Best CO2 Sensors 2021 – Buyers’ Guide & Reviews

The increase of carbon dioxide (CO2) in the atmosphere has become a major cause for concern in most countries. The annual rate of increase in CO2 in the atmosphere over the last 60 years is almost 100 times faster compared to prior natural increases. This article will show you a list of the best CO2 sensors 2021 edition.

The brunt of increased CO2 is most prominent in urban areas due to continued industrialization. But urbanization has also resulted in increased CO2 levels inside homes due to lack of ventilation, resulting in major health concerns.

Best CO2 Sensors

As a result, CO2 sensors have become extremely popular in recent times as they effectively detect and provide an alert whenever the CO2 levels become higher than a particular threshold. These sensors are also used in commercial settings or in greenhouses.

Today, we have compiled reviews of the best CO2 sensors available in 2021. In this article, you will find:

  • Reviews of the five best CO2 sensors.
  • A detailed buyer’s guide.
  • Answers to FAQs.
  • Hopefully, your new CO2 sensor.

🏆 Best All-Rounder CO2 sensor
Hydrofarm APCEM2

Hydrofarm APCEM2
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🎖️ Editor’s Choice CO2 sensor
GZAIR Model 2

GZAIR Model2
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💰 Budget CO2
sensor
CURCONSA 3-in-1

Curconsa 3-in-1
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Five Best CO2 sensors in 2021

1. Hydrofarm APCEM2 Autopilot Desktop CO2 Monitor – Best All Rounder

Hydrofarm APCEM2 Autopilot Desktop CO2 Monitor & Data Logger, Data, White/Blue

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The Hydrofarm APCEM2 CO2 Monitor is an effective CO2 sensor that not only alerts you when the CO2 level is high or low but also keeps a log of CO2 levels for up to a week.

Specifications:

  • Dimension (L x W x H): 4.7 x 3.6 x 1.1 inches
  • Weight: 14.4 ounces
  • Color: White/Blue

Details: 

Multiple Functions: This Autopilot APCEM2 CO2 Monitor primarily monitors carbon dioxide, but along with that, it keeps track of the relative humidity and temperature of your room and displays it on an LED screen.

Data Log: This CO2 monitor features a memory chart that records and shows the stats & data of the last 24-hours or week (the time frame is adjustable). The trend chart displays the timeframes of a minute, hour, day, and week.

Sensor/Alarm: This CO2 monitor has a low drift 2-channel NDIR gas sensor combined with an audible alarm for high and low CO2 levels.

Optimized For Greenhouse: This sensor features a built-in directory of many common plants with their standard CO2 requirements. There are two slots for custom plant inputs as well.

Maintaining Temperature: This CO2 sensor operates in temperatures ranging from 32 to 122 degrees and relative humidity levels ranging from 0 to 95 percent.

Functionality: You can hang this CO2 monitor anywhere you want as it supports multiple hanging options with a hook-and-loop fastener in the back. This CO2 sensor is compatible with most regular smartphone chargers.

Note: The default mode in this sensor is Plant mode, so if you’re using this device for your home, then you will need to set the mode to Human where the CO2 threshold is 1,500 ppm.

Pros: 

  • This sensor works for multiple places ranging from homes, commercial use, or greenhouses.
  • Along with CO2, this sensor also keeps track of relative humidity and temperature.
  • This CO2 monitor works as a logger too and keeps track of the CO2 levels for up to a week.
  • It has a built-in directory of common plants with their standard CO2 requirements.

Cons:

  • Some users have found customer service to be unsatisfactory.

Bottom Line: 

The Hydrofarm CO2 Monitor is a great product for multiple settings, including your home, store, or greenhouse, and keeps track of relative humidity and temperature.

2. GZAIR Model 2 Indoor CO2 Meter – Editors’ Choice

GZAIR Model 2 Indoor CO2 Meter, Temperature and Relative Humidity Carbon Dioxide Detector, Air Quality Monitor, NDIR Channel Sensor, Data Logger, 0~9999ppm Range

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The GZAIR Model 2 Indoor CO2 Meter is extremely easy to use with a touchscreen TFT screen. It keeps a log of the data as well and comes with a customizable PIN to protect your device.

Specifications:

  • Dimensions: 4.7 x 3.6 x 1.1 inches
  • Weight: 14.4 ounces
  • Color: White/Black
  • CO2 Measuring Range: 0 – 9,999 ppm

Details: 

NDIR Sensor: This CO2 monitor has a dual-channel NDIR sensor that gives the highest accuracy with a fast measurement response.

Multiple Functions: What’s great about this product is that along with CO2 monitoring, you also get a temperature and relative humidity detector.

Digital Memory:  The CO2 monitor has the capacity to keep records of up to seven days of CO2 readings. You can change the different intervals at which the device tracks CO2 to get a perfect log report according to your need. 

Export Data: You can easily export the data of CO2 to a .txt file and conveniently save it on your computer.

Touch Screen: The CO2 meter features a large, 3.5-inch colorful TFT touch screen that shows all the information you need with a compact and neat appearance.

PIN Code Access: This CO2 meter comes with a customizable screen lock that helps your device to stay secure.

Customizable Options: You can customize multiple features of the touch screen, which include color, brightness, language, etc.

Pros: 

  • This CO2 meter has a very easy-to-use touchscreen.
  • Along with CO2, you also get data about temperature and relative humidity.
  • This device has PIN code access for better security.
  • It logs the data of up to seven days and lets you customize the tracking intervals.

Cons:

  • It does not have an audible alarm.

Bottom Line: 

This is an extremely easy-to-use CO2 monitor with a touchscreen, and it features PIN code access as well, a unique feature in this category.

3. Langkou CO2 Detector – Budget Choice

Air Quality Monitor Indoor,CO2 Detector, 6-in-1 Air Pollution Carbon Dioxide Detector with pm2.5/1/10, Temperature, Humidity Professional Sensor Real Time Reading, co2 Alarm Meter

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The Langkou CO2 Detector has a 6-in-1 CO2 sensor that detects PM 2.5, PM 1.0, and PM10 particles along with relative humidity and real-time temperature. It also has an alarm.

Specifications:

  • Dimension (Inches): 3.54 x 3.54 x 1.96 
  • Weight: 7 Ounces
  • Color: White/Black

Details:

Advanced CO2 Monitoring: This CO2 monitor comes with advanced infrared (NDIR) and also detects laser scattering with sensors. It is designed to track CO2 accurately, including PM 2.5, PM 1.0, and PM10 particles, temperature, and relative humidity. 

Long Battery Life: The CO2 sensor has a 2,000 mAh battery. It provides a standby time of more than ten hours when fully charged. Along with that, the real-time power through the USB charging cable allows the sensor to monitor CO2 levels uninterrupted for extended periods. 

Auto Alarm: The sensor issues an alarm whenever the CO2 level crosses the 1,000 ppm mark. The alarm makes a subtle buzzing sound. You can turn on/off the alarm by pressing the main function button twice quickly.

2.8-Inch Display: This CO2 detector has a sampling time of 1.5 seconds and displays the current air quality reading on a large 2.8-inch screen in real-time. The readings of PM 2.5, PM1.0 and PM10 automatically switch every five seconds.

Easy to Carry: You can set this CO2 sensor anywhere you want in your home, school, shops, campground, or office to keep a check on your environment, thanks to its small and portable size. The data also indirectly tracks secondhand smoke and the presence of mold.

Easy Operation: The device is straightforward to use, with a one-button operation to switch it on and off. You also get a detailed instruction manual with the sensor.

Note: Keep the device running outside your home for some time before using it for the first time inside to get more accurate results.

Pros: 

  • It monitors multiple particulate matters, including PM 2.5, PM 1.0, PM10, to give you more comprehensive data.
  • This CO2 detector is simple to use and also easy to carry around.
  • An in-built auto alarm system.
  • It is pretty affordable.

Cons:

  • You cannot separately check each PMI reading as the PMI reading alternates between PM1, PM2.5, and PM10 every few seconds. Due to this,you’ll have to wait for every reading.
  • There is no data logger.

Bottom Line: 

The Langkou CO2 Detector monitors multiple particulate matters effectively at a fairly affordable price.

4. Tekcoplus Carbon Dioxide Monitor – Runner Up

Carbon Dioxide CO2 Detector Monitor Meter Tester Sensor Temperature Humidity Indoor 9999ppm NDIR Air Quality IAQ Handheld Portable Digital Wet Bulb

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The Tekcoplus Carbon Dioxide Monitor has a remote controller type of design that makes it easier to use for older people. It has a range of 9,999 ppm and also features an audible alarm when the CO2 level goes high.

Specifications:

  • Weight: 2.07 pounds
  • Color: Yellow
  • CO2 Measuring Range: 0 – 5,000 ppm

Details: 

Multiple Functions on Single Device: This device enables you to keep track of CO2 levels, relative humidity, and real-time temperature. The data output occurs every two seconds. All the real-time details and readings of the data mentioned earlier are shown on a small LED screen.

NDIR Sensor: The Tekcoplus CO2 monitor uses non-dispersive infrared technology (NDIR) for reliable and precise monitoring of CO2 levels. It measures up to 2,000 ppm with an accuracy of +/- 50 ppm.

Multiple Modes: The meter shows you normal, minimum, and maximum CO2 readings. It will also show you weighted average CO2 readings of the last 15 minutes via the STEL mode and 8 hours via the TWA mode.

Audible Alarm: This CO2 sensor has a built-in alarm that beeps whenever the CO2 level exceeds the preset value. You can customize the threshold of the alarm.

Pros: 

  • It is a very easy-to-use CO2 monitor thanks to its “remote control” design that even the less tech-savvy people can use.
  • The monitor has an in-built audible customizable alarm to alert you whenever the CO2 level goes high, which is better than being alerted by lights.
  • It can show you the average weighted CO2 levels of the last 15 minutes or 8 hours.

Cons:

  • It does not have a data logging system.

Bottom Line: 

The Tekcoplus Carbon Dioxide Monitor is a handy and straightforward CO2 monitor which is easy to use and has an audible alarm for high CO2 levels.

5. CURCONSA 3-in-1 CO2 Monitor – Runner Up

CO2 Meter, CURCONSA 3-in-1 CO2 Monitor with Ambient Temperature and Humidity, 0~5000 ppm, 2400 mAh Rechargeable Lithium Battery, Suitable for Bedroom, Office, Car.

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The CURCONSA 3-in-1 CO2 Monitor effectively tracks the CO2, relative humidity, and temperature of your room, office, or car. It is simple to use and has a minimalistic design. It can monitor up to 5,000 ppm CO2.

Specifications:

  • Dimensions: 3.23 x 1.26 x 3.23 inches
  • Weight: 5.1 ounces
  • Color: Black
  • CO2 Measuring Range: 0 – 5,000 ppm

Details: 

3-in-1: The CURCONSA CO2 meter tests the CO2 concentration of your home or office accurately and quickly. It also features a hygrometer and thermometer to monitor the indoor temperature along with humidity in real-time with high precision. 

Highly Accurate: This CO2 meter uses NDIR, also known as non-dispersive infrared technology, to detect CO2. It features full temperature range correction, high measurement accuracy, fast response, resolution up to 1 ppm, and a measurement range up to 5,000 ppm.

Warnings: The CO2 meter gives a warning that includes a three-color LED indicator light combined with a facial expression display. It makes it easier to understand the air quality. Readings of 0-700 ppm will show green light with a happy face, 700 – 1,500 ppm will show yellow light with a rested face, and 1,500 – 5,000 ppm will show a red light with a sad face (this final one is the warning sign).

Battery: You get a rechargeable lithium battery in this CO2 sensor with a capacity of 2,400 mAh. It has a standby mode for 18 hours with a battery indicator and also supports USB charging.

Minimalistic Design: The CO2 monitor has a really minimalistic appearance with a simple design and a lightweight, easy-to-carry frame. 

Included Items: The package includes a PTH Host, an English user manual, and a USB cable. 

Warranty: This CO2 detector by Curconsa comes with 12 months of warranty and lifetime technical support on any issues with the product.

Pros: 

  • It is incredibly lightweight and has a simple design for easy handling.
  • The LED lights make it easy to understand when the CO2 levels are too high or low.
  • It also shows real-time temperature and relative humidity.

Cons:

  • It has no audible alarm.
  • There is no data logging system.

Bottom Line: 

If you are in search of a straightforward and easy-to-use CO2 monitor without many complications, this is a great one for you. It is optimized for simple, daily home use. 

Buyer’s Guide

Multiple Functions 

The primary purpose of CO2 sensors is to monitor CO2 levels effectively at short intervals. Along with that, most CO2 sensors also monitor the relative humidity and temperature of your surroundings, so consider a sensor with multiple functions to get better value for your money.

Related article: 6 Best Air Quality Monitors 2021 – Buyers’ Guide & Review

Best CO2 Monitor

Data Logger

In many CO2 sensors, you will find data loggers that keep track of the data for up to a week or even more than that to give you a more thorough review. You can also download that data on your other devices. Remember, it’s not a money-related feature; hence you may find it in some affordable sensors too.

Measuring Range

Every CO2 sensor has a measuring range that ranges from 0 up to 5,000 ppm – 9,999 ppm. The higher the range, the more information you can collect.

Alarm

CO2 sensors are not just for monitoring the CO2 levels but also about alerting when circumstances are not safe. There are various types of alarm systems you can find in a CO2 sensor. Most of the alarm systems are just LED, while some of them are audible alarms that make beeping or buzzing noises. The threshold for alarm systems is usually between 1,000 – 1,500 ppm. 

Convenient to Use

You will want a CO2 sensor that is convenient for you to use according to your specific needs. Some folks might just need a sensor for their home with basic features, while others might use it for their shops or greenhouses and may require some more features like data logging. 

Frequently Asked Questions

How accurate are the best CO2 sensors?

The accuracy highly depends on which CO2 sensor you are using, but the manufacturer always provides a specified value. The sensors that use non-dispersive infrared technology have an accuracy of between ±40 ppm to ±100 ppm, ±3%.

CO2 sensor

What is the normal CO2 level for good indoor air quality?

CO2 levels between 800 to 1,200 ppm can be considered good for indoors, while anything between 1,200 to 1,500 is adequate in most places. But if the ppm goes above 1,500, this is not a good sign. The inbuilt alarms of most CO2 sensors go off at this CO2 level.

Parting Words

CO2 sensors can be life-saving if appropriately used. It is very difficult to predict when the CO2 level goes too high inside your home without an instrument, but a CO2 sensor takes care of this by alerting you when it does. Here, we have reviewed the five best CO2 sensors available in 2021, and we hope this will guide you to find a suitable CO2 sensor for your needs.

CO2 sensors are temporary solutions but having natural ventilation in your home is what you should be aiming for to take care of any excess CO2 inside your home or establishment.

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