Aranet Radon Plus Review – The Most Convenient Radon Monitor

Despite running this website for almost five years now and having reviewed many air quality monitors, there’s one pollutant I’ve never really focused on. I’ll give you a second to guess what that is… Don’t have a second? Fair enough. It’s radon. In fact, I’ve only covered one monitor that even includes radon, the Airthings View Plus. 

There is no particular reason that I haven’t covered radon monitors, but I just haven’t felt the need to cover them. However, I was instantly interested when Aranet approached me to ask if I would be interested in trying their new Aranet Radon Plus monitor. I first used the Aranet4 Home CO2 monitor a couple of years ago, and since then, I’ve also acquired an Aranet2 and an Aranet Radiation monitor. I’ve become somewhat of a fan of Aranet, and this offer felt like a natural time to cross over into the world of radon monitoring. 

Since I didn’t want to test a radon monitor in isolation (as that would give me no point of comparison for this review), I also purchased some of the most popular radon monitors on the market – namely, the EcoQube, RadonEye, and Airthings Corentium. Each of these monitors has distinct strengths and disadvantages, and I’ve spent the past month trying all of the features on each. While I will be writing full reviews of each monitor in due time, today, I want to focus on the new Aranet Radon Plus. 

The Aranet Radon Plus is the most costly sensor in the Aranet Home lineup. It’s also the only sensor that departs from the typical compact form factor of the other Home devices. While it’s still small, the size needed to be increased to house the ionisation chamber needed to monitor the radon concentration. However, despite this design departure, the Radon Plus shares many of the other Home monitors’ strengths. 

In today’s review, I will explore the Aranet Radon Plus in-depth, discussing how it works, whether or not it’s accurate, and aspects such as connectivity and design. If you’re considering purchasing the Aranet Radon Plus, I hope this review can help guide you in the right direction. With that said, let’s dive right in!

This post contains affiliate links. For more information, please refer to my affiliate disclaimer. I was sent a product for review, but the article is not sponsored. All opinions expressed in this post are my honest thoughts. I only recommend products that I genuinely believe in.

Information on this blog is for informational purposes only. Readers are encouraged to confirm the information herein with other sources. Furthermore, this information is not intended to replace medical advice from professionals. This website assumes no responsibility for the accuracy of the information, and information is subject to change without notice. Devices mentioned on this website are not medical devices and do not guarantee protection.

Sensor & Accuracy

This is my first time writing about a radon monitor on this blog, so I will rely more on the official specifications than usual. While I always emphasise third-party testing, this is much more difficult with low-cost radon monitors as a reference device is pricey, and there are few official certifications for such devices. I have been told that Aranet is seeking certifications for this device, but at the time of writing this review, the device is still very new and doesn’t yet have these. If you’re reading this review significantly after the release, I recommend checking the Aranet Home website to see if this is still true.

Before even looking at the Aranet device, I was curious if consumer-grade radon monitors (not certified by a body like NRPP) are accurate. Through my research, I found research from the C-NRPP (the Canadian National Radon Proficiency Program) showing that, yes, most reputable consumer-grade monitors do perform within their specified accuracy ratings.

Read the full report here.

While the Aranet device has not yet been tested, this is a good start! These monitors perform within their stated accuracy (which is usually within ≤ 10% of the actual reading, shown as an A in the table above), and while likely expected, I’m glad to see these results. While accuracy will decrease over time (which I will discuss in more detail soon), it’s good to see consumer-grade radon sensors in a state where they’re generally accurate enough to be useful.

Low-cost radon sensors ( < $300) can use one of a couple of methods to monitor radon levels; each has advantages and disadvantages. Below are the main methods used in these low-cost monitors (with an example of which monitor uses each method):

Photo Diode Alpha Spectrometry:

• Advantage: Offers fast response times.
• Disadvantage: Sensitive to environmental factors like humidity, requiring compensation.
• Airthings (View Plus, View Radon, Wave Plus)

Pulsed Ionization Chamber:

• Advantage: Highly energy-efficient and high accuracy.
• Disadvantage: Lower sensitivity than standard ionization chambers, affecting precision.
• EcoQube, RadonEye

Some devices may also use continuous ionization chambers, but I can’t find any consumer-grade monitors that use this method. These devices work similarly to pulsed ionization chamber devices, but they continuously measure the radon levels. This means they consume more power but are also more sensitive and will respond more quickly to radon trends. However, they’re also more susceptible to drift due to radon progeny buildup.

Radon measurements from the condo I am staying in.

The Aranet Radon Plus uses a pulsed ionization chamber that has been developed in-house, meaning this is a unique radon sensor that you can’t find in any other monitors (as opposed to some other brands, which use components from sensor manufacturers). From what I’ve been told, this sensor has been designed to provide incredible battery life, which is a statement that often concerns me as this can mean infrequent readings and be detrimental to accuracy. However, we will discuss this in more detail soon.

Let’s look at the official specifications of the Aranet Radon Plus from Aranet themselves. One thing I appreciate about its in-depth datasheet is how it provides more detail on the sensor’s performance than many competing brands. Through research, I’ve found that most brands provide only a sensor type and accuracy specification. However, even these typically aren’t very transparent (more on that soon). Here are the official specs of the Aranet Radon Plus, but please refer to the linked datasheet for more information.

The monitor also offers averages for the past 24 hours, 7 days, and 30 days alongside the current concentration. These different averages all hold the same ±8% accuracy rating, but they should provide more reliable results if the monitor is static (in the same location) for the averaging period by better accounting for outliers and trends. The device must be left on for one hour to get accurate readings. While the exact period differs from monitor to monitor (some require 10 minutes, while some require longer than 24 hours), this is common and expected with radon monitors.

While the first ‘accurate reading’ is said to be provided quite quickly (not just with this monitor but with many), the C-NRPP recommends waiting a much longer period before really trusting the readings shown by a device like this. In fact, they recommend waiting at least three months before acting on the readings provided by a radon monitor. While this is a very long time, it’s for good reason.

Why is this the case? Well, it’s for a couple of reasons. Firstly, radon levels naturally fluctuate, and a device takes time to capture a representative sample that reflects an accurate concentration. For this reason, even professional-grade radon monitors and tests can take days or months to gather data. It’s also for this reason that the longer averaging periods on the Aranet Radon Plus are a better indication of your true radon concentration (as long as the device isn’t moved).

Furthermore, since radon monitors measure progeny (radioactive decay products of radon gas), which emit radiation, they can’t take measurements instantly. Instead, there must be enough time for decay products to accumulate within the ionization chamber to be measured. Some monitors also require time to calibrate and account for other environmental factors that can influence readings. These factors combined mean that all radon test kits and monitors take time to get accurate readings.

Where most monitors in the same price range state their accuracy as ±10%, I appreciate Aranet stating the accuracy as ±8%, but only for 95% of readings. As mentioned, there is inherent error with these kinds of sensors, and there is always a level of uncertainty. If Aranet were to expand the accuracy to, say, ±10% as well, even this would only apply to (this is a total guess) 98% of readings. The same applies to other radon sensors, but most manufacturers don’t state the uncertainty of their sensors.

Learning about radon progeny also made me curious about the sensor’s long-term drift. While the battery life can last up to 7 years, can the sensor actually remain accurate for that long as more decay products accumulate within it? Well, I’ve been told that there is no drift regarding the sensor’s sensing capabilities, but this accumulation of radon decay products in the sensing chamber (such as Pb-210) can continue to release radiation even when no new radon is present, leading to long-term drift.

This buildup depends on how much radon the detector is exposed to over time, and it’s challenging to predict precisely. Aranet estimates that for every 1 (MBq·h)/m3 of radon exposure, the reading could increase by around 3 Bq/m3. So, for example, if the device were in an environment with 1000 Bq/m3 of radon for five years, the reading might drift upward by about 150 Bq/m3 due to this buildup. However, considering <150 Bq/m3 is considered a safe radon level, this exposure is an extreme example and won’t apply to anyone using this monitor.

With this figure in mind, this monitor should retain accuracy for a long time. So far, the highest concentrations I’ve seen on my monitor (in, admittedly, a location where radon is not of any concern) are around 50 Bq/m3, and these spikes are shortlived, and my average is around 20 Bq/m3. Obviously, many users interested in this device will have far higher levels, but even at higher levels, you should get good performance from this monitor for many years to come. With that said, the battery life might still outlast the usable lifespan of this product!

Another factor I wanted to look into was the impact of environmental conditions on the accuracy of radon monitors such as the Aranet Radon Plus. From what I’ve found online, while temperature can impact the amount of radon gas in the area, it shouldn’t impact the sensor’s accuracy (as long as it is within operating conditions). Relative humidity seems to have more of an impact, but I reached out to Aranet regarding this and was told that throughout its testing process, relative humidity had no impact on the accuracy of the sensor – again, assuming it is used within the operating conditions stated (0 – 50°C and 0 – 85% relative humidity).

Interestingly, while the tests indicated little impact by temperature and relative humidity, a slight dependency on air pressure was found, and for that reason, Aranet chose to include an air pressure sensor in this device. While you won’t notice it as the user, this sensor automatically feeds data to readings you see on the screen and in the app to ensure they are corrected through varying air pressure conditions. Importantly, the device retains its stated accuracy within the complete operating condition range.

While I will wait for more third-party tests or certifications (which I hope are coming!) to make any definite conclusions about the accuracy, it looks at least on par, if not slightly better, than the competing options in this price range. I’m very impressed by the level of transparency that Aranet has provided concerning the device’s inherent inaccuracies (which are present in all monitors) and caveats. I haven’t seen any other large manufacturers in this space provide such detail.

Before I move on, there is one more note I want to make regarding accuracy. The Aranet Radon Plus can display radon in either becquerels per cubic meter (Bq/m³) or picocuries per litre (pCi/L). I appreciate having the inclusion of both metrics as many people are likely more familiar with one than the other. Personally, as someone who wasn’t familiar with either, I’ve chosen to use Bq/m³ as it appears to be more commonly used in studies and academia.

Regarding temperature and relative humidity, it seems that Aranet has kept its usual accuracy, and this monitor performs very well. Compared to the Traceable monitor that I use as a reference, the Aranet Radon Plus was always within half a degree Celsius and within a few percentage points of humidity. As both devices have some errors, this is expected, and I was impressed with how the device performed overall. Like the Aranet4 Home, you can expect to get good temperature and relative humidity readings from this device.

Design

On one hand, the Aranet Radon Plus looks exactly like its siblings in the Aranet Home family. On the other hand, as soon as you turn the device around, you realise it is much larger and almost three times as long. While this means it’s far less portable than the other Aranet Home monitors, radon monitors generally aren’t meant to be moved frequently, and I appreciate the design consistency across the range. 

Overall, the monitor measures 71x71x77 mm, making it a relatively compact radon monitor similar to the EcoQube (but much smaller than devices like the RadonEye). The reason for this increase in size over the other Aranet Home devices (which measure 70 mm x 70 mm x 24 mm) is the means the monitor uses to measure the radon concentration. 

The Aranet Radon Plus uses an ionization chamber to record the radon concentration, and the need to house this sensor restricts how small the device can be – much in the same way that, until recently, CO2 monitors have needed to be a certain size to house the lasers required in transmissive NDIR sensors. However, while the device is much longer than other Aranet devices, I appreciate how the company has kept the face of the monitor the same as it fits perfectly next to other Aranet monitors on a shelf or desk.

With that said, let’s discuss the device’s ‘face’. On the front, you will find large branding, with a small E-ink screen located in the centre of the square. This display is identical (as far as I can tell) to other Aranet devices, and it simultaneously displays the temperature, relative humidity, radon concentration, battery life, and the units on the screen. A ‘ traffic light ‘ at the bottom of the screen represents your current concentration and risk level. 

The monitor also measures air pressure, but this is not shown on the device’s screen and can only be found in the app. While I’m not a fan of ‘hidden’ measurements, I think this is acceptable. I very rarely want to view the air pressure, as it remains consistent unless I’m travelling with the monitor. Again, a radon monitor is not a monitor you would want to travel with, unlike a CO2 monitor. 

On the right-hand side of the device is a small wheel that you can scroll to navigate through its four displays. These displays show the current concentration, 24-hour average, 7-day average, and 30-day average. Handily, the screen will not automatically revert to the default display (the current concentration), meaning you can set the device to display whichever metric is most important for you. Personally, I keep mine showing the current concentration and check the longer-term averages on the app. Again, the longer term averages are the numbers you should be focusing on.

I’ve never been a fan of control-wheel-type interaction methods in the past, but I actually don’t mind it on this device because it feels solid (there is no sideways movement when I scroll with the wheel) and is very responsive. Every time I scroll with this wheel, I know the device will respond, and I appreciate this implementation of a control method that I am otherwise not a fan of.

Unlike on other Aranet devices, where you insert the batteries in the back of the device, on the Aranet Radon Plus, you need to insert the two AA batteries from the bottom. The latch feels a bit flimsy, but since I don’t think I’ll be replacing batteries often (the battery life is up to 7 years, depending on factors such as Bluetooth usage), I don’t believe this to be a big deal.

Continuing to rotate the device, we find little of interest other than a couple of vents on the side of the device, which allow the gas to enter for measurement. There is also some regulatory information on the back of the device. 

Overall, the Aranet Radon Plus, like its siblings, is a very simple device. Across the radon monitors I’ve used so far, I find this to be a common trend, as most of these devices have a much more industrial appearance than other air quality monitors, which often emphasise design. For its purpose, I think this makes a lot of sense, and I personally prefer the Aranet design to most other monitors in this segment. 

Before I forget, this device’s build quality is good but nothing exceptional. Its case is entirely polycarbonate, and while it is solid and well-built, there is nothing to write home about here. If you’ve ever held any of the other Aranet Home devices (or even a Pro device like the Aranet4 Pro), you will know the build quality to expect here, as this device is identical except for being heavier and larger due to the chamber it houses.

Connectivity & App

One area in which Aranet products have always excelled is in connectivity and app support. If you’ve ever used any other Aranet Home product, most likely the Aranet4 Home carbon dioxide monitor, you will know exactly how great the Aranet Home app is already. If you haven’t yet had a chance to use an Aranet device, I will say upfront that the app experience here is fantastic. 

I want to place a particular emphasis on this with the Aranet Radon Plus because air quality monitors, in general, have a lot of improvements that can be done to improve their connectivity and app experience, but radon monitors tend to be a completely different ball game. In fact, while I was testing the Aranet Radon Plus, I was attempting to run comparisons to other devices, such as the EcoQube and RadonEye, and the app experience with both was abysmal. Therefore, while the Aranet app is already one of the best for air quality monitors, I think it’s best for radon monitors – at least out of the monitors I’ve used so far. 

As with other Aranet Home devices, the Aranet Radon Plus connects to your iOS or Android device via Bluetooth. While this does have some limitations (you will need to remain close to the device to sync it with your smartphone), I find connectivity to be great as long as the device is in the same room as mine. 

Upon downloading the app, you can launch it and jump right in. I recently upgraded my phone and had to re-add all of my Aranet Home monitors to the new app. I forgot how painless this whole process is as there is no need to make (or log into) an account, and you don’t even need to put the monitors in a pairing mode – simply open the app and tap ‘pair new device’ and all nearby Aranet devices will appear. This simplicity and ease of use are part of what makes this app so great. 

Once you’ve added your Aranet Radon Plus, it will appear under the app’s ‘home’ tab. If this is your only Aranet Home monitor, the device will appear in isolation. However, if you own any other monitors in the series (which currently consists of the Aranet2, Aranet4 Home, Aranet Radiation Monitor and Aranet Radon Plus), these will also appear in the same section. While I’m generally not a fan of brand ‘ecosystems’, Aranet’s digital centralisation of its Home devices creates a great user experience. 

Since a Bluetooth connection is required for data transfer, data will only sync between your monitor and smartphone when you open the app and try to view historical data. This is usually quite a quick process, and even when I have a week or more of data to sync, it takes less than 10 seconds to appear in the app. On top of this, the device appears to have a decent amount of internal storage, and when I set up the app on my new phone, it instantly imported about one month of previous data from the device. 

This internal storage is incredibly handy as it means the monitor can have great battery life without maintaining a constant Bluetooth connection. You also don’t need to worry about losing data if you forget to sync your monitor occasionally. I wish more monitors would hold such a large amount of historical data locally. 

Historical data can be viewed through graphs on the app. While the graphing functionality here is quite decent (you can toggle between day, yesterday, or week views), there is also the ability to export data for anyone wanting to graph or inspect the data using more specialised software such as Excel. Since the monitor also has a temperature, atmospheric pressure and relative humidity sensor, you can view and export this data alongside the radon readings. 

While the app is generally quite simple, there are a few other options to customise your experience. Most importantly, you can change the radon units displayed between pCi/L and Bq/m3. While these measurements both indicate the same thing (radioactivity within a volume of space), some people may be more familiar with one, and it’s nice to have a choice. You can also choose to show the current radon measurement or a daily, weekly, or monthly average. Personally, I tend to use daily or weekly averages as radon isn’t a big issue for me, and the concentrations don’t change very rapidly (if the monitor stays in one place, anyway), and these longer averages help balance the inherent variation in readings that can occur. 

On the settings page, you will also have the option to change between temperature units, enable or disable the buzzer (you can also manually adjust the thresholds for the alarm, which default at 8.1pCi/L), and enable smart home integration – but more on that soon! There is an option to update the device, too, and Aranet is normally quite active in this respect. I received an update to my device just the other morning, which improved battery life and included a few other small fixes. 

In the settings for the app (as opposed to on a per-monitor level), some extra settings allow you to toggle between pressure units, temperature units (across all monitors), date format, and even toggle background data read, which will allow you phone and Aranet devices that are in range to sync every few hours. While I love having this option, I prefer to keep it disabled to save battery life – especially as these devices appear to have decent internal storage. 

If you want to integrate your monitor more thoroughly into a smart home or use it to control automation, the Aranet Radon Plus also currently supports Home Assistant (through Bluetooth). While the Aranet4 Home also supports Homey, it seems that this integration has not yet been carried across to the other Aranet Home devices as I can add them to my Homey Pro, but they aren’t recognised and show CO2 as opposed to radon, showing the integration is clearly only targeted at the Aranet4 Home for now. 

My Home Assistant dashboard with the Aranet4 Home, Aranet Radiation, and Aranet Radon Plus data displayed.

Luckily, Home Assistant works with all Aranet monitors. By default, the monitor comes with six entities: battery life, relative humidity, air pressure, radon concentration, temperature, and update interval. Although I sometimes have questionable Bluetooth connections, I’ve found the Aranet Radon (and all Aranet Home devices) to work well with my Home Assistant setup as long as they’re within a room or two of my Raspberry Pi.       

I appreciate that SAF Tehnika allows the Aranet Home series to have integrations with these platforms instead of trying to keep everything within the Aranet app. While many integrations still aren’t supported (at least not officially), I hope we continue to see more integrations in the future. I would also love to see the Homey integration carried over to non-Aranet4 devices, but I understand the choice as I’m sure the Aranet4 is by far their most popular seller. I’ve been told Aranet will work on a Homey integration for this device, but there is no indication as to when this will be released.

Either way, if you use Home Assistant, you will find the Aranet Radon Plus an even more powerful tool with the range of integrations that it can bring. While there aren’t many automations that I can think of that you would want to run with a radon monitor (for example, you wouldn’t want to turn on an air purifier at a certain concentration like with an air quality monitor), it’s nice to have these options available. 

Overall, the Aranet Radon Plus has excellent connectivity, provided you place the monitor near your smartphone or Homey/Home Assistant host device. If you choose to use the Aranet app, you will find it fast and fluid to use with all the essential features. It’s also a vastly better app than anything else I’ve found with a radon monitor so far. Of course, if you want the extra features that Home Assistant offers, these are also available to you!

Pricing and Competition

Perhaps the biggest downside of this monitor is its price. As with all Aranet Home products, this monitor has a higher price, but it can be considered quite a premium monitor. While I will have to test more radon monitors to have a complete overview of the scene, this monitor may likely be like the Aranet4 Home, which is a pricey carbon dioxide monitor, but it’s well worth the price as it’s one of the best in its class.

The Aranet Radon Plus sells for 189 USD (although you can save a bit with the code ‘BREATHESAFEAIR’ and support my blog). This puts it in the same price range as other ‘premium’ consumer-grade radon monitors. Please remember that these monitors are very different from the professional radon monitors that sell for $600+ and hold certifications from different bodies (like NRPP). Hence, I will call these consumer-grade monitors, even if they are quite premium within this segment.

At this price, the Aranet Radon Plus is in the middle of the price range of reputable consumer-grade radon monitors. Without further accuracy reports for the device, it’s hard to know exactly where it sits and what I would recommend. That said, I think the Aranet Radon Plus is undoubtedly the monitor with the best feature set and connectivity (I have not used the Luft monitor, but I have tested all the others). It’s also an easy choice if you already have other Aranet monitors.

It’s also worth noting that unless you’re willing to change your app store, you will need to find a monitor that works in your region. This likely won’t be an issue if you’re in the U.S. or Europe. However, I couldn’t find the RadonEye and EcoQube apps on the Philippines or New Zealand app store, meaning using these devices has been a big ordeal that has frustrated me endlessly. On the other hand, the Aranet and Airthings devices appear to have app support in more regions (at least they did in my case).

It’s also important to note that out of the monitors I’ve tried, only the Aranet Radon Plus and Airthings Corentium are what I would consider usable without an app. While they are both better with the app, they display enough information on their displays to be used as standalone devices if desired. The EcoQube can’t be used without an app, and the RadonEye shows one reading, but that is all. If you want a standalone device, either the Aranet or Airthings monitor is a better choice.

Overall, the best monitor will depend on your individual use case. However, seeing another brand offering a competing product in this price range is great. At the moment, the Aranet Monitor already excels in a few areas, and it’s the most user-friendly radon monitor on this list. Once it has some more testing behind it, I look forward to coming back and updating this review!

Conclusion

Over the past month, I’ve had a lot of fun setting up and using my new radon monitors. While these types of monitors are still quite new to me, I’ve become rapidly acquainted with them after checking their readings every day and learning the ins and outs of every monitor. While I haven’t yet had time to publish full reviews of the other monitors (those are coming soon!), I have quickly found the Aranet Radon Plus to be the most user-friendly monitor in the group.

Based on official specifications alone, the device also has performance that puts it on par (or perhaps makes it better than) other reputable monitors like the EcoQube and RadonEye. While it’s hard to tell exactly where it stands, as the other brands don’t share information on their error or confidence intervals, I appreciate Aranet’s transparency in this regard. I look forward to seeing further testing on this monitor, but currently, the official specifications show it to be an accurate monitor.

When it comes to connectivity, this device shines. The Aranet Home app is already a fantastic app, but my recent discovery that the Aranet Home series of monitors support Home Assistant has made me realise just how powerful these monitors truly can be. I don’t believe many other radon monitors natively support Home Assistant, so this was a very exciting discovery for me.

That said, the device is quite pricey, and I can understand potential customers are tempted by the more established and cheaper EcoQube or Airthings Corentium Home. While I find the Aranet Radon Plus to be the best of these monitors, I believe they all offer compelling options. Perhaps the biggest downside is the device’s reliance on Bluetooth. While this isn’t a big issue as the monitor itself stores a long period of data, I wish these monitors supported WiFi so I could easily view the radon concentration in different rooms (especially if one monitor is placed in a basement, where WiFi signal is often weak) from anywhere in my home.

I hope this review has given you enough information to decide whether or not the Aranet Radon Plus is the right radon monitor for you. If you’ve read this review and still have questions, please feel free to ask below! If you’ve used this device, please feel free to share your thoughts. I would love to hear what you think of it! Thank you for reading.

Aranet Radon Plus Review - The Most Convenient Radon Monitor

The Aranet Radon Plus is a user-friendly, accurate radon monitor with long battery life, smart home integration, detailed app support, and reliable real-time tracking.

Product Brand: Aranet

Editor's Rating:
4.5

Pros

• User-friendly interface with a responsive control wheel
• Supports Home Assistant integration for smart home use
• Displays current and average radon levels on the device screen
• Up to 10-year battery life for long-term monitoring
• Detailed app support with easy data syncing Includes temperature, humidity, and pressure sensors
• Clear accuracy reporting with a ±8% margin for 95% of readings
• Compact and well-designed to fit alongside other Aranet devices

Cons

• Pricier than some other consumer-grade radon monitors
• Larger and less portable than other Aranet Home devices
• Bluetooth-only connectivity, no WiFi support
• Battery compartment latch feels slightly flimsy