Best Radon Detectors

5 Best Radon Detectors to Keep You Safe

Radon is one of the most dangerous elements that can pollute the air we breathe and the water we drink. Radon is a noble gas that’s hazardous for humans. It is colorless and odorless, which is why it cannot easily be detected.

Consider the following facts:

Furthermore, it is radioactive in nature and is formed when radioactive elements like Uranium decay in the soil. It can enter buildings through the pipelines, water supply, construction joints, foundation cracks, wall cavities, etc. Once it enters the building, it settles into the base or foundations and starts causing various health problems for the humans inhabiting the building. You can read more about radon here.

As mentioned earlier, radon is nearly impossible to detect without the use of specific instruments and tools called radon detectors which can let you know how high or low the level of radon in your home is. If the concentration of radon reaches or exceeds 4 picoCuries per liter (pCi/L), your building will be considered to be highly affected and you need to take measures for decontamination.

However, there are a lot of different types of these detectors. Some are simple passive radon tests, some are electronic, and some even have smart home functionality. That’s why I’ve written this article — to help you make an informed and educated choice about which radon detector to purchase.

What Are the Different Types of Radon Detectors?

Radon Detectors come in various different types. Some are simple one-off test kits whereas others are meant for continuous monitoring. Radon Detectors can be largely categorized into Passive Detectors and Active Detectors.

Passive Radon Detectors

Passive Radon Detectors are also known as Radon Test Kits and are generally used for one-time use. The radon detector sensor is packaged into the test kit and kept in a specific room to collect data. You have to allow it to collect data for a few days and then send the sample to a laboratory so you can find out the Radon Concentration percentage.

The following are the primary types of passive radon detectors.

  • Short-Term Radon Test Kit: These are used for fast answers. They generally use charcoal to absorb the radon and give you an indication about the radon concentration levels. You should leave them in the room for 2 to 4 days.
  • Long-Term Radon Test Kit: These are kits that use alpha track detection to accurately measure the radon concentration over a period of several months. When the alpha particles come in contact with the coated plastic in the detector, they create pockmarks. The number of pockmarks can be used as an indication of the radon levels. These are more expensive than short-term kits but are also more effective.
  • Water Radon Detectors: Radon can also enter water sources like showers, wells, etc. As such, they contaminate your drinking water and the vapors from the water can also further contaminate your home. You can use water radon test kits to detect the concentration level. If you detect radon contamination, you can use a water filter with granulated carbon to clear it for consumption.

Active Radon Detectors

Active Radon Detectors are devices that tell you the exact concentration of radon levels and don’t need to be sent to laboratories for interpretation. You simply have to place them in the suspected room and the device will automatically and instantly display the concentration level in the LED screen.

There are two specific types of active radon detectors on the market.

  • Electronic Radon Detectors: These are portable battery-operated devices that look like cell phones. Once the device detects the radon levels, it will display the readings in the inbuilt LED screen. Some of these devices also include sirens that go off when the radon level exceeds 4 pCi/L.
  • Smart Radon Detectors: These are similar to electronic radon detectors, but they can be connected to your smartphone via an app. As such, you can access your home’s radon information from anywhere in the world through your smartphone app.

Best Short-Term Radon Detector

1. First Alert RD1

First Alert is one of the most reliable and long-standing companies for home security devices such as carbon monoxide detectors, smoke alarms, etc. Their First Alert RD1 is an extremely simple, cheap, and safe radon test kit. It has been listed under the EPA Radon Gas Measurement Proficiency Program so it is officially recognized and reliable. Furthermore, this test kit also comes with a complementary laboratory testing so you can send the tested sample to the lab without incurring additional fees.

This First Alert RD1 kit comes with the radon sampler, an envelope with the First Alert laboratory’s address, and an instruction manual for use. The instruction manual is concise and all the steps are written clearly so you can follow it without trouble.

As a passive short-term radon detector, this kit can only be used once. However, it can detect radon presence quickly, generally within a couple of days. You have to place the radon sampler at the lowest point in your home, like the basement, for a minimum of 2 days. Following that, you can put the sample in the provided envelope and send it across to the First Alert laboratory for testing. And then you just have to wait for the results. Generally speaking, most people receive the results from the lab within 2 to 3 days.

This radon detector will give you a fair indication of whether you have a radon problem in your home. However, it is not as accurate as some of the more advanced testing methods. This should rather be used as a first step to determine if additional and more accurate tests are necessary. You should also keep the sampler away from wet or humid areas as the results can get easily tampered.

You should also note that this radon detector can cover only up to 2,000 square foot. Furthermore, it can only test the floor that it is exposed to. As such, if you want to test the radon on several floors, you’ll need multiple test kits. However, generally speaking, radon levels are highest at the lowest levels so testing only that one floor should be adequate.


  • Extremely cheap.
  • Can be done in 2-4 days.
  • No complex installations necessary.
  • Lab test is included with the cost of the radon detector.
  • Results are generated by experts and sent within a few days.


  • Can only work once.
  • Doesn’t produce the most accurate results. Is only the first step.
  • Humidity can spoil the sample.

Best Long-Term Radon Detector

2. Accustar Alpha Track

Accustar Alpha Track is a long-term radon detector that’s supposed to be installed for a period of 3 to 12 months for accurate results. If you’re in a time crunch, this is certainly not the right test for you. However, if you live in an area in which the levels of radon vary throughout the year, this can give you a better and more accurate overall picture of the average radon levels.

Like First Alert RD1, this too is a passive radon test kit. As such, you can only use it once and the sample you collect has to be sent to a professional laboratory for testing and interpretation. This detector is pretty easy to use. You simply remove the device from the pack and place it in the lowest level of your house for a period of 3 months to a year. There are two samplers in this kit and you have to send both of them to Accustar Labs in the provided pre-addressed postage-paid envelope along with the data sheet.

This device uses the Alpha Track system for radon detection. There is a piece of film inside each of the detectors and the radioactive radon gas starts decaying it over time. The number of decay marks on the film is then counted using a computerized system to detect the general level of radon. Accustar Labs is one of the country’s leading EPA-verified labs for radon detection and they use state-of-the-art electrochemical etching process to derive their results. They are completely reliable.

The lab generally sends the results within a few weeks so you have to be patient. You can check the progress, however, by referring to their website. Their report is exhaustive and easy to follow. While you can get a professional to interpret some of the complexities of the report, any layman can understand whether they have a radon problem.


  • Extremely simple to use.
  • There are two kits so you can compare the results provided from both.
  • The lab testing fee is included.
  • The lab’s results are easy to understand.
  • Is extremely accurate.


  • Can only be used once.
  • The process takes a long time.
  • It could take several weeks for the lab to process the sample and send its results.

Best Electronic Radon Detector

3. Radon Eye RD200 Plus

Radon Eye RD200 Plus is the best and most advanced electronic radon detector on the market. It is extremely easy to install. You just have to connect it to a 65mA or 12V DC power source. Following that, use bluetooth or WiFi to pair it with your smartphone so you can track the results via the app. The use of a smartphone app and WiFi makes it extremely advanced as you can essentially monitor the device from across the globe as well. However, the cost of WiFi connectivity is pretty steep as the wifi-enabled Radon Eye RD200 Plus is over twice as expensive as the non-wifi Radon Eye RD200.

This is an active radon detector so you can use the device to regularly test radon levels whenever necessary. You also don’t have to wait for several days or months for the results, you get the results within an hour. Furthermore, the radon levels are clearly displayed on the screen and you don’t have to rely on an external laboratory to interpret the results for you. All of those factors make Radon Eye RD200 Plus so much superior to the aforementioned radon test kits, though it is also considerably more expensive.

This radon detector is extremely accurate with a negligible error margin of 0.5pCi/l, which is a lot better than most radon detectors on the market. The results of this radon detector get updated every 10 minutes so you always have accurate data at hand. You should, however, note that this radon detector has an operational temperature of 10 to 40℃ so always keep it in a temperature-regulated atmosphere.

This radon detector also retains all of the recorded data for a complete year. As such, you can download the results for any given period within a year for comparisons and long-term analysis. However, the process of calculating the overall average has to be undertaken by the user. The app or the display don’t come with features to calculate an average over an extended period. They only display the current levels of radon.


  • Easy to use.
  • Extremely accurate results.
  • Is a long-term solution.
  • Can update radon level readings every 10 minutes.
  • Can be connected to a smartphone.
  • Radon levels over an entire year can be exported to your computer.
  • Has wifi connectivity for long distance monitoring.


  • Only displays the current radon level. Can’t display an average.

Best Smart Radon Detector

4. Airthings Wave

Airthings Wave is an extremely accurate and easy-to-use smart radon detector. This is battery-operated radon detector so it’s completely portable and you don’t need to worry about finding a power source. It uses 2 AA batteries with a lifespan of about 1.5 years so the battery life is pretty great.

The best aspect of the Airthings Wave radon detector is its smartphone app. You can download the Airthings app to your smartphone app and then pair your device to your phone through bluetooth. Several users have noted that the bluetooth app is a little primitive and WiFi connectivity would have been more suitable. However, that shouldn’t pose much of an issue. Furthermore, it is less than half the cost of the aforementioned WiFi-enabled radon detector, which makes it pretty worthwhile.

This radon detector is fairly accurate and has an easy-to-follow color-coded means of indicating rising radon levels. Green indicates safe levels. Yellow is a warning if the radon level is rising close to the critical level. Red indicates that the radon levels have exceeded 4 pCi/L, which is pretty hazardous.

In addition to radon detection, this device also works as a temperature and humidity detector. You can get all the relevant information in your smartphone app. Including humidity detection with this device is pretty smart thinking because you are supposed to install radon detectors in areas with low humidity. As such, if you find that the humidity in the area is high, you can move the radon detector.

All of the data and readings are stored in the device, not the app. As such, you can export the data to your app or any other device whenever necessary. The best aspect of the app was that it also displayed a graph of the radon levels over the past day, week, or months. This made comparing the levels easy and the app also displayed the average over an extended period.


  • Easy to use.
  • Battery operated.
  • Relatively reasonable by active radon detector standards.
  • Can also record temperature and humidity.
  • The app is exhaustive and also displays graphs of the past days, weeks, and months.
  • Can display average radon levels.
  • Color-Coded indicators are easy to follow.


  • Doesn’t have wifi connectivity. As such, you have to be near the device to monitor it.
  • Not as accurate as Radon Eye RD200.

Best Water Radon Detector

5. Accustar WTR 100

Accustar WTR 100 is an easy home-use radon water test kit. The package comes with a single vial, an instruction manual, and a self-addressed envelope. The process is pretty simple, you just have to put the sample water into the vial while following the provided instructions very carefully. Following that, place the vial in the envelope and send it out to the Accustar laboratory. You will receive the results in a couple of days or weeks.

The only thing you have to be concerned about is following the instructions to the letter. There can be no air bubbles in the water, just water. As such, you have to follow the instructions to make sure you meet all of their requirements. Furthermore, the sample cannot be stored in freezing temperatures like a refrigerator. As such, you shouldn’t take the test during cold winters. Failure to follow any of their instructions will result in the test being voided.

However, if you follow all the instructions carefully, you will soon receive your results and you’ll find out whether your water had radon contamination. You can use this method to test the water from your shower, sink, well, or any other source of water.

This is not technically a radon detector. However, when it comes to water testing, there are no home-use easy radon detectors on the market. You simply have to get the test kit and send out the sample to the appropriate laboratory.


  • Reliable laboratory.


  • Following all the instructions can be a little hard.
  • Lots of people have complained about their test having been voided.

Which Factors to Consider when Buying Radon Detectors?

When purchasing radon detectors, you need to take the following factors into consideration.


As mentioned above, there are several different types of radon detectors on the market. You have passive radon test kits that are cheap and simple to use but can only be used once. Furthermore, you need to send results to laboratories for interpretation.

If you want to detect the radon levels immediately and without involving external laboratories, you can use active radon detectors. These can be used whenever you want and they give accurate immediate readings.

Testing Period

Short-term radon detectors may take up to 3 months for readings. Long-term radon detectors may take up to a year for accurate readings. And electronic radon detectors can give you immediate readings.

Finally, the choice is yours. You need to determine how urgent your needs are. For example, if you don’t want to invest in an expensive electronic radon detector but need a relatively fast reading because you’re selling your home, you can use a short-term radon test kit.


This only applies to active radon detectors. They are either battery-operated or they need to be connected to a power outlet. You need to determine which one is more suitable for your needs and how much portability you require.


Go through all of the device’s reviews to make sure you get an accurate radon detector. Compromising the accuracy means you’re compromising on your and your family’s safety.

Ease of Installation

Most modern radon detectors are fairly easy to use. You just have to follow the instructions in the provided manual. However, not too long ago, all electronic radon detectors had to be operated by professionals. You should try not getting one of those complex “professional” devices.

If you are confused about how to operate the radon detector, you should hire a professional to help you out.

Other Important Factors

Besides the aforementioned points, you should also take the following factors into consideration:

  • The electronic radon detector should update its readings within frequent intervals.
  • The radon detector should be bought from or certified by a qualified laboratory.
  • If you get a passive radon test kit, be sure that the cost of shipping and laboratory testing is all-inclusive. Otherwise, you will have to find a qualified laboratory on your own and pay an additional amount for shipment and testing.

Frequently Asked Questions

The following are answers to some of the most commonly asked questions about radon contamination and radon detectors.

Where Does Radon Originate?

Radon originates from the natural decay of radioactive minerals like uranium in earth’s soil. As Uranium decays, radon alpha particles are released and they can seep into the buildings through various entry points.

There are generally five common entry points for radon gas:

  • Natural stones like granite and limestone that can decompose over time and exude radon.
  • Cracks in the foundation through which radon can enter from the soil underneath.
  • If your house uses a well system, then the radon from the surrounding soil can seep into the groundwater.
  • Cracks, holes, and crevices in walls and concrete can pave the way for radon gas.
  • Rock formations under the house can generate radon and, over time, enter through the basement.

What Kind of Buildings Are at High Risk of Radon Contamination?

All kinds of buildings are susceptible to radon contamination. There’s a common misconception that radon contamination can occur more easily in old houses with basements. In truth, radon contamination can also occur without the presence of a basement and even in recently constructed homes.

How Much Radon Level is Safe?

Even slight exposure to radon can be hazardous to your health. There is no “safe” level, but WHO recommends that around 2.7 pCi/L is acceptable. According to the EPA, your risk of contracting lung cancer significantly increases if the radon concentration reaches or exceeds 4 pCi/L.

What are the Signs of Radon Contamination?

Signs of radon contamination are similar to those of lung cancer. They may include wheezing, hoarseness, chest aches, headaches, cold, bloody coughing spells, etc.

What’s the Best Location for the Radon Detector?

The radon detector should ideally be placed in the lowest point of your home, i.e., your basement. Radon tends to dissipate as it reaches higher, so you won’t get an accurate reading from higher rooms. If there are any points in your house that can constitute a point of entry, you can install your detector near them.

How to Get Accurate Results from the Radon Detector?

Follow these tips in order to maximize the accuracy of your radon detector tests:

  • Keep all doors and windows closed, except for the normal points of entry and exit. This allows the device to measure trapped radon.
  • Don’t test while there’s a strong wind or rainfall. Wait for calm weather.
  • Leave the test for longer periods for greater accuracy.
  • Place the test in the lowest living space such as a basement.
  • Don’t expose the radon detector to moisture or humidity.
  • Keep the radon detector about 2 feet from the ground and 3 feet from windows.

What’s the Lifespan of a Radon Detector?

Electronic radon detectors can last up to 10 years. Their lifespan is similar to those of carbon monoxide detectors or smoke detectors.

How to Install a Radon Detector?

You should install the radon detector at the lowest point in your home, which is usually the basement. Once you have selected the ideal location, you need to follow the radon detector’s manual for instructions.

You should also follow these tips for accurate installation:

  • If you’re using a short-term radon test kit, be sure to keep the doors and windows closed for at least 2 days to prevent any fluctuations and interference.
  • Radon generally enters from the soil underneath the house’s foundation. As such, most of the contamination is found in the lower levels. As such, you should target the basement first.
  • Don’t install the radon detector in a bathroom, kitchen, or laundry room as humidity and moisture can interfere with the reading or cause the device to malfunction.
  • Don’t install the radon detector in tight spaces like sump pumps, crawl spaces, or construction joints as they may lead to a false positive or an unusually high reading.
  • If you suspect any crack, venting pipe, etc, of being a point of entry for the gas, that’s where you should install the radon detector.
  • Get rid of objects and devices that exude toxins or fumes that can tamper with the reading.
  • Take note of the start and end dates of the test along with the reported results. This will help with comparisons.
  • If the result is higher than 4 pCi/L of contamination, you need to take another test just to make sure. If you still get high results, contact an expert for radon mitigation.

What to Do After I Detect High Levels of Radon?

If you detect a hazardous level of radon contamination in your home, you should immediately contact a professional contractor certified at radon mitigation. You can contact your state’s radon officer for recommendations.

The contractor will proceed by first sealing all cracks and crevices in the house’s foundation to block out any potential points of entry. Following that, they will install a mitigation ventilation system to facilitate air flow and get rid of existing radon.