We researched more than 50 of the best CO2 and air quality meters available today before buying the 9 best for hands-on testing. We compared the readings of each model to professional grade CO2 and air quality meters in multiple different settings to verify their accuracy. We also used each meter for multiple weeks to see how easily they could keep track of long-term air quality trends. Whether you're looking to monitor the CO2 levels in your home to make sure you have proper ventilation, or want a way to verify that your new air purifier is actually making a difference, we can help you find a great air quality meter.Indoor comfort starts with air quality. That's why our expert reviews cover everything from humidifiers, air purifiers, and portable air conditioners to smart thermostats and space heaters to help you find the right appliances to control the comfort level of your home.
Our Top Picks
For those who want to track common air pollutants and CO2, we think the Awair Element Indoor is one of the most useful devices on the market. Within its associated app, you can easily track both the current air quality in your home as well as its long-term trends. You can also enable notifications for when individual air pollutants reach critical levels. The WiFi connection allows you to access these measurements from anywhere with an internet connection, so you can check in and make sure your heater hasn't broken while on vacation. You can also choose to display the measurement of your choice on the front of the meter, allowing you to get an update at a glance. To top it all off, this meter easily passed our baseline accuracy tests for both PM2.5 particulate matter and CO2.
Our main complaint about this model is that it only operates when plugged in, limiting placement in your home. Additionally, the LED display can be somewhat challenging to read, especially in brightly lit settings. Despite these minor gripes, we think the Awair Element Indoor Monitor is a valuable tool for tracking air quality in any home.
When it comes to monitoring the air quality of your home, long-term trends and averages are often more telling than individual measurements. This is where the Airthings 2930 Wave Plus, one of our favorite air quality meters, shines. Its user-friendly app allows you to quickly scroll through 48 hour, weekly, monthly, and yearly averages, as well as trend graphs, for all of the contaminants it measures. It is also one of the few consumer meters on the market that measures radon, making it a good choice for those in high-radon areas. If you don't want to constantly check your phone, you can set notifications for when individual contaminants reach critical thresholds. Alternatively, you can just wave your hand over the meter to get a simple green, yellow, or red summary of the overall air quality. This meter can run for many weeks on 2 AA batteries, meaning you can place it anywhere you'd like regardless of outlet access. Finally, it passed our basic accuracy test for CO2 monitoring.
The biggest strike against this air quality meter is the lack of PM2.5 tracking, meaning it doesn't track the particulate air pollution associated with wildfires and other smoke. Additionally, the meter only communicates with your phone via Bluetooth, so you must be within 30 feet or so to download new data. While not a dealbreaker, on such a capable meter we would have appreciated a WiFi connection that allows for monitoring when on vacation (a WiFi hub is reportedly in the works). Overall, if radon monitoring is of concern to you and you don't mind the lack of particulate pollution tracking, there isn't much to complain about with the AirThings 2930 Wave Plus.
The Yvelines Air Quality Tester provides reliable air quality monitoring at a significantly lower cost than many of the most popular models. It covers all the bases, offering two different particulate pollution measurements, as well as volatile organic compounds, formaldehyde, and CO2 measurements. We were particularly impressed with its PM2.5 (the pollutants associated with wildfire smoke and other smoke-based sources of air pollution) accuracy, as throughout our tests it stayed almost in lockstep with our professional-grade air quality meter. Simple controls let you scroll through recent short-term averages for each measurement. These averages change based on the measurement; for example, the formaldehyde average is 60 minutes, while the CO2 and PM2.5 averages are 10 minutes. The color screen is easy to read regardless of lighting conditions. The built-in battery allows you to take measurements without power for up to 12 hours at a time.
While we find the short-term averages provided by the Yvelines Air Quality Tester to be quite useful, they likely won't be sufficient for those interested in tracking long-term air quality trends in their home. Doing so would require labor-intensive manual tracking of the unit's readings. Additionally, this unit's CO2 readings were consistently more than 10% off from those of our professionally calibrated CO2 meter. However, its CO2 readings were consistently 15% to 20% higher than expected. Since it typically read higher than the calibrated pro meter in our testing, we still feel it could be a useful tool for those wanting to make sure the CO2 concentration in their home doesn't get too high. Overall, this meter is a great and relatively inexpensive option for those that want to make sure the air quality in their home stays within acceptable limits during wildfire season or the cold winter months when proper ventilation becomes difficult.
If you travel a lot and want to spot-check the air quality in your hotel room, the Huma-i Advanced HI-150 is a great tool. This tiny monitor can easily fit in a front pocket and quickly boots up to provide a wide array of air quality measurements. The LCD screen is easy to read, and simple green, yellow, and red indicator lights provide a quick reference for the current air quality. The single button allows you to scroll through each of the provided measurements.
Since this device is geared towards travel and periodic use, it doesn't provide any of the long or short-term trends and averages one might be interested in when using an air quality meter in their home. Additionally, it doesn't provide an actual CO2 concentration, just a good, moderate, or poor readout along with a small bar chart. Still, based on our comparisons between this and professional-grade air quality and CO2 meters, we think it can provide valuable peace of mind when traveling to areas where air quality may be an issue.
CO2 concentration can be a good indication of the ventilation in your home. More specifically, it can help you ascertain whether exhaled air is building up in your home, or being properly ventilated. Therefore, in certain circumstances, keeping indoor CO2 levels low can help mitigate the risk of airborne virus transmission. If this is your main purpose for monitoring indoor air quality, we highly recommend the Gain Express Wall Mount. First off, the readings on this meter stayed incredibly close to those we saw on our professionally calibrated CO2 meter throughout our testing, giving us a high degree of confidence in its accuracy. Secondly, the convenient wall mount and large display allow it to be placed in an easily readable position. This negates the need to repeatedly check an app on your phone or constantly saunter over to the meter to keep an eye on CO2 levels. Thirdly, if you need help remembering to monitor CO2 levels at critical times, you can set custom alarms that will sound when the concentration reaches a particular level. Finally, if you're more interested in CO2 concentration trends and averages, this unit can quickly display averages for both the last 15 minutes and the last 8 hours. If you want to go further, the unit can be connected to a PC via an RS232 connection for continuous data logging.
A slight knock against the Gain Express Wall Mount is its lack of a battery, which makes it harder to move it around the house as needed. Additionally, it is CO2-focused, so it won't be helpful during the summer fire season. However, if you're concerned explicitly with CO2, this meter offers reliable and straightforward tracking with a display that can be read from a distance.
For folks mainly interested in keeping an eye on CO2 levels, the Forensics Basic CO2 Meter offers simple, straightforward, and accurate monitoring. In our testing, it consistently read very close to our professionally calibrated CO2 meter, providing us with confidence in its accuracy. This meter is powered via a micro USB cable and has an internal battery that can last up to 12 hours. The clear digital display conveys the current CO2 level, temperature, and humidity. You can also set low and high alarms to warn when the CO2 level moves above or below a user-defined threshold.
This meter's biggest weakness is its specificity — it only measures CO2. Additionally, it lacks the ability to easily provide any longer term trends or averages for its measurements. If your main concern is knowing when the CO2 concentration moves past a certain limit, we think the Forensics Basic CO2 Meter is one of the simplest and most effective devices on the market.
We were impressed with the accuracy of the Temtop M2000C during testing. It consistently returned measurements that were very close to those of our professional-grade air quality and CO2 monitors. You can access short-term graphs of each pollutant it measures going back as far as the unit has been turned on. You can also set custom alarms for each of those pollutants, providing an audible signal if they reach critical levels. The entire unit is powered via a rechargeable battery, allowing you to use the unit away from an outlet. All of these features make the Temtop M2000C perfect for monitoring air quality when working on a project that could produce airborne pollutants.
The Temtop M2000C works great for short-term use, though it isn't the best for long-term monitoring. Using it for multiple days would require leaving it plugged in, but the charging port is annoyingly placed right next to the air sensor, making it hard to position correctly. The unit itself is shaped for handheld use — there is no easy way to place it somewhere in an easily readable position. However, for short-term air quality monitoring, the Temtop M2000C is an excellent choice.
If you're only interested in tracking the CO2 levels in your home and would like some idea of how those levels change over the course of a day, the Hydrofarm APCEM2 Autopilot offers a simple solution. In our tests, its CO2 measurements closely matched those of our professionally calibrated meter, and you can view a simple graph of those measurements for anything from the last hour to the last week. You can also set an audible alarm to warn you when the CO2 concentration reaches a certain level.
Though this device can provide a basic representation of the CO2 concentration over the last week, there's no easy way to save or export that data. Therefore, if you're one that likes to keep track of longer term trends, this may not be the meter for you. Additionally, this is one of the few meters that must be constantly plugged in. While most meters must be plugged in if you want to monitor for multiple days, the inability to temporarily place this device away from an outlet or continue to monitor in the event of a power outage is a slight disappointment. Overall, if basic CO2 trend tracking is all you need, this device fits the bill.
The HEI LIANG AIR Accurate Tester is a very simple meter that can monitor most of the common household air quality contaminants. It does this for far less than many of the competing models on the market. It also has an internal battery that allows it to be used without an outlet for up to four hours. This is one of the few air quality meters we've come across that measures carbon monoxide, but the lack of alarms means it cannot replace a traditional carbon monoxide detector.
This meter is one of the simplest models we've tested, with nary a bell nor whistle to be found. It provides instantaneous measurements with no easy way to see averages or trends. More critical are the apparent inaccuracies we observed in our testing. For example, the AQI measurement seemed to be accurate at low particulate concentrations, but blowing out candles next to the meter didn't change the AQI reading at all, while the reading on our professional-grade air quality meter skyrocketed. The CO2 reading also differed from that of our professionally calibrated CO2 meter. However, the CO2 reading was consistently 15-20% higher than the reading on our pro meter, so we feel this device could potentially be helpful in providing a warning of rising CO2 levels. We aren't big fans of this product, but it could be a viable option for those who only want a simple device that can give an indication of CO2 concentration.
Why You Should Trust Us
Author Max Mutter has been testing and writing about air purifiers and humidifiers over the last four years. During that time, he has used multiple professional-grade air quality and humidity meters and spent days carefully filling rooms with smoke and then tracking the resulting air quality as air purifiers do their work. As such, he is quite familiar with the ins and outs of using an air quality meter.
To assess the accuracy of every one of these products, we used a professional-grade air quality meter as well as a professional-grade and professionally calibrated CO2 meter. We made sure each one of our meters read close to the professional meters in both low and high CO2 and air pollution environments. We also used each meter to track the air quality in our own homes for multiple weeks. During that time, we noted how easy each one is to use, whether or not you can track long-term trends, and if you can access average measurements for specific time periods.
Analysis and Test Results
We found that most consumer air quality meters provide similar measurements to professional-grade meters, with some notable exceptions. Therefore, after verifying that each meter displayed a baseline level of accuracy, we focused the remainder of our testing on how easy each meter is to use and the kind of data each provides.
Ease of Use
The ideal air quality meter should be easy to set up and should provide quick access to current air quality readings as well as longer-term trends and averages (for many air pollutants, trends can be more illuminating than isolated readings). We tested the ease of use of our meters by installing them in our own homes and then using them for multiple weeks to track air quality trends.
If you have any interest in keeping track of longer-term trends and averages of the air quality in your home, the Airthings 2930 Wave Plus and the Awair Element Indoor are both excellent options. Both models communicate with associated apps that display daily and weekly graphs and averages for all of the airborne contaminants they measure (the Airthings adds 48-hour and yearly graphs and averages as well). These capabilities require you to download and sync applications, something the simpler models don't need. However, we found linking both of these models to their associated apps to be quick and easy — we had each device running and sending measurements to our phones within a few minutes of opening the box.
The major difference between the Airthings 2930 Wave Plus and the Awair Element Indoor is that the Airthings can run for weeks off of two AA batteries, while the Awair must be plugged into an outlet. We really appreciate the extra flexibility provided by the Airthings' battery, as it allows for easy placement on a shelf or above a cabinet even if there isn't an outlet nearby.
Outside of the app-based monitors, most of these devices are incredibly easy to set up — just plug them in and turn them on. Most also have an internal battery that allows for short-term wireless use, but generally they must be plugged in if you want to monitor air quality for multiple days.
Tracking trends and averages on these simpler models tends to be more difficult. Some, like the Yvelines Air Quality Tester, let you scroll through short term averages of air quality measurements. However, in the case of the Yvelines, none of those averages extend beyond the 60-minute mark and thus aren't useful for tracking long-term trends — unless you're meticulous enough to keep a manual log. Others, like the Temtop M2000C, can show you a basic graph and an average for as long as the device has been powered on, but it doesn't provide an easy way to look at finer scale statistics. Others still, like the Hydrofarm APCEM2 Autopilot, can provide simple graphs for the last hour, week, or year. Bottom line, some of these simpler models can provide basic trends and averages, but if you want a reliable and easy way to view and store this kind of data, we think you'll be much happier with a model that uses an app.
Particulate Matter Air Quality Accuracy
To test particulate matter air quality measurement accuracy, we used a professional grade air quality meter. Since even the best meters tend to only be accurate to within +/- 5%, we conducted a fairly simple pass/fail test. As long as our meters read with 10% of the pro meter, we declared it a pass. We took measurements in a side-by-side manner, with all meters sitting on the same table. We took measurements under normal conditions and then burned incense to make our testing room smokey and simulate a poor air quality situation. For this test, we focused on PM2.5 particulate air pollution, the prevalent pollution associated with wildfires, and smoke in general. We'd like to note that our professional air quality meter measures the number of particles in the air, while most of the meters we tested measures the mass of particles in the air. We both used widely available conversion equations to make those readings directly comparable, and made sure the raw readings responded to changing air quality in similar degrees.
Some of the meters we tested, namely the Temtop M2000C and the Yvelines Air Quality Tester, stayed in total lockstep with our professional meter throughout our testing. Most, however, tended to read somewhat lower than our pro meter when the air quality was good, but closely matched the pro meter once we introduced smoke into the environment to make the air quality poor. Based on our test results, we would still trust these latter models as they appear to be quite accurate at times when air quality may be of concern. The Awair Element Indoor and the Huma-i Advanced HI-150 fell into this category.
The HEI LIANG AIR Accurate Tester was the one meter we tested that measures particulate matter concentration that appears to be inaccurate — its AQI measurement did not change at all even when it was placed in a very smoky environment.
The rest of the models we tested, like the Airthings 2930 Wave Plus and the Hydrofarm APCEM2 Autopilot do not measure airborne particulate matter, and therefore can't be used to measure pollution from things like wildfire smoke.
Our CO2 accuracy tests closely mimicked our air quality accuracy tests. We put all of our meters on the same table next to a professionally calibrated CO2 meter. We repeated this test multiple times, comparing the reading of the professional-grade meter to those of the meters we were testing. If those meters consistently read within 10% of the professional meter's reading, we called it a pass. CO2 is a good proxy measurement for how well ventilated your home is. Specifically, it can let you know how much fresh air is coming into your home to replace all of the air that is exhaled by you, your family, and visitors, and whether you need to open some windows or ramp up your HVAC system to improve ventilation. Less CO2 in the air generally indicates there is less of a chance that airborne pathogens will be passed between individuals.Unfortunately, there are no guarantees this strategy will work well in mitigating transmission risk for new and quickly evolving airborne pathogens. However, there are medical facilities that use CO2 meters to ensure ventilation systems are working adequately, and there are successful examples where that strategysignifigantly reduced the transmission of pathogens like tuberculosis.
Most of the meters we tested easily passed this test, including the YVELINES Air Quality Monitor, the Airthings 2930 Wave Plus, the Awair Element Indoor, the Gain Express Wall Mount, and the Forensics Basic CO2 Meter.
A few monitors did not pass this test, consistently reading 15-20% higher than our pro meter. While we have some doubts about the specific accuracy of these meters, they at least seem to be consistent. Since they also consistently read higher levels of CO2 than our pro meter, we still feel they could be a useful tool for people that want a warning when CO2 levels start to rise. The Yvelines Air Quality Tester and the HEI LIANG AIR Accurate Tester fell into this bucket.
Whether you want to make sure the air in your house remains healthy during the next wildfire season, or you'd like to track CO2 levels to see how well ventilated your home is, a good air quality meter can provide valuable peace of mind. We hope that our testing results have helped you find the perfect meter for your needs and budget.
— Max Mutter
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