Aranet Radon Plus vs Airthings Corentium Home: which is better for you?

Aranet's datasheet describes the Aranet Radon Plus's detector as alpha decay event detection with an ionization chamber, filled by air diffusion. There is no pump: air drifts into a 137 cm³ chamber through a spunbound polyester filter that keeps out radon's decay products, and Aranet rates the counting efficiency at 1 count per minute at 2.3 pCi/L. The same table says plainly that the sensor has no radon and thoron discrimination.

Airthings describes the Corentium Home's radon sampling as a passive diffusion chamber and its detection method as alpha spectrometry. Air drifts in on its own, and the sensor counts the alpha particles that radon and its decay products give off. Neither device sends anything to a laboratory; Airthings points out that the Corentium Home has no lab fees.

Ionization chamber

A chamber in which the alpha particles from radon decay ionize the air, and the detector counts each decay event. Aranet notes that, like every detector of this kind, its chamber slowly collects long-lived decay products that can add counts over years of very high exposure.

The Aranet Radon Plus shows a first number about 10 minutes after the batteries go in, and Aranet says full measurement accuracy takes 1 hour. A switch on the side moves the E-Ink screen between the 10-minute reading and the 24-hour, 7-day and 30-day averages; if the device has not run as long as the chosen average, a status mark says so. The screen also shows temperature, relative humidity, battery level and a colored threshold bar. Bluetooth links it to the free Aranet Home app for history, trends and alerts, the device keeps 30 days of history for the app to collect, and Aranet says no registration is needed and the sensor works as a standalone device.

The Corentium Home's screen is the whole interface. Airthings describes it as a simple, always-on radon detector with short-term and long-term radon levels on an integrated LCD display, and it has no Bluetooth, Wi-Fi or app. C-NRPP's list gives its first reading as taking 24 hours. Airthings adds that you can generate a radon self-inspection report to document or share your readings.

Both run on batteries, so either can sit in a room with no outlet. The Aranet Radon Plus takes two AA batteries, alkaline in the box and lithium supported. Aranet's datasheet gives 5.1 years on alkaline cells with Bluetooth off and 3.3 years with it on, and 7.1 and 4.5 years on lithium cells, figures it calls mathematical extrapolations at 68°F, provided for descriptive purposes only. The Corentium Home runs on three AAA alkaline batteries, which Airthings rates for 2 years.

The Aranet Radon Plus needs a little care. Its datasheet warns that the sensor is sensitive to static electricity, so rubbing it can briefly produce false high readings; it is rated IP20, and condensation or direct contact with water may degrade its accuracy. Sunlight can damage the E-Ink screen. Airthings gives the Corentium Home an operating range of 39 to 104°F with relative humidity below 85%.

Both models were approved in C-NRPP's 2024/25 consumer monitor evaluation, which put each device through four rounds of testing in four different sets of conditions, and both graded A in all four rounds. C-NRPP lists the Aranet as the Aranet RN+, and Aranet's quick start guide shows the Radon Plus appearing in its app as AranetRn+, so the names line up. C-NRPP tested Canadian-market units; we have not confirmed that the US versions are identical.

Neither took part in the 2024 field study that ran consumer monitors beside a calibrated reference instrument at a natural radiation laboratory in Salamanca, Spain, in the summer of 2023, so there is no field result for either. That is a fact about which monitors took part, not a result for either one.

C-NRPP grade

C-NRPP grades each round by how far a monitor's reading was from the chamber's known radon level: A for an error of 10% or less, B for more than 10% and up to 20%, and so on down to E. Accuracy results explained sets out every monitor's grades.

On the independent record the two are level: C-NRPP approved both with an A in every round. So the pick turns on how you will use it. Each row below follows from what Aranet, Airthings and C-NRPP state, and each monitor gets three.

Each has its own page with every specification and its evidence box: Aranet Radon Plus and Airthings Corentium Home. Aranet's other radon model is on the Aranet Radon One page, the Corentium Home is set beside its successor on Corentium Home vs Corentium Home 2, and every monitor we cover is on best radon monitors.

1. 1Step 1 of 5:

   Pick the floor

   The lowest lived-in level of the home, such as a basement or ground floor, in a room used regularly, not a kitchen, bathroom or laundry room.

2. 2Step 2 of 5:

   Pick a room people use

   A room occupied for at least 4 hours each day.

3. 3Step 3 of 5:

   Set the height

   At least 20 inches above the floor, away from drafts, high heat, high humidity and exterior walls.

4. 4Step 4 of 5:

   Keep the Aranet out of the sun and the damp

   Aranet asks for a spot away from direct sunlight and humid areas, and warns that rubbing the sensor can briefly push the reading up.

5. 5Step 5 of 5:

   Give it time

   At least 3 months, preferably in the heating season, and decide on the long-term average. With less than 91 days of data, follow up with a long-term test. The Aranet's screen stops at 30 days, so its app's history carries the longer picture.

More on placement is at where to place a radon test, and on reading the result at continuous radon monitors.