INKBIRD PTH-10C – My New Favourite Affordable Carbon Dioxide Monitor

One of the most common questions I get asked is ‘What is the best affordable carbon dioxide monitor?’. In fact, I probably receive this question more than any other carbon dioxide monitor-related question, and it’s one that I often struggle to answer. Why? Because there aren’t many choices and, predictably, the choices in this price range often come with flaws and caveats.

When looking at devices in the < $50 price range, the most important consideration is always the sensor type. While some devices try to obscure their sensor technology, it’s vital to ensure the device uses an NDIR (non-dispersive infrared) or photoacoustic sensor. These are the gold standard of CO2 monitoring, and this technology powers much more expensive devices like the Aranet4 Home.

It’s essentially due to this fact alone that I’ve recommended the Vitalight Mini CO2 Detector as the best low-cost option for so long. While the device has quite a few flaws (I’ve also been hearing quite a few reports of bad durability), it has one redeeming factor – it uses an accurate NDIR sensor, which is difficult to find in a device under $50, let alone under $30.

However, I’ve recently been getting quite a few questions about trying another low-cost monitor – the INKBIRD PTH-10C. This device comes at a very similar price to the Vitalight, and it offers a few other advantages over its competitor. While both use an NDIR sensor, the PTH-10C has audible alarms with adjustable thresholds and, more importantly, allows the user to disable automatic calibration. This is fantastic, as I’ve always wanted to see it on the Vitalight.

For these reasons, I am excited to present my full review of the INKBIRD PTH-10C. I was really hoping this device would perform well, as it would be great to have another low-cost CO2 monitor recommendation. How did it hold up? Well, you’ll have to read on to find out! As always, if you have any questions or comments, please feel free to comment on the article in the comments section below. With that out of the way, let’s dive in!

This post contains affiliate links. For more information, please refer to my affiliate disclaimer. I was NOT sent a product for review; I purchased this monitor myself. All opinions expressed in this post are my honest thoughts. I only recommend products that I 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, which is subject to change without notice. Devices mentioned on this website are not medical devices and do not guarantee protection.

Accuracy & Sensor

The biggest issue with monitors in the budget price range is that it’s often hard to tell exactly what type of sensor they use. While this might not seem too important initially, sensor type is a crucial consideration when deciding which carbon dioxide monitor to purchase. The key here is to look for a device with an NDIR sensor (photoacoustic sensors are also good), as these measure only carbon dioxide and tend to do so very accurately.

On the other hand, if you get a device with a different sensor type, like an MOS (metal oxide semiconductor) sensor, you will only see eCO2 levels – equivalent carbon dioxide levels. In other words, the device isn’t measuring carbon dioxide, but rather measuring VOC levels and estimating carbon dioxide concentrations. This is far from helpful, as this means that if the sensor detects a VOC, it will indicate an increase in carbon dioxide levels even though this is probably not the case.

Therefore, your first step when assessing if a carbon dioxide monitor is accurate is to check the sensor type. While I’m sure there are bad NDIR sensors out there, I have yet to encounter one that gives unusable readings. Luckily, INKBIRD advertises an NDIR sensor inside the PTH-10C, and from my testing, this looks to be the case as the readings track quite closely with my other monitors, such as the Aranet4 Home.

Unfortunately, despite opening the monitor up, I have been unable to find out exactly what NDIR sensor is used in this device, as it isn’t labelled. While I expect it to be a cheap sensor, considering the price of the device, it looks to perform relatively well, and it’s good to know that even in this price range, it’s now possible to get carbon dioxide monitors with decent sensors.

At the moment, the only other device in this price range with an NDIR sensor (that I’ve tested – I don’t want to recommend anything I haven’t tried myself) is the Vitalight Mini CO2 Detector. While that’s a surprisingly accurate device given the price, it also has quite a few drawbacks in other areas outside of accuracy. As such, I’m excited to see if the PTH-10C can provide similar accuracy with better features – but that’s getting ahead of myself. Let’s first see how the readings from the PTH-10C compare to a more expensive and accurate device.

Since it’s quite painful to compare the PTH-10C to other devices (it’s a very manual process due to the lack of the ability to export data), I decided to compare the recorded concentrations of carbon dioxide over two hours to the Aranet4 Home – a carbon dioxide monitor that is often considered the gold standard of consumer-level accuracy. While I would have loved to have carried this comparison out over a longer period, manually viewing the monitor for two hours was already painful enough!

As you can see, both monitors recorded very similar readings, with the PTH-10C generally having slightly more varied readings and consistently reading a bit higher. While both devices were calibrated under the same conditions and simultaneously, this consistent difference is likely due to differences in the baseline calibration of both devices. Luckily, besides having more variation in its readings, the PTH-10C provided similar readings to the Aranet4 Home. It also clearly showed the same overall trends.

While it’s anecdotal, I carried both the AirSpot CO2 monitor and PTH-10C for around one week, and I regularly checked both devices. While sometimes there would be variations of ± 100ppm between the devices (the different reading intervals likely caused this), both closely tracked each other. There was never a case when I questioned why the devices had such different readings. Based on this, I’ve come to trust the readings from the INKBIRD PTH-10C.

Over time, even the best NDIR sensors drift, leading to readings from the device becoming inaccurate. Thankfully, all decent carbon dioxide monitors include the ability to calibrate the device – this includes the INKBIRD PTH-10C. While most devices also feature automatic and manual calibration, some only feature one or the other, including the comparable Vitalight Mini CO2 Detector. For a full explanation, please read the information box below. The non-disableable automatic calibration ‘feature’ of the Vitalight is one of its biggest downfalls.

On the other hand, the PTH-10C features both the ability to manually calibrate the device, and it even allows the user to enable or disable automatic calibration – a feature that I wish were present in every carbon dioxide monitor. This might seem like a basic feature, but I am happy to see it here. Unfortunately, I haven’t been able to find out how regularly the ABC operation is carried out, but I assume it’s on a 7-day cycle like most carbon dioxide sensors.

Overall, from my testing and my experience using the PTH-10C, I trust the readings that come from this device. As per the specifications sheet, it has an accuracy rating of ± (50 ppm + 5%), and I believe this to be true. This is also a similar accuracy rating to what you will find on many far more expensive monitors, making it all the more impressive. However, as with all carbon dioxide monitors, you will want to remain on top of calibration (or, more importantly, automatic calibration) to ensure the best accuracy.

One final note for this section: despite the PTH-10C manual mentioning that the device has a temperature and humidity sensor, it doesn’t seem to be possible to actually get data from this. As such, I couldn’t test this sensor’s accuracy, and I’m unsure what it’s used for. It could be assisting with enhancing the accuracy of the readings from the NDIR sensor, but it’s hard to tell with no other mention of this sensor anywhere in the documentation.

Design

The PTH-10C is a relatively small, round device coming in at 76mm × 70mm × 30mm (2.99 in × 2.75 in × 1.18 in). It’s also relatively heavy, and I believe this is mostly due to the heavy (but durable-feeling) plastic and internal battery. Regardless of the reason, for a low-cost device, this feels quite solid, and that gives me the impression that at least the casing is durable. While I can’t speak for the long-term durability of the device yet, I’ve been using it for around one month, and I haven’t been babying it (it goes in my backpack along with everything else when we travel), and it’s held up well so far – but that’s expected.

What I can say, however, is that it certainly feels more durable than the similarly priced Vitalight Mini CO2 Detector, which I have been drawing many comparisons to throughout this article. I also know for a fact that that device has durability issues for many users, and I’m hoping that this won’t suffer from the same issues. While I will have to update this article in the future with my findings, I have hope for this device!

On the front of the device is a bright, visible screen with nice colours and viewing angles. The device also comes with a screen protector preinstalled, which is a minor but nice touch. Above the screen is a hole for a lanyard or carabiner, and below the screen is the only button on the device. This button has a few functions that we will discuss in more detail soon.

Turning the device around, we find venting around the edges of the device, which allows for ambient air to enter the device for measuring. There are also three screws located around the edges of the device that allow you to open it easily. While I don’t know why you would want to do this (unless you’re me!), It’s nice to have easily accessible internals. At the bottom of the back is a USB Type-C port that will allow you to charge the device. Importantly, this port will not allow you to export data.

With the basics out of the way, let’s move back to the front of the device. Here, you will find a screen which is surprisingly nice for such a low-cost device. The screen will show the current CO2 concentration (in parts per million), and below this, you will find a few status icons indicating the buzzer (alarm) and battery status. Around the edges of the display, you will find three bars – a green, yellow and red bar that indicate the current CO2 concentration.

All of these bars will be visible at all times, but one of them will flash depending on the current CO2 concentration. For example, if the concentration is good, the green bar will flash. The thresholds for each of these bars to flash are as follows:

• Green: 400 – 699 ppm
• Yellow: 700 – 1499 ppm
• Red: 1500+ ppm (adjustable)

Interestingly, while the green and yellow thresholds are not adjustable, the red threshold is. It’s also important to note that the alarm is tied to the red threshold, so you can adjust both the concentration at which the alarm buzzes and when the red bar flashes. I really like this touch, and many monitors in this price range don’t have such a feature. With that said, the alarm is quite annoying, so I tend to turn it off myself.

As for the function button, you can find it below the screen; this will be your main (and really, only) way to control the device. Holding this button down will let you turn the device on or off, and short presses will allow you to perform other actions such as enabling the alarm, automatic calibration, and also performing a manual calibration and changing the alarm threshold. While the manual is a bit hard to follow, once you get used to it, interacting with this device is quite easy.

All in all, the design of this device isn’t exceptional, but it is very solid, especially considering the price. There’s not much more I could ask for in such an affordable device, and I think the design is better than most other devices in this price range.

Battery Life & Connectivity

The INKBIRD PTH-10C has no connectivity options, meaning that outside of using the device itself, there is no way to interact with it. While I might normally complain about this, I think this is reasonable at this price point. Unfortunately, this means that some features will be missing – think viewing historical data, remotely triggering calibrations, and so on – but it also means that this device works best as a standalone monitor that doesn’t need to be tethered to a phone to work.

Since there is no connectivity, battery life is quite good, and the 1000mAh lithium polymer battery provides up to 72 hours of battery life. While this may be shorter depending on your usage, you’re basically guaranteed to get at least two days of battery life out of the PTH-10C. Considering that many other devices in this price range last for 1-24 hours, I am very happy to see such good battery life on this monitor.

To keep the battery life decent, the device will put itself to sleep if it hasn’t been used for five minutes. While this is fine and makes sense, it does take a couple of minutes after turning the device on again for it to accurately record the CO2 concentration. In other words, you can’t pull it out of your pocket, power it on, and get a reading immediately. Instead, you will need to wait a minute or two for representative numbers to begin appearing.

While I haven’t been able to find any mention of how often the device takes a reading from its NDIR sensor, I would guess it is taking a reading every 1-3 minutes while powered on. It’s worth noting that the screen will update much more rapidly than this, but I believe this device performs similarly to the Vitalight, which takes an actual reading every few minutes but shows updates every few seconds. It’s important to note, however, that these frequent ‘readings’ are only showing trends based on the previous (actual) measurements.

Although I would like a bit more transparency here, I think the balance between battery life and measurement frequency is acceptable for most users. On top of that, I appreciate that the device includes Type-C fast charging, meaning that charging the device is a breeze.

Pricing

The INKBIRD PTH-10C is a very affordable carbon dioxide monitor that costs under $40, and sometimes under $30 if you can find it on sale or discounted. It is also possible to find the device cheaper on websites like AliExpress, but I expect most people will purchase this device through Amazon or another local e-commerce site. I purchased mine from Lazada Vietnam, and it cost $33.

In this price range, there really isn’t much competition. While there are likely some other low-cost NDIR-based carbon dioxide monitors out there, I haven’t yet had the chance to test them. Therefore, I don’t want to comment on these potential alternatives as I really can’t speak on their strengths and weaknesses (and whether they have a legitimate NDIR sensor). I also believe there are probably some other decent, low-cost options on websites like AliExpress, but it’s hard to say without testing the devices myself.

As such, I see the main competition to this device as being the Vitalight Mini CO2 Detector – a monitor that is slightly cheaper, and that I’ve used for a few years. However, despite being slightly cheaper, I think the PTH-10C may well be a better buy due to the better build quality and a couple of additional features – for example, the ability to disable automatic calibration, which I’ve always wanted on the Vitalight.

At times, the price difference between these two devices can be around $10, which is quite significant when that accounts for 25-35% of the device’s overall value. However, I do think that I would now recommend spending that bit extra to get this monitor instead of the Vitalight, as the benefits this device brings warrant spending a bit more, at least in my mind. While it will really come down to what you value, I believe both devices should at least be considered.

Therefore, I think the INKBIRD PTH-10C pricing is quite reasonable, and I’m thrilled to see another carbon dioxide monitor that I can recommend in this price range. While you can find it on sale at times (and it’s often cheaper in some regions than others), I think even at full price, this device offers a compelling feature set.

Conclusion

Going into this review, I wasn’t too sure what to expect. While I’ve reviewed some INKBIRD devices that I really liked (see my review on the IAM-T1), I’ve also reviewed INKBIRD devices that I thought were pretty bad (see my review on the PTH-9A). This led me to be quite uncertain about this device, as I know that INKBIRD can make some great devices, but they can also make devices that I simply can’t recommend. Luckily, the PTH-10C seems to be one of INKBIRD’s better products.

Admittedly, this is a simple device. It doesn’t have any connectivity, and you can’t see any historical data on it. Beyond that, you can’t even see temperature and relative humidity data (despite the device seemingly having the sensors to show this). However, at the price point, these features can’t be expected, and the PTH-10C is quite a compelling option for anyone needing only simple carbon dioxide insights.

While the device, as expected, doesn’t have the same feature set as more premium models, it covers the basic functionalities very well, and it offers enough over other affordable carbon dioxide monitors to justify the slight price increase (I am primarily comparing it to the Vitalight when I make this statement). Based on the durability complaints I’ve heard about the Vitalight device, I have already begun to recommend this as my go-to low-cost carbon dioxide monitor.

That about concludes this review. If you’re looking for a low-cost carbon dioxide monitor and don’t need the extra features of more expensive monitors, I believe the PTH-10C is a device that you should consider. It’s solid, and it does its job well. Most importantly, it’s accurate and has great battery life.

Have you tried the PTH-10C? If so, please let me know your thoughts in the comments below. It would be great to hear how others have found this monitor! Alternatively, if you’ve read this review and still have some questions, please don’t hesitate to let me know in the comments form. I’m happy to help, and I do my best to answer all questions I get! Thank you for reading.

INKBIRD PTH-10C FAQ

INKBIRD PTH-10C - My New Favourite Affordable Carbon Dioxide Monitor

A detailed review of the INKBIRD PTH-10C, a budget CO2 monitor with an NDIR sensor, manual calibration, and solid features under $40.

Editor's Rating:
4

Pros

• Uses a true NDIR sensor for accurate CO₂ readings
• Affordable – often available for under $40
• Allows disabling of automatic calibration (a rare feature in this range)
• Durable-feeling build with a preinstalled screen protector
• Decent battery life (up to 72 hours) with USB-C charging
• Adjustable alarm threshold with visual CO₂ level indicators

Cons

• No app, Bluetooth, or Wi-Fi connectivity options
• No ability to export or view historical data
• Temperature and humidity sensors are inaccessible to the user
• Slow wake-up time after being powered off or asleep
• No customisation options (such as changing the reading frequency)