term mail-in test, sold on Amazon by DNA Diagnostics; empowerDX’s own site identifies DNA Diagnostics Center, Inc. as doing business as empowerDX. You collect the sample at home, register it, and send it back to the company’s lab for analysis.

The listing leans on the lab. It says samples are “Tested by the #1 radon testing laboratory in the country,” which is the brand’s own claim, and that the lab is “certified by the National Radon Proficiency Program (NRPP), and listed by the Environmental Protection Agency.” The title abbreviates that as “NPPR,” which looks like a typo for NRPP. Results are promised within three to five business days after the lab receives your sample.

The process is described as three steps: order the kit, collect the sample, and return it “using any carrier of your choice.” That suggests return shipping is on you, so budget for it. On fees, the listing says only that New Jersey residents pay a $10 state-mandated lab fee at registration; it doesn’t spell out that lab analysis is included for everyone else, so confirm that on the package or with the seller. Like the First Alert kit, it only accepts samples from customers who live in the USA.

It suits buyers who want a simple lab test and like knowing the lab’s stated proficiency credential, especially as a second short-term test to confirm a high first result.

Why we like it

• Named NRPP-certified lab
• Results in 3–5 business days
• Any return carrier

Watch out for

Return shipping appears to be your cost, and the listing only mentions lab fees for New Jersey, so confirm what the price covers.

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3. Airthings Corentium Home 2 (325): Best Overall Digital Radon Monitor

Airthings calls the Corentium Home 2 “The original radon detector, updated.” It’s a small, battery-powered digital monitor that sits on a shelf in the room you want to watch and counts radon continuously, showing results on its own display. Compared with a mail-in kit, there’s nothing to send away and no lab fee, and it keeps going after the first result.

The redesigned screen shows short-term and long-term radon averages alongside current environmental readings, with simple GOOD, FAIR or POOR indicators. This version adds Bluetooth and “bonus temp and humidity sensors,” and Airthings says the app’s graphs show how radon rises and falls so you can act on it and keep monitoring to make sure levels stay low. The brand also offers what it calls personalized tips.

Because it runs on batteries, you can move it between rooms or put it in the basement with no outlet nearby. Airthings says it uses the brand’s patented radon sensing technology, “used and recommended by thousands of radon professionals and home inspectors,” which is a brand claim. Pairing it with an Airthings Hub or View series monitor unlocks 24/7 remote monitoring and notifications; on its own, it’s a Bluetooth device you check up close.

It suits homeowners who tested once, want to see how radon behaves across seasons, and prefer reading a screen to opening an app.

Why we like it

• Short- and long-term averages on screen
• No lab fees
• Moves anywhere on batteries

Watch out for

You’ll need an Airthings Hub or View monitor for remote alerts, and the listing’s warranty and weight fields are empty.

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4. Airthings Wave Radon (2950): Best Battery-Powered Smart Radon Detector

Airthings’ Wave Radon is a round, battery-powered radon detector designed to mount on a wall or sit on a shelf. Instead of a numeric screen, it uses a light: wave your hand in front of it and you get a green, yellow or red indicator of the air quality. The detailed numbers live in the Airthings app on your phone.

The listing makes the case for continuous monitoring. Airthings says radon “fluctuates daily and is highly dependent on many factors such as weather conditions” and calls long-term monitoring “crucial.” The Wave Radon reports both long-term and short-term radon results to your smartphone over Bluetooth and can generate a radon report through the Airthings Dashboard. It also measures humidity and temperature.

Day to day, you glance at the light or open the app when you’re nearby. This second-generation Wave has what Airthings calls Smartlink, which means it can connect to an Airthings Hub to put your data online around the clock; without a Hub, data syncs when your phone is in Bluetooth range. Airthings’ warranty note says a five-year extended warranty is available if you register on its website within 30 days of purchase.

It suits households that like smart-home gadgets and want trend charts, but don’t need a number on the device itself.

Why we like it

• Wave-to-check color light
• App reports and dashboard
• 5-year warranty with registration

Watch out for

Without a screen, you depend on the app for numbers, and 24/7 online access needs a separate Airthings Hub.

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5. Aranet Radon Plus: Best for Fast, Frequent Readings

The Aranet Radon Plus is a portable digital radon monitor from Aranet, sold on Amazon by the brand’s US store. Its headline feature is speed: the listing describes continuous radon measurement every 10 minutes, and calls it “the only truly portable radon monitor on the market” to do so. That last part is Aranet’s claim.

It runs on two AA batteries, and Aranet says its ultra-low-power design gives up to seven years of battery life. Along with radon, it measures temperature, relative humidity and atmospheric pressure. The E-Ink display gives a color-coded green, yellow or red indication, and you can switch it to show real-time, 24-hour, 7-day or 30-day averages. It shows radon in pCi/L, the unit US guidance uses, or Bq/m³.

You can use it on its own or connect it to the Aranet app for detailed results. In practice, frequent updates help when you want to see cause and effect, such as how radon changes overnight with the house closed up, or whether levels dropped after a mitigation fan went in. The listing doesn’t mention a year-long average, so for a true long-term picture you’d track results in the app over time.

It suits hands-on homeowners and anyone fine-tuning a basement after mitigation who wants frequent numbers and long battery life.

Why we like it

• 10-minute radon updates
• Seven-year battery claim
• pCi/L or Bq/m³

Watch out for

The display tops out at a 30-day average and the warranty field is empty, so check Aranet’s warranty terms before buying.

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6. Airthings View Plus (2960): Best Radon and Whole-Air Monitor

Airthings’ View Plus is a battery-powered indoor air quality monitor that includes a radon sensor. Alongside radon, it measures PM2.5 particles, carbon dioxide (CO2), VOCs from things like cooking fumes and cleaning products, humidity, temperature and air pressure. A customizable eInk screen shows the readings you choose.

It connects over Wi-Fi, so you can check live data from anywhere and get notifications when something changes. That convenience comes with conditions spelled out in the listing: the monitor “requires the Airthings app to function,” an account is required (Airthings says it asks only for your email and name), and the monitor and app both need internet access, with data saved in the cloud. The operating range is listed as 39 to 104°F, which is worth noting for an unheated basement in winter.

Setup is described as quick, and because it’s battery-powered you can place it without running a cable. Airthings says it has 15 years of experience in radon and air quality monitoring and more than 1,000,000 users; those are brand figures. Registering for the free extended warranty raises coverage to five years.

It suits households that want radon and everyday air quality in one device and like the idea of alerts while they’re away. Note that it is not a carbon monoxide alarm.

Why we like it

• Seven sensors in one
• Remote notifications over Wi-Fi
• Five-year warranty option

Watch out for

It won’t work without the app, an account and internet, and it doesn’t detect carbon monoxide, so keep CO alarms installed.

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How We Chose the Best Radon Detectors

We kept only listings that were in stock and sold by Amazon.com or the brand’s own store, then compared what each one actually states:

• Test type: short-term mail-in lab kit or continuous digital monitor.
• Lab fees and turnaround: whether the listing says the lab fee is included and how fast results arrive.
• Readings: short- and long-term averages, update speed and units (pCi/L).
• Connectivity and power: screen, Bluetooth or Wi-Fi, and battery claims.
• Seller, warranty field and sales rank, with empty fields flagged.

Radon Detector Buying Guide

Best Radon Test Kit: Short-Term vs. Long-Term

EPA’s A Citizen’s Guide to Radon describes two general ways to test. Short-term tests stay in the home for two to 90 days, depending on the device, and are the quickest option. Long-term tests stay for more than 90 days and are more likely to reflect your year-round average, because radon varies from day to day and season to season. The First Alert and empowerDX kits are short-term lab tests. EPA lists continuous monitors among the devices used for short-term testing, but a monitor you leave running also builds a longer record over time.

Lab Fees, Mailing and Timing

With a mail-in kit, the price on the box isn’t always the whole cost. First Alert says its kit includes lab fees, excluding New Jersey state fees, and emails results within 72 hours of lab receipt. empowerDX mentions only a $10 fee for New Jersey residents and says you can return the sample by any carrier, which implies you pay the postage. EPA’s guide says to reseal the kit and send it to the lab right away once the test ends, so mail it promptly.

Best Home Radon Detector Placement and Closed-House Conditions

EPA’s guide says to place a test in the lowest lived-in level of the home (the basement if it’s used often, otherwise the first floor), in a regularly used room but not the kitchen or bathroom, at least 20 inches above the floor and away from drafts, high heat, high humidity and exterior walls. For short-term tests, keep windows and outside doors closed as much as possible, and for a two- or three-day test, close them at least 12 hours before you start. Avoid short tests during unusually severe storms or high winds.

Best Digital Radon Monitor Features

All four monitors here are battery-powered. The Corentium Home 2 shows short- and long-term averages on its own screen. The Wave Radon relies on an app and a wave-to-check color light. The Aranet Radon Plus updates every 10 minutes and lists the longest battery claim (up to seven years). The View Plus adds Wi-Fi and five more air quality sensors but requires the app, an account and internet access. Several also report humidity; if your basement runs damp, a dehumidifier addresses moisture, which is a separate problem from radon.

Best Radon Tester for Follow-Up Testing

EPA recommends a follow-up test if your first short-term result is 4 pCi/L or higher: a long-term test for a better picture of your year-round average, or a second short-term test if you need results quickly. If the first short-term result is more than twice the 4 pCi/L action level, EPA says to take a second short-term test immediately. A second mail-in kit, or a monitor left running, can serve that role. EPA also suggests retesting after mitigation, after major renovations, and every two years to make sure levels stay low.

What the EPA Action Level Means

On its action level page, EPA recommends fixing homes with radon at 4 pCi/L (picocuries per liter) or more and, because there is no known safe level of exposure, recommends that Americans consider fixing their home for levels between 2 and 4 pCi/L. The page puts the average indoor level for American homes at about 1.3 pCi/L. EPA’s guide adds that lowering high radon levels requires technical knowledge and special skills and recommends using a contractor trained to fix radon problems. EPA’s test kit and professional finder points you to your state radon program and to the two national proficiency programs (NRPP and NRSB) for credentialed testers and mitigators.

Radon, Air Safety and Your Ohio Home

A radon detector isn’t a carbon monoxide alarm, and none of the monitors here measure CO. Keep working CO alarms near sleeping areas; our guide to the best carbon monoxide detector covers plug-in, digital and sealed-battery models. If you’re buying a home, EPA’s guide notes that buyers often ask whether a house has been tested and whether elevated levels were reduced, and that buyers frequently want tests done by someone not involved in the sale.

Whether a policy has anything to say about radon testing or mitigation depends on the policy, so ask your agent rather than assuming. New owners can start with our insurance tips for first-time Ohio homeowners and the Ohio homeowners insurance guide.

Frequently Asked Questions

What is the best radon test kit for a first test?

A short-term mail-in kit is the cheapest place to start. The First Alert RD1 listing says it includes test materials and lab fees (excluding New Jersey state fees) and emails results within 72 hours of lab receipt. empowerDX names an NRPP-certified lab and promises results in three to five business days.

Are digital radon monitors accurate enough to replace a lab test?

They answer a different question. EPA lists continuous monitors among short-term test devices, and a monitor shows how levels change over time. For a home sale, EPA’s guide says buyers often want testing by someone not involved in the sale, so a professional test may still be expected.

What radon level is too high?

EPA recommends fixing your home at 4 pCi/L or more and recommends considering a fix between 2 and 4 pCi/L, since there is no known safe level. If a first short-term test reads 4 pCi/L or higher, EPA recommends a follow-up test before deciding.

Where should I put a home radon detector?

EPA says the lowest lived-in level of the home, in a regularly used room that isn’t the kitchen or bathroom, at least 20 inches above the floor and away from drafts, high heat, high humidity and exterior walls.

Does a radon detector also detect carbon monoxide?

No. None of the radon detectors here measure carbon monoxide. The Airthings View Plus tracks CO2, VOCs and PM2.5 as well as radon, but CO2 is not carbon monoxide. Keep separate CO alarms installed.

The Bottom Line

For a first answer, the First Alert RD1 is the simplest start, with lab fees included outside New Jersey, and the empowerDX kit names an NRPP-certified lab. To keep watching, the Airthings Corentium Home 2 is the best radon detector for most homes, with short- and long-term averages on screen. The Wave Radon suits app users, the Aranet Radon Plus updates every 10 minutes, and the View Plus adds Wi-Fi and whole-air sensors. Whatever you choose, test the lowest lived-in level, follow up on high results, and call a qualified radon contractor for anything at or above 4 pCi/L.

Buying a home or fixing a basement and want to know how your coverage works? Call Jeff Smith’s State Farm office at (740) 354-7747 or get a free coverage review.