Radon detectors on a white table

The 3 best radon detectors 2023 | Complete Buying Guide

Radon is a radioactive gas of natural origin whose source is in the rock and subsoil. Present in almost a quarter of French municipalities, this invisible and odourless gas infiltrates our indoor air by seeping through the foundations of our homes. Measured in becquerels per cubic metre, radon gas tends to concentrate in enclosed, unventilated spaces (cellar, basement) before rising into the house.

It is recommended that you test your home for radon if your community is identified as being at risk by the IRSN. The use of a radon detector will help you to determine the average exposure of your family to this radioactive gas. If the concentration is high, you can then proceed with renovation work such as improving the heating system, ventilation and sealing between the floor and the house.

Our comparison for the year 2023

Comparison updated on 22/03/2023

Thinking of buying a radon detector online and don't know which one to choose? Don't worry, we've got you covered.
In this article, we help you make an informed decision with the help of a clear and concise comparison. It will help you identify the product that best suits your needs, based on the opinions of many consumers.

1. RadonEye Plus Radon Detector ²

The best performer according to consumers

RadonEye is a dosimeter with a dual-structured pulsed ionisation chamber and detection circuitry that allows it to accurately assess the radon level in the air of the house after one hour of measurement. Equipped with an OLED display and mains operated, this monitoring device has an uncertainty of the displayed measurement of approximately 10 % with a deviation reduced to 1.3 % after 24 hours of testing (based on 300 Bq/m³).

Connected via Bluetooth to your smartphone, this sedentary device allows you to record long-term data (up to 1 year) and view the analysis results in graphical form via the dedicated mobile application (Android and iPhone). The RadonEye updates every 10 minutes and displays on its screen the average radon levels measured over the previous hour.

2. AirThings Wave Plus Radon Detector

Our favourite 

AirThings Wave Plus is a battery-operated dosimeter (16 months battery life). In addition to detecting radon, this product is capable of detecting CO2 level, humidity, temperature, indoor airborne chemicals (VOCs) and air pressure.

Named the 2019 TIME Magazine Invention of the Year, this indoor air quality (IAQ) monitor uses a passive diffusion chamber to determine the concentration of radon in the air in the home. With an accuracy of 5.4 pCi/L for 200 Bq/m3, the measurement uncertainty decreases over time from 10 % after 7 days of testing to 5 % after 2 months of use.

Connected to your phone via Bluetooth, the AirThings Wawe Plus displays the surrounding air quality and radon concentration via its dedicated mobile app (Android and iPhone). The device also has a visual colour indicator depending on the radon level in the air (red if ≥ 150 Bq/m3, orange if ≥ 100 and < 150 Bq/m3, green if <100 Bq/m3).

3. Corentium Home Radon Detector

An interesting price/quality ratio

Corentium Home is a battery operated dosimeter (2 years autonomy). It is easy to use, displays both short and long term readings of your radon levels and requires only 24 hours of measurement before it can present its first reliable results.

Equipped with an LCD display, the Corentium uses a passive diffusion chamber to determine the concentration of the gas in the air in the home. With an accuracy of 5.4 pCi/L for 200 Bq/m3, the measurement uncertainty of this product decreases over time from 10 % after 7 days of testing to 5 % after 2 months of use.

How does a radon detector work?

A radon dosimeter consists of a holder with or without an accumulation chamber and a detector. This device can be a nuclear trace detector (NTD), electret or alpha spectrometer.

Solid State Nuclear Trace Detectors (SSND)

A solid state nuclear trace detector is composed of a polymer that is sensitive to alpha particles. When alpha particles come into contact with the polymer (cellulose nitrate, polycarbonate, etc.), they transfer their energy by ionising or exciting the atoms of the polymer. This energy is transferred to the medium through which it passes, leaving behind areas of damage known as "latent traces". A laboratory analysis by optical microscopy following the application of a chemical treatment reveals these traces. Depending on their number, it is possible to determine the average volume of radon to which the polymer has been exposed.

There are 2 types of solid state nuclear trace detectors:

  • So-called "open configuration" devices: these products are sensitive to the presence of short-lived radon progeny and must be subjected to an equilibrium factor in accordance with the NF M 60-763 standard. This factor makes it possible to limit interpretation errors concerning the analysis of the potential alpha energy by volume.
  • So-called "closed configuration" devices: these products consist of a detection chamber that only allows radon diffusion. Once the influence of the progeny is removed, it is no longer necessary to subject the results to an equilibrium factor.

Electret detectors

An electret detector consists of a chamber of conductive plastic material, a defined detection volume and a disc of dielectric material made of polyethylene tetrafluoride. On entry, the radon passes through a filter that stops the various aerosols and its progeny.

Radon quantification is performed by raising the positive potential of the electret to several hundred volts, which creates an electrostatic field that causes the air to ionise. The electrons produced are then collected on the electret whose potential decreases. The choice of the electret/chamber pair is made by the operator and must comply with a number of measures defined by the AFNOR NF M60-766 standard.

Electronic detectors with alpha spectrometry

An electronic alpha spectrometer detector is a product with a passive scattering chamber that allows it to calculate the volume of radon in the air. The use of silicon photodiodes allows it to quantify the energy released by the alpha particles from the radon decay chain. This type of instrument is calibrated by an accredited laboratory.

What is radon?

2 minutes all inclusive | Radon

Radon-222 is a gas with an estimated lifetime of 3.82 days that is part of the radioactive decay chain of Uranium-238.

As uranium decays, it creates a solid particle of Radium 226 which in turn releases radon particles as it decays. Radioactivity is only released when this gas decays It is then transformed into Polonium 218, a radioactive element that can cause serious damage to the living tissue it encounters (cells, DNA).

As Polonium-218 decays, it in turn generates a range of metallic radionuclides, including lead-214, bismuth-214 and polonium-214, leading to (stable) lead-206.

Uranium 238 decay chain :

238α→ 234Th β→ 234Pa β→ 234α→ 230Th α→ 226Ra α→ 222Rn α→ 218Po α→ 214Pb β→ 214Bi β→ 214Po α→ 210Pb β→ 210Bi β→ 210Po α→ 206 Pb (stable)

Where does radon come from?

Radon is a naturally occurring radioactive gas found in certain rocks such as granite, acidic volcanic rocks or gneiss. It is present at relatively low levels in outdoor air, this gas enters the atmosphere after migrating from underground and tends to concentrate to a greater or lesser extent in water and enclosed areas in contact with the ground.

By taking into account the uranium content of the underlying soil, the radon potential of geological formations can be determined. By knowing the composition of our soils, it is therefore possible to determine the risk of finding this gas in our homes and in the water we consume.

Why is radon dangerous?

Radon is a gas with a long enough lifetime to be inhaled (3.82 days). When it decays, its solid progeny can settle in the lungs and lead to the development of cancer in the long term.

Second most common cause of lung cancer after smoking (but ahead of asbestos), this gas is responsible for about 9.8 % of lung cancers in non-smokers. This risk is multiplied by 3 in people exposed to radon and tobacco smoke.

Harmless in the open air (as the concentration is too low), radon becomes a health hazard in confined/poorly ventilated spacesThis is because the risk of developing lung cancer is proportional to exposure. For example, recent studies show that there is a significant risk of developing cancer from 30 years of exposure to a concentration level of 200 Bq/m3 in household air, rather than spending a few hours in a building with a very high level.

Lung cancer: the main causes (cigarette smoke, passive smoking, pollution and radon gas)

What is the radon threshold that should not be exceeded?

According to the World Health Organization (WHO), a threshold of 100 Bq/m3 is recommended, while France sets this threshold at 300 Bq/m3. The becquerel (Bq) is the metric unit that determines the activity (number of disintegrations per second) of radioactive material.

What does the French regulation say?

In France, establishments open to the public are subject to special monitoring. Every ten years, hospitals, retirement homes, schools, etc. must determine the radon concentration in their premises. If the concentration exceeds a pre-established threshold, work must be undertaken to protecting health of the occupants.

The legislation also provides for the protection of professionals working in underground environments (caves, railway or road tunnels, etc.). In this sense, every 5 years, companies are obliged to carry out measurements to determine the radon concentration in the basements they operate.

Recently, the decree 2018-434 of 4 June 2018 has enabled radon to be better taken into account extending the monitoring of establishments open to the public to include nurseries, and lowering the management threshold to 300 Bq/m3 instead of 400 Bq/m3. In addition, information must now be provided to purchasers or tenants in areas with significant radon potential.

Where can you find radon in France?

Map of radon potential in France (source: ISRN 2017)
Source: IRSN, 2017 | Figure 1149: Radon potential of geological formations in 2017 Processing | SDES, 2019

A map is made available by the IRSN (Institut de Radioprotection et de Sûreté Nucléaire) and classifies the radon potential of each municipality into 3 categories. This list of municipalities is defined in the decree of 27 June 2018 on the delimitation of radon potential zones in France.

In metropolitan France, almost a quarter of the municipalities are concerned by a medium or high level of radon potential in their subsoil, because the geological formations in part of their territory contain particularly high levels of uranium.


In the areas concerned, it is the individual houses that are mainly exposed to radon, as they are in direct contact with the subsoil. Thus, there are no less than 2.5 million people exposed to an environment with medium or high radon potential.

The most affected departments include: Haute-Corse, Corse-du-Sud, Haute-Vienne, Corrèze, Creuse, Cantal, Lozère, Haute-Loire, Loire, Morbihan, Finistère, Doubs, Ariège, Hautes-Pyrénées, Côtes-d'Armor, Calvados, Haute-Marne, Vosges, Haute-Saône and Territoire de Belfort.

Overseas, the most exposed territories are the volcanic formations of Mayotte and French Polynesia and the granite massifs of French Guyana.