Best CO2 Monitor: Indoor Air Quality Monitors

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If you spend long periods inside at home or work, you need to start thinking about your indoor air quality.

Monitoring carbon dioxide (CO2) levels has become an essential way to control ventilation and maintain healthy indoor air.

If CO2 levels get too high, it can lead to slower cognitive function, poor sleep, and headaches.

In this post, we will explain why CO2 monitoring is essential, compare the top-rated CO2 detectors, and provide tips on choosing the right CO2 monitor for your needs.

Let’s get into it!

Best Overall: SAF Aranet4 Home
Budget-Friendly: Lankou CO2 Carbon Dioxide Detector
Best Portable: INKBIRDPLUS Portable

What is a CO2 Monitor?

A CO2 monitor is a device that measures the concentration of carbon dioxide gas in the air.

As you exhale CO2 or perform activities that release CO2 like cooking, higher indoor CO2 levels indicate insufficient ventilation and stale, unhealthy air.

Most CO2 monitors use an NDIR (non-dispersive infrared) sensor to detect CO2 concentrations accurately.

This allows you to track indoor CO2 levels and adjust ventilation to optimize air quality and comfort.

Related: Bryan Johnson Air Filter Recommendation

Why You Need a CO2 Monitor

Best CO2 Monitor Air Flow Diagram
Example of a Home Airflow Diagram

If you’re reading this, chances are you suspect your indoor air quality might be a problem.

Below, I’ve highlighted some of the top reasons folks buy one of these monitors.

  • Detect inadequate ventilation, leading to “sick building syndrome”
  • Improve health by preventing excessive CO2 buildup
  • Increase productivity by keeping CO2 levels optimal
  • Provides air quality feedback for ventilation adjustments

Basically, you need to know if CO2 levels are high so you can take action to lower them.

CO2 ConcentrationCognitive Function and AlertnessProductivity Impact
400-600 ppmBaseline for outdoor air quality; highest cognitive functioning and alertness.Optimal
600-1,000 ppmSlight decrease in cognitive function; may not be noticeable to all individuals.Mildly Reduced
1,000-2,000 ppmFurther reduced cognitive function; increased sleepiness and decreased concentration.Moderately Reduced
2,000-5,000 ppmSignificant reduction in cognitive function and alertness; headaches, sleepiness, and stagnant, stale, stuffy air; reduced attention span.Significantly Reduced
> 5,000 ppmSerious oxygen deprivation may occur leading to rapid fatigue and severe lack of focus; decision- making ability compromised.Severely Reduced

This can be as simple as opening a window, ventilating when cooking, or keeping doors open.

The bottom line is that controlling indoor CO2 levels through monitoring is vital for creating healthy, productive indoor spaces.

Related: Best Warm Mist Humidifiers

Features to Consider When Buying a CO2 Monitor

Best CO2 Monitor Air Flow Diagram

When selecting a carbon dioxide monitor for your home or office, there are several key features to evaluate to ensure you choose the right product for your needs.

Related: CO2 Tolerance Test: A Comprehensive Guide


The most critical specification to consider is measurement accuracy.

After testing several products, there is a 50-150 ppm disparity in CO2 readings.

Most monitors use the same type of NDIR sensors, which offer the greatest accuracy.

The best practice is to use CO2 tracker readings directionally rather than the precise figure.

Data Logging

The ability to record and store CO2 measurements at set intervals allows you to monitor trends and identify recurring periods of high CO2.

This data can inform ventilation adjustments and other strategies to optimize air quality.

Most monitors that include this feature require WiFi connectivity.

Our top pick offers the most well-reviewed data logging capability.


CO2 monitors with integrated WiFi or Bluetooth allow you to access real-time CO2 data remotely via smartphone, tablet, or computer.

This enables you to closely track indoor air quality from anywhere and make ventilation adjustments even when not on-site.

Connectivity also aids in the central monitoring of multiple monitors across large homes or office buildings.

Our top pick lets you track several CO2 monitors within the same household.


Having an easy-to-read display lets you quickly check CO2 levels at a glance.

Large, high-contrast LEDs or LCDs are placed visibly on the monitor.

Our top pick features an e-ink display, which uses a significantly lower battery.

Most LED devices last 2-3 days, while e-ink displays last up to 5 years.

Audible alerts for high CO2 are helpful but can also be annoying if the CO2 threshold is set too low. It’s woken me up a couple of times.


Most CO2 monitors are powered by USB and offer flexibility in placement around your home or office.

Most likely, you will want to keep the minor connected to a power outlet 24/7.

If you don’t want to worry about charging or changing batteries, our top pick offers an insane 4-5-year battery life with no charging.

Best CO2 Monitor

SAF Aranet4 Home (Best Overall)

Overall Top Pick
SAF Aranet4 Home: Wireless Indoor Air Quality Monitor for Office or School
£169.00 £149.00
  • 5-year battery life (no charging)
  • Elegant e-ink display
  • Smartphone connection
04/03/2024 09:01 pm GMT

The Aranet4 stands out for its precision, design aesthetic, and battery life.

Once calibrated, which is a simple process, it closely matches more expensive units in measuring CO2, temperature, and humidity.

It’s reliable too, using advanced NDIR sensor technology to ensure the readings you get are trustworthy.

Long-Lasting and Easy to Use

With its e-ink display, the Aranet4 combines clarity and energy efficiency, giving you up to five years of battery life.

It’s designed for ease, alerting you with color-coded readings and an optional buzzer when CO2 levels get too high.

Portable and App-Connected

This monitor is small enough to be taken anywhere, even on flights. It pairs with a straightforward app for your smartphone, letting you track and analyze air quality history for the past 90 days.

While the app doesn’t offer dark mode and could be quicker, it works well for daily use.


The Aranet4 is on the pricey side, but its accuracy justifies the cost.

It’s a solid choice if you’re after a detailed understanding of your indoor air quality without the need for professional equipment.

Keep in mind, it uses Bluetooth, not Wi-Fi, so you’ll need to be within range to connect.

If you’re in the market for a reliable, easy-to-use air quality monitor that goes where you do, the Aranet4 is worth a look.

Lankou CO2 Carbon Dioxide Detector (Budget-Friendly)

The Lankou CO2 Detector is a dependable tool for those on a budget who still want accuracy.

It has ans NDIR sensor.

It’s also equipped with semiconductor sensors for monitoring temperature and humidity, offering a more sensitive and stable readout.

User-Friendly Design

With a large, colorful LCD screen, the readings are easy to see at a glance, making it a user-friendly option for any indoor space.

The device’s compact size and hollow back design enhance portability and airflow, and despite its simple appearance, it delivers where it counts: in performance.

Portable with a Warning System

It’s built with a 1600mAh battery, which allows for about 8 hours of continuous use on a full charge—sufficient for most daily needs.

When CO2 levels exceed a certain threshold, the detector sounds an alarm, reminding you to ventilate the area, keeping your indoor air quality safe.

Design Quirks to Consider

While it offers a good price-to-performance ratio, there are a couple of design choices to be aware of.

The detector’s physical design, with a slanted back and round top, means it isn’t the most stable when placed on a flat surface and can’t easily be secured with tape.

Also, the bright screen lacks a dimming feature, which might be too intense for nighttime bedroom use.

Final Thoughts

Despite its minor quirks, the Lankou CO2 Detector is recommended for its reliable CO2 sensing capabilities.

If you need a cost-effective way to keep tabs on air quality without sacrificing accuracy, this could be the right device for you.

INKBIRDPLUS Portable (Best Portable Option)

The INKBIRDPLUS CO2 Meter stands out for its portable design and high-quality NDIR sensor, offering accurate and stable carbon dioxide detection.

Its infrared sensing technology is less prone to interference, giving you reliable readings wherever you go.

Clear Indication System

The three-color indicator system makes understanding air quality simple:

  • Green signals good air (400 – 699 ppm)
  • Yellow indicates moderate levels (700 – 1,499 ppm)
  • Red warns of high CO2 concentrations (1,499 – 5,000ppm)

This straightforward approach demystifies air quality monitoring.

Tailored Alerts

Not only does the detector alert you when CO2 surpasses 1,500 ppm, but it also allows for customizable alarm thresholds.

This means you can set the alert to a level that’s specific to your comfort and safety requirements.

Long Battery Life in a Compact Form

With a 1,000 mAh battery that charges in just 3 hours and lasts up to 72 hours, this detector ensures you’re not constantly tethering to a power source.

Its compactness, paired with a handy lanyard, makes it truly mobile.

User-Friendly Display

The HD full-color LCD display is designed for clarity and eye comfort.

If inactive for 5 minutes, the detector smartly shifts to ECO mode to conserve energy without sacrificing performance.

Versatile and Practical

This CO2 monitor’s ease of use and quick response to changing conditions make it ideal for managing indoor air quality.

Whether it’s for home, office, or a grow tent, the inclusion of a long charging cable and user manual makes setup a breeze.

Personal Experience and Responsiveness

Users have found this device to be consistent and responsive, noting a significant decrease in CO2 levels with proper ventilation.

It’s also been tested in various scenarios like cooking or lighting candles, proving its quick and accurate response to real-time changes in air quality.

Overall Satisfaction

Given its portability, long battery life, and efficient operation, the INKBIRDPLUS CO2 Detector is highly recommended for anyone needing to keep track of air quality on the move.

Whether you’re home or out, it seems to be a reliable tool for maintaining healthy CO2 levels and, by extension, cognitive function.

How to Maximize Your CO2 Monitor Effectiveness

Proper placement ensures your CO2 monitor provides accurate data to enhance ventilation control.

Follow these best practices:

  • Position away from drafts, vents, doors, and windows
  • Mount at typical occupant breathing height
  • Check calibration guidelines
  • Clean the monitor surface regularly
  • View real-time data and adjust ventilation

Optimizing your CO2 monitor will allow you to track and improve indoor air quality reliably.


What is the ideal indoor CO2 level?

For good air quality, indoor CO2 should not exceed 800-1000 ppm above outdoor ambient levels (typically 400-500 ppm).

How is a CO2 monitor different from a carbon monoxide detector?

CO2 monitors measure carbon dioxide levels, while carbon monoxide detectors measure the highly toxic gas carbon monoxide (CO).

Both are important for home safety and indoor air quality.

Where should I place a CO2 monitor?

Position your CO2 monitor in occupied areas and away from windows, vents or doors to properly assess indoor CO2.

Where should you not put a CO2 detector?

A CO2 detector should not be placed near windows or doors where drafts can affect the readings.

It should also be away from direct sunlight, heating and cooking appliances, or any area where pets or people may exhale directly onto the sensor, as this can give false high readings.

How many CO2 monitors should you have in your house?

The number of CO2 monitors you should have in your house depends on the size of the home and the ventilation system.

At a minimum, it’s advisable to have one in each main living area and one near bedrooms. For multilevel homes, one on each floor is recommended.

What removes CO2 from the house?

Ventilation is the primary method for removing CO2 from the house. This includes opening windows, using exhaust fans, and utilizing HVAC systems with outdoor air exchange. Plants can also absorb CO2, albeit to a much lesser extent.

What is the average CO2 level in a house?

The average CO2 level in a house typically ranges between 400 ppm (parts per million) to 1,000 ppm.

Levels above 1,000 ppm can indicate inadequate ventilation, and sustained levels above 2,000 ppm can affect human health.

What naturally removes CO2 from the air?

Plants are natural removers of CO2 from the air through the process of photosynthesis.

They absorb CO2 and convert it into oxygen, which they release into the atmosphere.

Do air purifiers get rid of CO2?

Most air purifiers are not designed to remove CO2.

They primarily filter particulate matter and pollutants from the air.

Medical Advice Disclaimer


The information, including but not limited to text, graphics, images, and other material contained on this website, are for informational purposes only.

No material on this site is intended to be a substitute for professional medical advice, diagnosis, or treatment.

Always seek the advice of your physician or other qualified health care provider with any questions you may have regarding a medical condition or treatment before undertaking a new health care regimen, and never disregard professional medical advice or delay in seeking it because of something you have read on this website.

About the Author

Drew Wilkins is a fitness and nutrition expert with a Master's in Biokinesiology (emphasis in Sports Science) from the University of Southern California and over a decade of experience as a personal trainer, nutrition consultant, and wellness coach. An avid surfer and soccer player, he brings a unique perspective to his research, advocating for a balanced approach to health that includes physical fitness, nutrition, and mental well-being.

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