According to the Environmental Protection Agency (EPA), radon gas is the second leading cause of lung cancer in the United States behind smoking and is responsible for around 21,000 lung cancer-related deaths each year. The EPA estimates that one out of 15 homes in the U.S. has unhealthy levels of radon.

So what is radon? Radon is a radioactive gas that can be harmful to humans and animals when they’re exposed to high levels of it. Radon gas exposure is caused by a breakdown of uranium within the earth; the radon gas rises and enters through cracks and other holes in a building’s foundation.

What makes this gas so deadly is that it is undetectable by humans—it’s odorless and invisible. It doesn’t cause immediate health problems, but extended exposure to it does. That’s why you need specialized equipment to detect radon in your home or business.

How to Detect Radon Gas

There are a few different methods that you can use to detect radon within your home or business. The two main radon detection methods are active and passive tests.

The most common passive test uses a radon test kit that is sent to experts for analysis. Using radon test kits, property owners can measure radon levels for two to 90 days for short-term passive tests, or they can measure 90 days or more for long-term passive tests.

The radon kit is then sent to a laboratory, and the lab sends the property owner an analysis of the sample. These tests require no special training to conduct, so property owners can perform these tests themselves.

The other common radon detection method available for property owners is the active detection method. Active radon monitoring devices require a power source and can provide almost instantaneous results at any given time. These devices can provide both short-term and long-term results, but they’re usually more costly than passive radon detection kits.

Why You Need a Radon Detector

Exposure to radon for prolonged periods of time or in high concentrations can be deadly and lead to long-term health problems, such as lung cancer.

Using a radon gas detector or radon detection kit, you can identify radon gas levels within your home or business and prevent any unnecessary exposure to this harmful gas. If your building does test positive for radon, you can then act accordingly to prevent further exposure.

One method for eliminating radon gas exposure is sealing off any cracks or gaps in the building’s foundation. Sealing and venting areas of exposure can also help reduce radon levels. Preventing further exposure is straightforward once you know you have high levels of radon.

The 3 Best Radon Detectors on the Market

It’s important to know your building’s radon level so you can keep your family or employees healthy and safe from its dangerous long-term health effects. These active radon tests will help you do just that and provide you with both short-term and long-term results and monitoring. Here are the best radon detectors on the market today.

Radon Eye RD200

Using the latest in smart technology, the Radon Eye RD200 boasts 20 times the sensitivity compared to other radon detectors. That’s because its dual-structured pulsed ionization mechanism enables it to provide more accurate detection.


The Radon Eye RD200 provides its first reliable results within the first hour of operation, meaning you no longer need to wait extended periods of time for accurate results.

A useful feature of the Radon Eye RD200 is its ability to log and share data to your smartphone or PC, allowing you to conveniently observe and monitor radon levels within your home or business. This data can be easily exported to Excel so you can view and manipulate the data easily in a spreadsheet.

The Radon Eye RD200 displays data in a graph format to ensure you can easily understand the results and readings provided. Additionally, the device supports Bluetooth connectivity via an app so you can easily access the device using a smartphone or tablet.

What we like

  • Quickly provides accurate and reliable readings, allowing you to get immediate results
  • Data can be easily accessed through Bluetooth connectivity and an accompanying app
  • Much more sensitive than competing devices
  • Data can be exported directly to your PC or smart device in a graph or spreadsheet format

What we don’t like

  • At over $200, the device is a little pricey

Radex MR107

The Radex MR107 is an active radon detection device that is highly sensitive and provides accurate and reliable results. This device is suitable for both home and workplace environments, and it is user-friendly.


In addition to its primary radon detection functionality, the Radex MR107 also provides additional features, such as relative humidity and temperature measurement, to provide you with more comprehensive results. This device comes with Windows software that you can download and use for free.

Using this software, you can easily transfer data gathered by the Radex MR107 to your PC and analyze and monitor the results within your home or business. Another useful feature is an adjustable alarm that is triggered when the device detects unsafe levels of radon.

The Radex MR107 also measures the surrounding radon levels relative to the surrounding temperature and humidity, ensuring more accurate and relative results. This provides you with a more complete picture and additional context so you can track dynamic changes in surrounding radon levels more reliably than with most other devices.

What we like

  • The ability to transfer results to the free Windows software is useful and helpful
  • Additional features such as humidity and temperature readings provide more context when compared with relative radon levels
  • User-friendly design makes the device easy to use for both home and business owners
  • It retails for under $200

What we don’t like

  • Lack of a built-in interface makes results more difficult to identify
  • Can only be charged via USB, and the battery lasts for up to six days

Corentium Home by Airthings

The Corentium Home is a portable lightweight radon detection device that provides accurate results within 24 hours. You can view results easily with its built-in LCD screen without the need of any external devices. This allows you to conveniently monitor radon levels in your surrounding environment.


This device is resistant to a variety of environmental and physical conditions, such as electromagnetic interference, dust, and weather. This helps ensure that its readings are accurate and reliable.

Boasting a two-year battery life, the Corentium Home can provide long-term results and monitor your surrounding radon levels with great precision. You can easily replace the three standard AAA batteries, allowing your device to last up to 10 years.

What we like

  • Its portability allows you to conveniently monitor radon levels in various locations
  • High resistance to electromagnetic and environmental conditions ensures more reliable results
  • Built-in LCD screen allows you to view and monitor results immediately without the need for any external devices
  • Two-year battery life and replaceable AAA batteries allows for long-term use
  • Its price—under $150—means you get great value for good functionality

What we don’t like

  • Unable to export and transfer data to a PC or other devices

Where to Place Your Radon Detector

Once you’ve selected the radon detector that will work best for you, make sure you follow instructions and place it properly in the building you’re testing.

Because radon gas rises up from the ground, place the radon detection device or test kit in a room that is closest to the ground for the most accurate and reliable results. For example, if you have a basement, you should place the detection unit there.

For the best and most accurate results, you should keep all windows and doors closed during the testing period prescribed by your device or test kit. In long-term tests, however, closed house tests conditions are not necessary.