Products

Aranet Radon Plus: battery digital radon monitor with an e-ink screen

Name: Aranet Radon Plus
Brand: Aranet

By Radon411 Editorial TeamUpdated October 2, 20264 min readHow we research

Short answer

The Aranet Radon Plus is a battery-powered radon monitor from SAF Tehnika's Aranet line: an ionization chamber that counts alpha decay events, an always-on E-Ink screen, temperature and humidity, and Bluetooth to the free Aranet Home app. C-NRPP's 2024/25 evaluation approved it, listed as the Aranet RN+, with an A in each of its four test rounds.

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At a glance

Type: Continuous monitor, battery, Bluetooth, E-Ink, ionization chamber
How it measures: Alpha decay event detection with an ionization chamber, air diffusion
First reading: Within 10 minutes
Reading updates: Updates every 10 minutes; 24-hour, 7-day and 30-day averages on the screen
Display and app: Built-in display, phone app, Bluetooth
Power: Battery: 2 AA batteries (alkaline included; lithium supported)
Units: pCi/L or Bq/m³, selectable
Price: Not shown. We print a price only from Amazon's live product data, with the time it was checked, and that feed is not connected yet.

Drawing of a battery-powered digital radon monitor with a small display — Our drawing of this type of device, not a photo of the Aranet Radon Plus.

Aranet product page

What it is and how it works

Aranet's datasheet describes the 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, so the sensor counts the alpha particles from radon that has entered and decayed inside. Aranet rates its efficiency at 1 count per minute at 2.3 pCi/L.

The datasheet also says plainly what the sensor cannot do: it has no radon and thoron discrimination, so it cannot tell radon from thoron, a related gas. The same table gives the chamber's volume, its filter material and its counting efficiency, the figures above.

The reading updates every 10 minutes. The first number appears about 10 minutes after the batteries go in, and Aranet says full measurement accuracy takes 1 hour. A switch on the side moves the screen between the 10-minute reading and 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 published range is 0 to 214 pCi/L, or 0 to 7,900 Bq/m³, at a resolution of 0.02 pCi/L.

The screen is E-Ink, which holds its image without power and is the main reason for the long battery life. It shows radon, the averaging period, temperature, relative humidity, battery level and a colored threshold bar. The sensor also measures atmospheric pressure, but only the app shows it. Radon can be shown in pCi/L, which Aranet calls the US standard unit, or in Bq/m³.

Bluetooth links the sensor to the free Aranet Home app for history, trends and alerts. The device keeps 30 days of history for the app to collect, so the record survives if the phone is away for a few weeks. No account or registration is needed, and the sensor works on its own without the app; most settings, including the threshold colors, are changed in the app, while units, the buzzer, Bluetooth and a reset are on the device's own menu.

One long-term effect is spelled out in the datasheet. Like every ionization chamber radon detector, it slowly collects long-lived decay products such as lead-210 inside the chamber, which add counts even without radon. Aranet's own example: five years of continuous exposure at about 27 pCi/L (1,000 Bq/m³) could shift readings upward by around 4 pCi/L (150 Bq/m³). At ordinary household levels the effect is far smaller.

Independent evidence

C-NRPP 2024/25

Approved in C-NRPP's 2024/25 consumer monitor evaluation

Listed by C-NRPP as "Aranet RN+". Results published May 2025.

Grade by round

Round 1A218 Bq/m³, 23°C, 28% RH, 7 days
Round 2A210 Bq/m³, 29°C, 70% RH, 7 days
Round 3A436 Bq/m³, 23°C, 36% RH, 7 days
Round 4A1,201 Bq/m³, 23°C, 35% RH, 7 days

C-NRPP grades each round by measurement error: A is 10% or less, B more than 10% and up to 20%, C more than 20% and up to 30%. It recommends devices that average B or better.

Recalls

No Health Canada recall or advisory names this device.

Peer-reviewed studies

We found no peer-reviewed comparison that names this model.

Notes

C-NRPP tested Canadian-market units; we have not confirmed the US version is identical.

C-NRPP is the Canadian National Radon Proficiency Program. Its 2024/25 results were published in May 2025.

How C-NRPP says to use any consumer monitor

Leave it in place for at least three months, ideally through the heating season, when indoor radon tends to be highest.
Put it in a room someone uses for at least four hours a day.
Decide about fixing your home from the long-term average, not a single day or week.
If you can only run a monitor for less than 91 days, follow up with a long-term test.

What the manufacturer says

Aranet states an accuracy of ±8% for the 24-hour, 7-day and 30-day averages, and C-NRPP lists the same stated accuracy for the Aranet RN+.
Aranet states that 95% of sensors measure within its typical limits at the time of sale, and that the radon reading shows no long-term drift.
Aranet states a battery life of 5.1 years on alkaline batteries with Bluetooth off and 3.3 years with it on, and up to 7.1 years on lithium batteries, figures it describes as extrapolated rather than guaranteed.
Aranet states that the first reading appears in 10 minutes and that the 1-hour average is reliable.

These are Aranet's own statements, attributed to it. They are not our findings, and we have not tested this product ourselves.

Who it fits

Good fit if

You want a device that was approved in C-NRPP's 2024/25 evaluation.
You want a battery monitor that can sit anywhere for years without a cable.
You want numbers on the device itself, with 24-hour, 7-day and 30-day averages a switch away.
You want an app for history and alerts, but no account and no subscription.

Look elsewhere if

You want Wi-Fi, so readings reach you while you are away; this one uses Bluetooth.
You want a long-term average on the screen that runs past 30 days.
You want a plug-in monitor that never needs batteries.
You need a result for a home sale; check what your state accepts before relying on any consumer monitor.

Setup and placement

Insert the batteries with the right polarity, press the switch, and wait about 10 minutes for the first measurement. Pairing with Aranet Home is optional: in the app, choose to pair a new device, pick the sensor by the device number on its screen, and enter the pairing code the sensor shows.

Aranet's placement advice matches the EPA's: the lowest livable level, such as a basement or ground floor, at least 20 inches above the floor, away from drafts, direct sunlight and humid areas, and not in kitchens, bathrooms or laundry rooms. The datasheet adds the reasons. Sunlight can damage the E-Ink screen and affect the readings, and humidity above the operating range stops the sensor detecting radon properly, so it shows a warning until it is moved somewhere drier.

Handle it gently while it measures. The datasheet warns that the sensor is sensitive to static electricity, and that rubbing it can briefly produce false high radon readings. It is rated IP20, which gives no protection against water, and condensation or contact with water can harm both accuracy and the sensor's life.

For a decision, read the long run. For any consumer monitor, the guidance is a room occupied for at least four hours a day and at least three months of monitoring, ideally in the heating season, deciding from the long-term average. The screen's longest view is 30 days, so the app's history is where a three-month picture comes from. A reset on the device permanently erases the stored data, and Aranet suggests it only when the sensor changes hands or for a fresh start.

For where any radon test or monitor should sit in a home, see where to place a radon test.

What is in the box, and what it costs to run

Aranet lists two AA alkaline batteries in the packaging, with the sensor. It measures 2.80 by 2.80 by 3.03 inches and weighs 7.8 oz with batteries, in a polycarbonate case.

No lab fees, no subscription and no registration. The only running cost is two AA batteries every few years: Aranet's figures are about 5 years on alkaline cells with Bluetooth off and about 3 with it on, longer on lithium cells, and turning on the app's extended Bluetooth range shortens them.

Compared with similar products

This product first, then its neighbors A to Z. Order is not a recommendation.

Aranet Radon Plus (this page)
Type
Continuous monitor
How it measures
Alpha decay event detection with an ionization chamber, air diffusion
Power
Battery
C-NRPP 2024/25
Approved
Airthings Corentium Home 2
Type
Continuous monitor
How it measures
Alpha spectrometry, passive diffusion chamber
Power
Battery
C-NRPP 2024/25
Not included
Also battery-powered with a screen of averages and a Bluetooth app, using alpha spectrometry; it was not part of C-NRPP's 2024/25 evaluation.
Airthings View Radon
Type
Continuous monitor
How it measures
Alpha spectrometry, passive diffusion chamber
Power
Battery
C-NRPP 2024/25
Approved
Also approved by C-NRPP in 2024/25, and also battery-powered with an ePaper screen, but it adds Wi-Fi and can run on a USB cable.
Ecosense RadonEye RD200
Type
Continuous monitor
How it measures
Pulsed ionization chamber
Power
Plug-in
C-NRPP 2024/25
Approved
Also approved by C-NRPP in 2024/25 and also uses an ionization chamber with a Bluetooth app, but it plugs into an outlet rather than running on batteries.

Aranet Radon Plus beside neighbouring products of the same type
Product	Type	How it measures	Power	C-NRPP 2024/25	The difference that matters
Aranet Radon Plus (this page)	Continuous monitor	Alpha decay event detection with an ionization chamber, air diffusion	Battery	Approved	The product this page covers.
Airthings Corentium Home 2	Continuous monitor	Alpha spectrometry, passive diffusion chamber	Battery	Not included	Also battery-powered with a screen of averages and a Bluetooth app, using alpha spectrometry; it was not part of C-NRPP's 2024/25 evaluation.
Airthings View Radon	Continuous monitor	Alpha spectrometry, passive diffusion chamber	Battery	Approved	Also approved by C-NRPP in 2024/25, and also battery-powered with an ePaper screen, but it adds Wi-Fi and can run on a USB cable.
Ecosense RadonEye RD200	Continuous monitor	Pulsed ionization chamber	Plug-in	Approved	Also approved by C-NRPP in 2024/25 and also uses an ionization chamber with a Bluetooth app, but it plugs into an outlet rather than running on batteries.

Every continuous monitor we cover is listed on continuous monitors.

Questions people ask

Is the Aranet Radon Plus C-NRPP approved?

Yes. C-NRPP's 2024/25 evaluation of consumer monitors lists the Aranet RN+ as approved, and its detailed results show an A in each of the four test rounds. Aranet's datasheet gives the Radon Plus one product number worldwide, TDSPSRH2.

Is the RN+ the same device as the Radon Plus?

The names line up: C-NRPP lists the Aranet RN+, and Aranet's own quick start guide shows the Radon Plus appearing in the app as AranetRn+ followed by its device number.

What do the green, yellow and red bars mean?

By default, green is under 2.7 pCi/L (100 Bq/m³), yellow is 2.7 to 8.1 pCi/L, and red is above 8.1 pCi/L (300 Bq/m³), thresholds Aranet bases on the World Health Organization's radon guidance. They can be changed in the Aranet Home app.

Those defaults are not the US levels. The EPA says to fix a home at 4 pCi/L or more and to consider fixing between 2 and 4 pCi/L, so a US household may want to move the thresholds to match.

Does it need Wi-Fi or a subscription?

Neither. It uses Bluetooth, works as a standalone device, and Aranet says it needs no registration, subscription or recurring fees. The app adds history and alerts when your phone is in range.

How long do the batteries last?

Aranet's datasheet gives 5.1 years on alkaline batteries with Bluetooth off and 3.3 years with it on, and 7.1 and 4.5 years on lithium batteries. It calls the figures mathematical extrapolations at 68°F, provided for description only.

Can the 30-day average stand in for a long-term test?

Not on its own. C-NRPP recommends at least three months of monitoring, preferably in the heating season, and a follow-up long-term test if you have less than 91 days of monitor data. Keeping the app's history over that period gives the longer picture the screen does not.