Carbon Dioxide (CO2) monitors are growing popular amid COVID-19. CO2 monitors can help measure ventilation and help lower COVID spread. But what are the best and most accurate CO2 monitors on the market? To find out, Smart Air analyzed CO2 monitor test data to bring you recommendations for the best CO2 air quality monitors in 2021.
Why Use CO2 Monitors for COVID-19
CO2 monitors can help measure how well a room is ventilated. The higher CO2 levels are, the worse the ventilation. Why is ventilation so important when it comes to COVID-19? The CDC has released data showing strong correlations between poor ventilation and high COVID-19 spread.
Factors for choosing a CO2 monitor
When buying a CO2 monitor, some important factors to consider include:
- Mobility: A monitor can either be permanently installed or portable. Portable CO2 monitors are more versatile, and can be used for multiple rooms
- Sensor Time Response: A monitor needs to be responsive to changes in CO2 levels. Some monitors take a few minutes to respond, but good monitors respond in a few seconds.
- Data processing: A monitor must be able to export recorded data to a hard-drive for further analysis.
- Accurate Background Calibration: A monitor should record a value of 400 parts per million (ppm) outdoors. This indicates that it is accurately calibrated.
- Calibration Method: Monitors can allow automatic or manual calibration, or both. Automatic calibration is easier and more straightforward than manual calibration. However, manual calibration can produce results more quickly, especially when the monitor shows significant inaccuracy.
Recommended CO2 Monitor Technology
In general, CO2 monitors with non-dispersive infrared (NDIR) sensors work very well. Cheaper devices with several sensors that measure Volatile Organic Compounds and Formaldehyde alongside CO2 are not recommended. This is because they likely use a different type of sensor which is less accurate.
Best CO2 Monitors for COVID-19
Below are the best CO2 monitors that are in line with the above factors. These recommendations are based on extensive CO2 monitor tests. All monitors had accuracies at or above 94%. For full details on the monitor tests, check out the test data.
Note: R2 is used as the measure of accuracy of the monitors. R2 measures how much variance exists between the actual value of CO2 versus the calculated value by each monitor. An R2 of .7 is represented by an accuracy of 70% in this article.
Expensive relative to the competition, but the Aranet 4 is very accurate, with readings closely tracking the reference CO2 detectors used. It is recommended to do a weekly calibration of the Aranet 4 monitor. Data can also be collected with an app.
Price: $230 USD
A more expensive option, Temtop is highly accurate and with good background calibration. However, it does not contain any data export function.
Price: $180 USD
Kkmoon / Kecheer / Curconsa / Aprotii
A monitor with a mid-range price, Kkmoon monitors are highly accurate (reproducible data of up to 2000 ppm) and allow for data to be exported as a PDF file or even copied to an excel sheet for analysis. Kkmoon monitors are also robust and require a re-calibration prior to usage. Some manufacturers name the monitor k=Kecheer, Curconsa, or Aprotii.
Price: $110 USD
Wohler CDL 210
More expensive than most of the other options, the Wohler CDL 210 is one of the most accurate. Moreover, it enables continuous logging and subsequent data export to PC (even with no power). However, Wohler sacrifices some portability as it has to be plugged in during measurement.
Price: $212 USD
A more expensive option, the AZ 7755 boasts a higher accuracy than most monitors on the market. Data can be stored and analyzed on a PC with the appropriate cable.
Price: $180 USD
Almost similar to AZ 7755 in terms of price and accuracy, SA1200P has a good quality to price ratio. However, the monitor has to be plugged in during measurement and does not allow for exporting of data. That being said, SA1200P has data visualisation options and the option of background calibration, which are always useful.
CO2 Panel Pi
A mid-priced option, CO2 Panel Pi is the least accurate of the recommendations. The monitor possesses an LED that lights up according to the CO2 level, instead of a display to monitor CO2 concentration, and also needs to be permanently plugged in during measurement. That being said, the monitor is highly customizable, with programmable measurement intervals and the option of manual or automatic calibration.
Price: $150 USD
The cheapest of the CO2 monitors, DM1306 still offers the highest accuracy. However, DM1306 needs to be plugged in for measurement and is also mounted on the wall. It does not export data, and cannot be calibrated manually.
Price: $64 USD
Nearly twice the price of the DM1306, the DM1307 contains nearly all of the same features and similar accuracy. The main difference is that the DM1307 has a larger screen.
Price: $122 USD
The complete CO2 monitor test data is available for free to download.
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