What it is and how it works
The sensor, the sampling and the readings
X-Sense lists the sampling method as a passive diffusion chamber and the measurement method as continuous alpha spectrometry. Air drifts into the chamber on its own, 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 the sensor's sensitivity at 1.25 counts per hour for each pCi/L, or for each 37 Bq/m³.
That count rate explains the wait for a first number. X-Sense gives a detection stabilization time of 4 to 24 hours for reliable data, with results coming faster at higher concentrations, and recommends a testing period of at least 7 days. At the levels most homes see, plan on a day before the first figure means much and a week before you lean on it.
The screen shows two kinds of average. X-Sense lists a data update cycle of 1 hour for the short-term average and 24 hours for the long-term average, so the short-term figure follows recent changes and the long-term figure moves slowly. X-Sense describes the display as easy to read, and lists the detection range as 0 to 500 pCi/L, or 0 to 9,999 Bq/m³.
It is a standalone device. X-Sense marks it as incompatible with its SBS50 base station, so the XR0A-SR works on its own rather than through an X-Sense hub. It is built around a one-button reset for multi-room monitoring: you reset it, move it, and start a new set of averages in the next room. X-Sense also describes report generation, so you have clear data to take to an expert.
X-Sense sells a second battery detector, the XR0B-SR, which it calls a radon alarm. The two share the sampling method, measurement method, sensitivity, range, battery type and battery life that X-Sense lists, so the choice between them comes down to the features each page describes.
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 X-Sense XR0A-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's own statements, attributed
- X-Sense saysX-Sense states detection results within 24 hours, with reliable data in 4 to 24 hours and faster results at higher concentrations.
- X-Sense saysX-Sense states a detection range of 0 to 500 pCi/L, or 0 to 9,999 Bq/m³.
- X-Sense saysX-Sense states a battery life of 2 years on three replaceable AA alkaline batteries.
- X-Sense saysX-Sense states 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, and look elsewhere if
Good fit if
- You want a battery detector you can reset and move from room to room.
- You want short-term and long-term averages on a screen, with no hub to set up.
- You want a sensor of the alpha spectrometry kind that counts radon continuously.
- You want a warranty period of several years on the device.
Look elsewhere if
- You want a device that was itself graded in C-NRPP's 2024/25 evaluation.
- You want it to work with an X-Sense SBS50 base station; X-Sense marks it as incompatible.
- You want a number within minutes; reliable data takes 4 to 24 hours.
- You need a result for a home sale; check what your state accepts before relying on any consumer detector.
Setup and placement
4 steps
- X-Sense's operating conditions are 14 to 122°F (-10 to 50°C) at up to 85% relative humidity, non-condensing, so a damp corner of an unfinished basement is not the place for it. It measures 3.23 by 3.15 by 2.79 inches (82 by 80 by 70.8 mm) and weighs 10.3 oz (292 g), small enough for a shelf or table.
- The EPA's general placement guidance applies to any radon test: 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. Give it the 7 days X-Sense recommends before reading much into the averages.
- To compare rooms, reset it each time you move it and let it run again for the same length of time, so each room's long-term average covers a similar stretch. If you want a record of each room, write down its averages before you press reset.
- 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 less than 91 days of data, it recommends a follow-up long-term test. The EPA's guidance is to fix a home at 4 pCi/L or more and to consider fixing between 2 and 4 pCi/L.
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
Contents, warranty and running costs
In the box
X-Sense lists the power supply as three replaceable 1.5 V AA alkaline batteries and gives a warranty period of 5 years. X-Sense's store offers it singly and as a 2-pack, which suits testing two floors at once.
Running costs
There is no lab fee, hub or subscription. The running cost is three AA alkaline batteries, which X-Sense rates for 2 years. Because it is a standalone detector, there is nothing else to buy for it to work.
Questions people ask
5 questions, answered
How long does the XR0A-SR take to give a reading?
X-Sense gives 4 to 24 hours for reliable data, faster at higher radon levels, and recommends testing for at least 7 days. The short-term average then updates every hour and the long-term average every 24 hours.
What is the difference between the XR0A-SR and the XR0B-SR?
X-Sense lists the same sampling method, measurement method, sensitivity, range and batteries for both. The XR0B-SR is sold as a radon alarm, with a built-in alarm and rolling 1, 7, 30 and 90-day averages; the XR0A-SR is the standalone detector with short-term and long-term averages and a one-button reset.
Does the XR0A-SR work with the X-Sense SBS50 base station?
No. X-Sense marks it as incompatible with the SBS50 base station; it is a standalone detector, with its readings on its own screen.
Is the XR0A-SR 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.
How long do the batteries last?
X-Sense rates three replaceable AA alkaline batteries for 2 years, and gives a warranty period of 5 years for the detector.
What to do next
- See every continuous monitor we coverEach with the same fields and its evidence.Go
- Place it where it countsThe lowest lived-in level, away from drafts, at least 20 inches up.Go
- Read your resultWhat a number in pCi/L means and what the EPA says to do next.Go
- Testing for a home sale?Find radon measurement professionals in our directory.Go