Products

X-Sense XR0B-SR: battery digital radon monitor with an alarm

Name: X-Sense XR0B-SR
Brand: X-Sense

By Radon411 Editorial TeamUpdated October 2, 20265 min readHow we research

Short answer

The XR0B-SR is X-Sense's battery radon detector with a built-in alarm: three AA batteries, a passive diffusion chamber read by continuous alpha spectrometry, and an LCD screen that pairs a long-term average with rolling 1, 7, 30 and 90-day averages. It was not included in C-NRPP's 2024/25 evaluation.

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At a glance

Type: Continuous monitor, battery, display and alarm, alpha spectrometry
How it measures: Continuous alpha spectrometry, passive diffusion chamber
First reading: Within 24 hours
Reading updates: Short-term averages update every hour and the long-term average every 24 hours; first reading within 4 to 24 hours
Display and app: Built-in display
Power: Battery: 3 AA alkaline batteries, replaceable, pre-installed
Units: pCi/L or Bq/m³, switchable
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 X-Sense XR0B-SR.

X-Sense product page Amazon listing

What it is and how it works

X-Sense lists the sampling method as a passive diffusion chamber and the measurement method as continuous alpha spectrometry. Air drifts into the chamber through an intake on the side of the case, with no fan or pump, and the sensor counts the alpha particles given off as radon and its decay products break down. X-Sense rates its sensitivity at 1.25 counts per hour for each pCi/L, or for each 37 Bq/m³.

Counting a small number of decays takes time, which is why the first number is not instant. After the batteries go in or the insulating film is pulled, the device runs a self-check, then shows run in place of the averages while it collects its first stable data. The manual says the first reading appears within 4 to 24 hours, sooner at higher radon levels, and that in most homes the first reliable reading comes in 24 hours.

The screen is organized around two kinds of number. The long-term average, which the manual calls the main data, is the average of everything measured since power-on or the last reset; it updates every 24 hours and can run for up to 999 days. The short-term display, which the manual calls auxiliary, rolls through averages for the past 1, 7, 30 and 90 days, and those update every hour. A trend arrow shows whether radon has recently risen, fallen or held steady.

The XR0B-SR also watches its own surroundings. It shows ranges for temperature and humidity rather than exact readings, and raises a warning icon when either passes a built-in limit. X-Sense describes a temperature and humidity algorithm as part of its accuracy, and gives an operating range of 14 to 122°F (-10 to 50°C) at up to 85% relative humidity, non-condensing.

The alarm is what sets it apart from a plain monitor. When the radon concentration passes the device's threshold, the screen flashes with a maintenance-recommended icon, the light flashes red every 10 seconds and the device beeps. A press of the Peak Level/Silence button mutes it, and the warning clears on its own once levels drop. The same button, pressed once at other times, shows the highest radon level in the current interval.

Results stay on the device. It can store up to 99 built-in reports, which a reset does not erase, and X-Sense's web page turns readings you type in, together with a 4-digit verification code from the device, into a PDF report for your phone or computer. Radon can be shown in pCi/L or Bq/m³; the manual names pCi/L as the standard unit for the United States.

Independent evidence

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 X-Sense XR0B-SR. 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.

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

X-Sense states an accuracy and precision of under ±10% at 5.4 pCi/L (200 Bq/m³) after 7 days, at 95% confidence.
X-Sense states that reliable data is obtained within 4 to 24 hours, faster at higher concentrations, and recommends testing for at least 7 days.
X-Sense states a detection range of 0 to 500 pCi/L, or 0 to 9,999 Bq/m³.
X-Sense states a battery life of 2 years and a warranty period of 5 years.

These are X-Sense'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 an audible alarm when radon climbs, not just a number to check.
You want a battery device you can move from room to room, resetting it for each new room.
You want a long-term average and recent averages on the screen without a phone or account.
You want a PDF record of a test made from the device's own data.

Look elsewhere if

You want a device that took part in C-NRPP's 2024/25 evaluation.
You want readings sent to your phone automatically; reports here are made by entering data by hand.
You want exact temperature and humidity readings; this one shows ranges.
You need a result for a home sale; check what your state accepts before relying on any consumer monitor.

Setup and placement

There is no pairing or account. Pull the insulating film from the battery compartment and the detector powers on, checks itself and starts monitoring. X-Sense recommends a single monitoring period of more than 7 days, and the manual says the long-term average means something only after at least 7 days. Leave the side air intake clear and keep the device still while it measures.

X-Sense's placement rules: measure in the basement or the lowest livable floor, where radon most often enters and builds up, or in other rooms in regular use, including rooms being finished for later use. Keep it at least 3 feet (90 cm) from the nearest door, window or air vent. Do not put it in closets, cabinets, sumps, crawl spaces or nooks in the foundation, near heat sources or drafts, in bathrooms, laundry rooms or kitchens where humidity can pass 85%, or outdoors. Keep it away from natural stone such as granite countertops, hearths and slate pool tables, and run the test while the heating system is running.

The EPA's guidance for any home test agrees on the basics: the lowest lived-in level, 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. C-NRPP asks more of a consumer monitor than X-Sense's 7 days: a room occupied for at least four hours a day, and at least three months of monitoring, ideally in the heating season.

Keep it powered. The manual advises against leaving it without batteries for more than 4 hours, because the data may become distorted and a retest would be needed. A dead or removed battery does not erase the record by default: when power comes back, recording resumes from the last saved data. Holding the Reset button for 3 seconds clears all data except the built-in reports, so do that only when starting a new monitoring cycle, such as in a new room.

Reading the result: X-Sense's own table pairs a long-term average at or above 4 pCi/L with consulting a professional, 2 to 4 pCi/L with ventilation and monitoring, and 2 pCi/L or less with no obvious problems, and adds that there is no completely safe level of radon. The EPA says to fix a home at 4 pCi/L or more and to consider fixing between 2 and 4 pCi/L, and the guidance is to decide from the long-term average.

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

The box holds the radon alarm with three removable AA batteries already installed, five date stickers for writing down when a test started, and an indicator label. X-Sense states a warranty period of 5 years.

No lab fee and no subscription. The ongoing cost is three 1.5 V AA alkaline batteries, which X-Sense rates for about 2 years; the manual says rechargeable batteries are not allowed and that batteries of different types or ages should not be mixed. The screen warns when the battery is low.

The detector itself has a limited service life, so it is a device you eventually replace rather than keep for good. When it is about to shut down, whether from a low battery, a fault or reaching the end of its service life, the manual says a data report is saved automatically, so the record is not lost.

Compared with similar products

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

X-Sense XR0B-SR (this page)
Type
Continuous monitor
How it measures
Continuous alpha spectrometry, passive diffusion chamber
Power
Battery
C-NRPP 2024/25
Not included
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 the same sensing principle, alpha spectrometry; adds Bluetooth to the Airthings app. Also not part of C-NRPP's 2024/25 evaluation.
Ecosense EcoBlu
Type
Continuous monitor
How it measures
Pulsed ionization chamber
Power
Plug-in
C-NRPP 2024/25
Not included
A plug-in monitor with an LED number display and an alarm you set to your own radon level; it uses a pulsed ionization chamber and needs an outlet rather than batteries.
Ecosense RadonEye RD200
Type
Continuous monitor
How it measures
Pulsed ionization chamber
Power
Plug-in
C-NRPP 2024/25
Approved
A plug-in monitor with a Bluetooth app and a pulsed ionization chamber, approved in C-NRPP's 2024/25 evaluation.

X-Sense XR0B-SR beside neighbouring products of the same type
Product	Type	How it measures	Power	C-NRPP 2024/25	The difference that matters
X-Sense XR0B-SR (this page)	Continuous monitor	Continuous alpha spectrometry, passive diffusion chamber	Battery	Not included	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 the same sensing principle, alpha spectrometry; adds Bluetooth to the Airthings app. Also not part of C-NRPP's 2024/25 evaluation.
Ecosense EcoBlu	Continuous monitor	Pulsed ionization chamber	Plug-in	Not included	A plug-in monitor with an LED number display and an alarm you set to your own radon level; it uses a pulsed ionization chamber and needs an outlet rather than batteries.
Ecosense RadonEye RD200	Continuous monitor	Pulsed ionization chamber	Plug-in	Approved	A plug-in monitor with a Bluetooth app and a pulsed ionization chamber, approved in C-NRPP's 2024/25 evaluation.

Every continuous monitor we cover is listed on continuous monitors.

Questions people ask

Is the X-Sense XR0B-SR C-NRPP approved?

It was not included in C-NRPP's 2024/25 consumer monitor evaluation, so there is no result for it from that round. That says nothing either way about how it measures; it was simply not one of the devices tested.

How long before it shows a radon number?

The screen shows run until the first stable data is ready, which the manual puts at 4 to 24 hours depending on the radon level, and about 24 hours in most homes. The long-term average needs at least 7 days before it is worth reading.

What sets off the alarm, and can I turn it off?

The alarm sounds when the radon concentration passes the device's built-in threshold. One press of Peak Level/Silence mutes the current warning, and the warning clears on its own when radon falls. In settings mode, the audio and visual indicators can be switched off altogether; they are on by default.

The alarm is a prompt, not a verdict. The manual itself says to check the long-term average if concerns remain when no alarm has sounded, and the EPA's advice is to confirm a high result with a follow-up test before deciding to fix a home.

Can I use it to test more than one room?

Yes. X-Sense lists one-button reset for multi-room monitoring. Holding Reset for 3 seconds clears the data and starts a new cycle, while the built-in reports from earlier rooms are kept. The date stickers in the box are for noting when each test began.

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

For any consumer monitor, the guidance is to run it for at least three months, preferably in the heating season, and to decide from the long-term average. If you have less than 91 days of monitor data, it recommends following up with a long-term radon test. The XR0B-SR's long-term average can run for up to 999 days, so it can cover that period.

Does it work in Bq/m³?

Yes. Double-pressing the Peak Level/Silence button switches radon between pCi/L and Bq/m³. The manual names pCi/L as the standard unit in the United States and suggests Bq/m³ for use in Europe or Canada.