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RADON411

Airthereal

Airthereal RM-65

Rechargeable radon detector with a color screen and alarm

  • Monitor
  • Battery
  • Screen
  • First reading in 6 hours
C-NRPP 2024/25 evaluation: Not includedSee the evidence
  • Airthereal RM-65
  • Airthereal RM-65, photo 2 of 4
  • Airthereal RM-65, photo 3 of 4
  • Airthereal RM-65, photo 4 of 4

Photos: Airthereal

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  • PowerBattery
  • ReadingsScreen
  • First reading6 hours
  • C-NRPP 2024/25Not included
  • Every figure checked against the specifications Airthereal publishes
  • Independent test results shown the same way for every product, unranked
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About this item

As Airthereal states it

  • How it measures: Semiconductor radon sensor counting alpha decays, with air vents on three sides for diffusion
  • First reading: Within 6 hours
  • Reading updates: Data update time 60 minutes; one data point saved every 6 hours, up to 504 days per record and up to 10 records
  • Display and app: Built-in display
  • Power: Battery: Built-in 2000 mAh rechargeable battery, charged over USB Type-C in about 3.5 hours; battery life 45 days in screen-off state
  • Units: Bq/m³ or pCi/L, selectable in Settings

The RM-65 is a small, round radon detector from Airthereal: a semiconductor sensor that counts the alpha decays of radon diffusing in through vents on three sides, a 2.0-inch color screen, a sound and light alarm, and a built-in battery charged over USB-C. It was not included in C-NRPP's 2024/25 evaluation.

What you get

The box contents are not stated by the maker: the product page's "In the Box" section holds radon fact cards rather than a list of what ships, and the manual has no contents list. Airthereal's product photos show the detector with a USB cable, and the manual names no charger. Airthereal's store lists the RM-65 under SKU 531-20-DR65.

In the box and running costs

How it works

What it measures and how

The sensor, the sampling and the readings, then who has checked it

How it works

In our words, from the maker's documents

Airthereal's manual for the RM-65 calls it a portable radon concentration monitor that watches the alpha radiation given off as radon decays, using a semiconductor radon sensor. Air reaches the sensor by diffusion, through vents on three sides of the case. Each time the sensor detects a decay, a green light on the front flashes once, and the screen keeps a running total count; the radon concentration is calculated by integrating that count over time.

The first number appears 6 hours after it is switched on, and a countdown on the screen shows how long is left. Airthereal's manual says the data becomes reliable after 6 hours when the level is above 190 Bq/m³, after 12 hours between 94 and 190 Bq/m³, and after 24 hours below 94 Bq/m³ (about 5.1 and 2.5 pCi/L), so the lower your radon, the longer it takes to settle. After that, the data updates every 60 minutes.

On the measuring screen, the arrow keys switch between the accumulated average, the 24, 48, 72 and 96-hour values and the accumulated peak, and the screen returns to the accumulated average after 50 seconds without a key press. A colored bar shows which zone the current value falls in. The Data menu holds the history: a 6-hour value for every 6-hour interval and the running average since power-on, with one data point saved every 6 hours, up to 504 days in a single record and up to 10 records. Each retest starts a new numbered record and keeps the old one.

The manual lists a measurement range of 3.3 Bq to 37 kBq/m³ (0.09 to 1000 pCi/L) and a measurement accuracy of ±15%. Readings show in Bq/m³ or pCi/L, chosen in the Unit setting, and the menus come in English or Chinese. It also lists a temperature and humidity sensor as optional, and warns that those readings may run a little high because the sensor sits inside a device that warms itself while working.

Power is a built-in 2000 mAh battery, charged through a Type-C port in about 3.5 hours with the device off; a green light stays on while it charges. The manual rates the battery life at 45 days with the screen off, a low-power state in which it keeps measuring, recording and alarming. The case is 80 mm across and 40 mm high and weighs about 123 g. Everything is read on the device itself: Airthereal's manual describes no phone app, Bluetooth or Wi-Fi.

What the manufacturer says

Airthereal's own statements, attributed

  • Airthereal saysAirthereal's manual lists a measurement accuracy of ±15% over a range of 0.09 to 1000 pCi/L.
  • Airthereal saysAirthereal states the RM-65 gives a first reading in 6 hours, 18 hours faster than traditional monitors.
  • Airthereal saysAirthereal states a 45-day runtime from the 3.7V USB-C rechargeable battery; the manual gives 45 days with the screen off.
  • Airthereal saysAirthereal states the internal memory stores up to 504 days of radon data.
  • Airthereal saysAirthereal's manual describes patented radon filtration and radon signal screening technology and an adaptive integration algorithm.
  • Airthereal saysAirthereal argues that a reasonable spread between detectors reflects real radon data, and says some low-end detectors look more consistent because they generate values only from internal algorithms.

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

Independent evidence

C-NRPP 2024/25, recalls and studies

C-NRPP 2024/25
Not included in C-NRPP's 2024/25 evaluation

The Canadian National Radon Proficiency Program's 2024/25 comparison of consumer monitors did not include Airthereal RM-65. That is a fact about which devices took part, not a finding about this one: no result from that program exists for it either way.

Recalls
No Health Canada recall or advisory names this device.
Peer-reviewed studies
We found no peer-reviewed comparison that names this model.
Notes
  • No Airthereal device appears on C-NRPP's 2024/25 consumer monitor page, report or detailed results, and no Health Canada recall or advisory names Airthereal or the RM-65 (Health Canada recalls search, 2026-10-08).

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

Specifications

Specifications

Every figure as the maker states it

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The maker's figures

Type
Continuous monitor, rechargeable, color display, semiconductor sensor, audible alarm
How it measures
Semiconductor radon sensor counting alpha decays, with air vents on three sides for diffusion
First reading
Within 6 hours
Reading updates
Data update time 60 minutes; one data point saved every 6 hours, up to 504 days per record and up to 10 records
Display and app
Built-in display
Power
Battery: Built-in 2000 mAh rechargeable battery, charged over USB Type-C in about 3.5 hours; battery life 45 days in screen-off state
Units
Bq/m³ or pCi/L, selectable in Settings

What is in the box

The box contents are not stated by the maker: the product page's "In the Box" section holds radon fact cards rather than a list of what ships, and the manual has no contents list. Airthereal's product photos show the detector with a USB cable, and the manual names no charger. Airthereal's store lists the RM-65 under SKU 531-20-DR65.

Airthereal's Warranty Product List gives the RM-65 a 1 year warranty, covering manufacturing and material defects from the date of purchase, with free replacement of defective units. The warranty page says it is non-transferable and made to the original owner when the purchase was made through an authorized supplier, defines the original purchaser as the first purchaser from airthereal.com, excludes purchases from unauthorized resellers, and asks you to keep the receipt. For a refund, it says to contact the channel you bought from.

What it costs to run

There is no lab fee and no battery to buy: the 2000 mAh battery recharges through the Type-C port. The 45-day rating is for the screen-off state, and the ECO setting decides how soon the screen sleeps, 10 minutes by default.

The manual describes no subscription, app or calibration service, and Airthereal states no sensor life for the RM-65. Out-of-warranty service is at the owner's cost: Airthereal's warranty page says that after the warranty ends you may choose to pay all labor and parts charges.

Fit and setup

Who it fits, and how to use it

The fit, then setup and placement as the guidance asks

Who it fits

Good fit if, and look elsewhere if

Good fit if

  • You want a small detector to carry from room to room, charged over USB-C rather than on disposable batteries.
  • You want a first number within hours, with 24 to 96-hour values, an accumulated average and a peak on the screen.
  • You want a sound and light alarm at a level you choose from the maker's list of thresholds.
  • You want a stored history on the device itself, with no app or account.

Look elsewhere if

  • You want a device that was itself graded in C-NRPP's 2024/25 evaluation.
  • You want an alarm below about 2.7 pCi/L; the lowest threshold the manual lists is 100 Bq/m³.
  • You want readings or alerts on your phone; the manual describes no app or wireless connection.
  • You need a result for a home sale; check what your state accepts before relying on any consumer detector.

Setup and placement

5 steps

  1. Hold the power key for 3 seconds to switch the RM-65 on: the green light comes on, the buzzer beeps once, and on the very first start it asks for the language, date and clock. It re-measures automatically each time it is powered on, and it goes straight to the measuring screen. Airthereal's store record describes it as suited to basements, homes, offices and RVs.
  2. The manual gives no placement height or distance rules. Its conditions are a working range of -14 to 113°F with relative humidity below 90%, and it says the data cannot be trusted outside that range. Above 90% humidity it suggests granular, not powdered, desiccant at the bottom or both sides of the air inlet. It asks you to avoid intense vibration, warns that the device is not waterproof, and says to charge it promptly when the battery runs low so monitoring continues.
  3. After a very high reading, radon and its decay products cling inside the detector; the manual says they take 24 hours to 3.8 days to decay, and to wait 24 to 48 hours before restarting. To begin a fresh average at any time, choose Retest in the menu; the previous data is saved as its own record.
  4. For where to put it, EPA's guidance for any home test applies: the lowest lived-in level of the home, a room used regularly but not the kitchen or bathroom, at least 20 inches above the floor, and away from drafts, high heat, high humidity and exterior walls.
  5. For a decision about fixing your home, C-NRPP's advice for any consumer monitor is to place it in a room occupied at least 4 hours a day, test for a minimum of 3 months, preferably in the heating season, and decide on the long-term average, with a follow-up long-term test if you have less than 91 days of data. EPA says to fix a home at 4 pCi/L or more and to consider fixing between 2 and 4 pCi/L. Airthereal's manual suggests ventilating for at least 10 minutes when the level passes 4 pCi/L.

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.

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

Compare

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The same three rows for each, and the one difference that matters

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Questions

Questions people ask

6 questions about the Airthereal RM-65, answered

Asked about the RM-65

How long does the RM-65 take to show a reading?

6 hours after it is switched on; until then the value shows "--". Airthereal's manual then counts the data as reliable after 6, 12 or 24 hours depending on the level, the lower the level the longer, and updates it every 60 minutes. For a decision about your home, the long-term average over months matters more than the first day.

What does the alarm do, and can I change the level?

When the reading passes the alarm limit, the red light and the buzzer go off together, and the buzzer sounds for 20 seconds every hour while the level stays over. The default threshold is 148 Bq/m³, which the manual equates to 4 pCi/L, and the Alarm setting offers 100, 148, 200, 300, 400, 600 and 800 Bq/m³. The Alarm item on the main menu turns the sound off or on quickly.

A separate particle sound, off by default, makes the buzzer beep once for every alpha decay the sensor detects, so an occasional beep with that setting on is normal.

How long does the battery last?

About 45 days per charge with the screen off, by Airthereal's manual, which gives no figure for a screen kept lit. While the screen sleeps the RM-65 still measures, records and alarms. Recharging takes about 3.5 hours with the device switched off.

Is the RM-65 C-NRPP approved?

It was not included in C-NRPP's 2024/25 consumer monitor evaluation, so there is no C-NRPP result for it either way.

Does the RM-65 work with a phone app?

Airthereal's manual for the RM-65 describes no app, Bluetooth or Wi-Fi; the readings, history and settings are all on the device's screen and keys. Airthereal's site promotes its AIR.ai app for its Wi-Fi-enabled products, and the RM-65 manual does not mention it.

Why do two detectors side by side read differently?

Airthereal's answer is that radon decays at random and spreads unevenly where air does not circulate, so two nearby detectors can differ in the short term, and that the cumulative average from continuous observation is the fairer comparison. Its manual says the same of low levels: the count can be uneven and different devices can differ slightly. Airthereal adds that a sudden surge in differences may rarely come from light leakage in one particular detector.

What to do next

Updated October 8, 2026