Updated April 2022
Header Image
Why trust BestReviews?
BestReviews spends thousands of hours researching, analyzing, and testing products to recommend the best picks for most consumers. We only make money if you purchase a product through our links, and all opinions about the products are our own. Read more  
BestReviews spends thousands of hours researching, analyzing, and testing products to recommend the best picks for most consumers. We only make money if you purchase a product through our links, and all opinions about the products are our own. Read more  
BestReviews spends thousands of hours researching, analyzing, and testing products to recommend the best picks for most consumers. We buy all products with our own funds, and we never accept free products from manufacturers.Read more 
Bottom Line
Pros
Cons
HOW WE TESTED

We recommend these products based on an intensive research process that's designed to cut through the noise and find the top products in this space. Guided by experts, we spend hours looking into the factors that matter, to bring you these selections.

35
Models
Considered
170
Consumers
Consulted
8
Hours
Researched
Category cover

Buying guide for best radon detectors

Long-term exposure to radon gas can create health problems that dramatically affect the quality and length of your life. Radon occurs naturally but is typically only found in very low levels. However, the gas can accumulate in your home and climb to dangerous levels. Since humans cannot sense radon, the only way to know for certain if your home is safe is to get a radon detector.

A radon detector either continually monitors your home’s air for radon or collects radon data for later analysis. It can be a short-term detector or a long-term detector. No matter which type of radon detector you buy, it must be accurate and easy to install and use so there is less of a margin for human error.

Before purchasing a radon detector, it’s wise to learn what radon is, where it comes from, and how it affects the human body. After that, you can examine how a radon detector works so you know which features are the most important.

radon detector
You cannot see, smell, feel, or taste radon. This is why you need a detector to determine the level of radon in your home.

How to buy the best radon detector

Understanding what radon is

Radon gas occurs naturally when uranium, thorium, or radium break down. Since these three items are common elements in the earth’s crust, people are constantly exposed to some level of radon.

According to the EPA, the average level of radon in outdoor air is 0.4 picocuries per liter of air — a picocurie is one trillionth of a curie. The average level of indoor radon is 1.3 pCi/L. Because there is no known safe level of radon, the EPA recommends homeowners take action to lower indoor radon levels if they exceed 2 pCi/L.

How radon gets into the home

Radon is a noble gas — it is stable and does not react with other elements — that is 7.5 times heavier than air. These two traits make it susceptible to air pressure and currents. This means radon gas can easily navigate up through the soil and enter the home through the tiniest cracks or gaps in a building’s foundation.

Radon gas is water-soluble. This means it can be absorbed by groundwater. When well water is used for tasks such as washing the dishes, showering, and cooking, radon gas can escape into the air of the home. Admittedly, this only accounts for up to 2% of the total radon found inside the home.

Because radon gas is easily influenced by air currents, turning on a forced air heating or cooling system while keeping the doors and windows closed disperses radon throughout the entire home.

Why is radon bad?

When uranium, thorium, or radium decay, three forms of radiation are released: alpha particles, beta particles, and gamma rays.

Alpha particles cannot penetrate the skin. However, they can penetrate the cells that line the lungs. If you breathe in radon, most of it will be exhaled. However, some particles may remain in the lungs. These are the particles that decay inside the body and cause irreparable damage.

Radon found in drinking water can be ingested. While this can cause damage to the stomach and other internal organs, scientists currently believe, in most cases, ingesting radon is not a major cause of concern.

How a radon detector works

There are two types of radon detectors you can purchase for your home: passive and active.

Passive radon detector: A passive radon detector monitors radon and its daughter particles — particles that remain after the original radioactive particles have decayed — through one of three methods: a charcoal scintillation device absorbs radon (and its products), an alpha track detector counts alpha particles that strike a plastic film, or an electret ion device measures the amount of radon present via a reduction of electrical charge in statically charge Teflon disc. These types of devices require no electricity and must be sent out to a lab for analysis.

Active radon detector: An active radon detector requires electrical power and continuously monitors and records the level of radon or its daughter products. Many offer hourly readings as well as an average result for the entire test period. These models are typically more expensive than passive radon detectors, but there are no lab fees involved. Additionally, they may have a much faster turnaround, often providing the first measurement within 24 hours.

Home radon levels can elevate during rainstorms and winter months.

STAFF
BestReviews

What features do radon detectors have?

Accuracy

Accuracy is a primary concern. A radon detector that does not accurately measure radon levels in your home cannot protect you. Since there are many factors that affect radon levels, causing spikes in either direction, the duration of the monitoring is also an important factor to consider in a device's overall accuracy.

Short-term vs. long-term

A short-term radon test is typically considered anything under 90 days. Because radon can fluctuate depending on a wide variety of factors, including the season, it is best to get a long-term device.

Ease of installation and operation

Most radon detectors are easy to install and operate: just mount it and leave it be.

Hourly readings

While long-term readings are the best and most accurate, it can be useful to know what the radon level is from hour to hour. If you have a model that continuously monitors levels, you can make adjustments in real-time to see how effective those strategies are at lowering radon levels.

Measure other elements

High-end radon detectors often monitor a variety of indoor pollutants, such as pollen, VOCs, and mold. These models may also track temperature and humidity. If this sounds desirable, and you have the budget, consider a high-end radon detector with these features.

Accompanying app

If you want to monitor your radon detector remotely and examine the data it collects in different ways, a model that comes with an app is your best option. These smart radon detectors may also send you an alert when the air quality in your home becomes unhealthy.

radon detector
DID YOU KNOW?
Although radon was discovered in 1900 by a German chemist named Friedrich Ernst Dorn, it took until the late 1980s for it to be recognized as a health hazard.
STAFF
BestReviews

How much do radon detectors cost?

Inexpensive

For less than $30, you can purchase a single-location, short-term, passive radon test. These are not considered the most accurate, but they can be suitable when time is the primary factor.

Mid-range

From roughly $60 to $125, you will find low-end active detection models. These independent items can be moved from room to room if needed. Many offer initial data in as little as 24 hours but assess long-term data averages as well.

Expensive

Once you move above the $150 price mark, the devices become more sophisticated. At the high end, you can monitor a wide variety of airborne particles, such as radon, dust, allergens, VOCs, and mold. These models are typically smart devices that connect to your phone and offer a much broader scope of functionality.

Radon levels constantly fluctuate. To get an accurate understanding of your home’s radon levels, it is recommended that you perform a test that lasts at least 90 days.

STAFF
BestReviews

Tips

  • Test your home. If you have never tested your home for radon, it is important to do so because radon is undetectable otherwise.
  • Avoid areas of high concentration. If you have an area with high radon levels in your home, such as the basement, avoid this area until you can come up with a solution to lower levels.
  • Increase airflow throughout your home. To help reduce radon gas, open windows and use fans to circulate fresh air.
  • Seal cracks. If you find cracks or gaps in flooring or walls, use the appropriate material to seal these openings.
  • Get help. If you have high levels of radon in your home, contact your state radon office for information on how to resolve the problem.
  • Test again. After you have repairs or construction done, test your home’s radon levels again to make sure you resolved the problem.
radon detector
If you are a smoker or you burn wood, coal, or other substances in your home, your risk of developing serious health problems increases.

FAQ

Q. What is radon mitigation?

A. Radon mitigation is any process used to reduce the concentration of radon gas in your home. This process can reduce radon from either the air or water supplies. Some radon mitigation systems can remove up to 99% of the radon in your home.

Q. How often should I test my home for radon?

A. You should perform a radon test when buying a new home or after performing any major renovations. If you have a mitigation system installed, it is best to perform a test once every two years. If you have no previous issues and no mitigation system installed, testing once every five years should suffice.

Q. Where should I place my radon detector?

A. According to the EPA, a radon detector must be placed in the lowest level suitable for occupancy. This would include a basement but not a crawl space. The space being tested should be a room that is regularly used, such as a living room, playroom, office, or bedroom. Do not test rooms that are used infrequently or for short periods, such as a bathroom, hallway, or laundry room.

Q. What are some symptoms I may experience if my home has an elevated level of radon?

A. Another reason it's hard to determine if you have a radon issue in your home is because the symptoms are similar to other illnesses and diseases. Symptoms can include hoarseness, a persistent cough, wheezing, chest pain, shortness of breath, frequent lung infections, fatigue, weight loss, coughing up blood, and more. If you experience any of these symptoms, especially as a chronic condition, besides contacting your doctor, consider testing the radon levels in your home.

 

Our Top Picks