Top 10 Best o2 sensor in 2026

Last Updated - 6/8/2026

🏆Best Choice

Kidde

Kidde Carbon Monoxide Detector, Battery Powered CO Alarm with LEDs, Test-Reset Button, Low Battery Indicator, Portable

9.8

ChoiceComparer.com Score

9.8

/ 10

Outstanding

Main highlights

•Electrochemical sensor technology detects CO gas
•Easy installation, no wiring needed, detects during a power failure by operating on 2-AA batteries (included); Install on a wall of your home or place on a tabletop
•Green LED indicates power to the carbon monoxide detector, while an 85-decibel alarm & a red LED indicates the presence of carbon monoxide
•Event Memory records the last time carbon monoxide was detected or when the unit was last tested

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$23.44

$27.57

-15%

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SHYEEH

Carbon Monoxide Detectors, CO Detector Battery Powered, Carbon Monoxide Alarm with Sensitive CO Sensor, LCD Display and Sound Warning for Home, Bedroom, Kitchen

9.7

ChoiceComparer.com Score

9.7

/ 10

Outstanding

Main highlights

•High Accuracy and Reliability:Shyeeh carbon monoxide detectors has a built-in advanced electrochemical sensor that detects dangerous CO levels more accurately and alarm more quickly.
•Alarm Criteria:Safeguard your home with Shyeeh co detector specific alarm thresholds: 50ppm (alert within 60-90 mins), 100ppm (within 10-40 mins), and ≥300ppm (within 3 mins). In case of danger, the carbon-monoxide detectors gives an alarm of no less than 85dB to 215-430ft²(20-40m²) to alert you.
•Bttery Pwered,Easy to Istall:You can mount carbon monoxide alarm on the wall or ceiling with screws (Include). Powered by 3 * 1.5V AA batteries (Not Included), no socket required, not affected by power outages, and can continuously monitor carbon monoxide levels to ensure your family's safety.
•Real-time Data LCD display:The co monitor provides 24-hour real-time monitoring, making it easy to read the level of carbon monoxide in your surroundings and protect your family from an invisible threat.
•Home Protection:According to data analysed in the United States, a home fire occurs every 38 seconds. The earlier the danger is recognised, the risk of death is reduced by 50%. The carbon monoxide detectors monitor will protect your home from the dangers of CO and eliminate the need to pay high detection fees for suspected carbon monoxide leaks.

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$8.99

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Dienmern

CO2 Carbon Dioxide Detector, Dienmern Portable Air Quality Monitor Indoor, 1600mAh Powerful Battery CO2 Monitor for CO2, Temp(°F), Humidity, LED Display CO2 Detector for Travel/Office/Home/Grow Tents

9.5

ChoiceComparer.com Score

9.5

/ 10

Outstanding

Main highlights

•【CO2 monitor】 This CO2 monitor keeps track of CO2, AQI, temperature, and humidity in real time. It’s made to give you clear, easy-to-read info at a glance, so you can stay on top of your indoor air quality and keep your space healthier and more comfortable.
•【Swiss-Made High-Precision CO2 Sensor】 Built with a Swiss-made CO2 Sensor, this air quality tester gives you highly accurate CO2 readings every second. With a wide detection range of 400–5000 ppm and accuracy of ±50 ppm, it keeps you informed of changes in your air. Plus, the added temperature and humidity sensors provide complete indoor monitoring for a healthier environment.
•【Life-Saving CO2 Alarm】 This smart CO2 detector helps protect you from hidden dangers like gas leaks, wildfire smoke, or poor ventilation. The moment CO2 levels climb above safe limits, it sounds a loud alarm right away—so you have time to react and keep your loved ones safe
•【Built-in 1600mAh Battery】 With a built-in 1600mAh lithium battery, this air quality monitor can run for up to 72 hours on a single charge. It supports USB charging and is lightweight enough to carry around, while also perfect for keeping in one spot at home or the office.
•【Smart Visual Display】 This indoor air quality monitor comes with a bright LED screen that shows CO2, AQI, temperature, and humidity in real time. The clear visuals and high contrast make it easy to read at a glance, anytime—day or night—so you always know what the air around you is like.
•【Necessity of Air Quality Monitoring】Low levels of carbon dioxide detector are generally harmless, but when the concentration exceeds a certain limit, it can affect breathing in humans and other living organisms. In severe cases, it can even become life-threatening. Therefore, monitoring CO2 levels in the air is essential for maintaining a healthy environment.
•【Note】Dear customer, just a heads-up: CO2 meters can have a little variation of around ±50 ppm. That’s simply because each CO2 meter uses a different sensor, so the readings might not be exactly the same. Thanks for your patience and understanding.

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$23.99

$25.99

-8%

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SAF

SAF Aranet4 Home: Wireless Indoor Air Quality Monitor for Office or School (CO2, Temperature, Humidity and More) Portable, Battery Powered, E-Ink Screen, App for Configuration & Data History

9.4

ChoiceComparer.com Score

9.4

/ 10

Excellent

Main highlights

•BREATHE EASILY: Aranet4 CO2 meter measures CO2 levels, temperature, relative humidity, and atmospheric pressure in real-time, empowering you to make informed decisions for healthy ventilation. No wonder it's the top-rated indoor air quality monitor in Amazon's CO2 monitor segment!
•CABLE-FREE: The power-efficient e-ink display guarantees an extended battery life of up to 4 years for this wireless air quality monitor, ensuring worry-free monitoring without the hassle of cables and cords.
•EASY-TO-USE: The color coding, prominent CO2 number on the display, and optional buzzer of this air quality meter alert you when the CO2 concentration becomes too high.
•FREE & INTERACTIVE APP: A smartphone application for viewing and analyzing up to 90 days of historical data from your indoor air quality meter, complete with user-friendly graphs.
•PREMIUM QUALITY: Aranet4 carbon dioxide detectors use nondispersive infrared sensor (NDIR) technology for the most precise and reliable CO2 measurements. Made in the European Union.
•ENJOY THE HEALTH BENEFITS: Air quality monitor indoor use helps people take better care of the atmosphere around them, leading to improved focus, mood, and overall well-being.

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$179.00

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Temtop

Temtop CO2 Monitor Indoor air Quality Monitor Portable CO2 Meter, CO2, Temperature, Humidity Home, Office or School

9.2

ChoiceComparer.com Score

9.2

/ 10

Excellent

Main highlights

•【Multifunctional CO2 monitor】Real-time CO2 detect, humidity and temperature monitor. CO2 detection range: 400-5000PPM. Temperature detection range: -10-60°C (14-140°F). Humidity detection range: 0-99%RH.
•【Cost-effectiveness and 70 days standby】the latest Photoacoustic CO2-Sensor incorporates intelligent algorithm , offering dual detection modes and using up to 70 days ! It provides you with the most cost-effective CO2 detector.
•【Mini and Multi Application】Small and thin , easy to carry, also with a detachable stand and adsorptive back cover. You can check air quality anywhere and anytime.
•【Multiple alarm modes 】the color coding and optional alarm, will sound the warning when the CO2 concentration exceeds the limit.
•【No Disturb for a Worry-Free Life】the sound alarm can be turned off, and without backlight, no noise and light disturbances, allowing you to easily fall asleep at night.
•【What's Included】 Detector x 1, USB cable x 1, User manual x 1, Bracket or accessories set x 1.
•【Tip】 For real-time monitoring, we recommend keeping the device plugged in. This will enable real-time monitoring mode, providing you with the most accurate and timely air quality data. Please note that this is a CO2 monitor and cannot detect carbon monoxide (CO).

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$45.99

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Lunarlipes

Lunarlipes Carbon Monoxide Detectors, Portable Carbon Monoxide and Carbon Dioxide Detector for Travel, Mini 4-in-1 CO and CO2 Monitor with Magnetic Suction, RV CO CO2 Detector Alarm Temp/Hum Sensor

9.1

ChoiceComparer.com Score

9.1

/ 10

Excellent

Main highlights

•【PORTABLE 4-IN-1 CO ＆ CO2 DETECTOR】The portable 4-in-1 carbon monoxide detector can monitor the current CO, CO2, temperature and humidity in the air in real time. Equipped with a high-precision sensor (10-year life), the detectable CO concentration range is 0~1000PPM (±10%), the CO2 concentration range is 400~5000PPM [± (50PPM + 5%)], and the temperature range is 14~122℉ (±2.7℉) / -10~50℃ (±1.5℃), humidity range is 0~95%RH (±5%RH). The data is accurate without delay and monitored in real time.
•【CO LIGHT INDICATION & CUSTOMIZED ALARM VALUE】The carbon monoxide monitor can present 3-stage light indication based on CO concentration. 0~49PPM (green flashing=safe), 50~99PPM (yellow flashing=warning), 100~1000PPM (red flashing=danger). By default, the CO monitor will sound an alarm when it reaches 50PPM. You can double-click the "function button" to customize the CO concentration alarm threshold. Note: The device must be in the "CO" interface before entering CO custom settings.
•【CO2 LIGHT INDICATION & CUSTOMIZED ALARM VALUE】The carbon dioxide monitor can present a 3-stage light indication according to the CO2 concentration. 400~699PPM (green flashing=safe), 700~1499PPM (yellow flashing=warning), 1500~5000PPM (red flashing=danger). By default, the audio alarm sounds when it reaches 1500PPM. You can double-click the "Function Button" to customize the CO2 concentration alarm threshold. Note: The device must be in the "CO₂" interface before entering the CO2 custom setting.
•【LARGE CAPACITY BATTERY & FAST CHARGING】The MINI 4-in-1 CO detector has a built-in 1000mAh lithium battery for long-lasting power. Support QC2.0, PD3.0, AFC, USB C UFP (BC1.2 DCP CDP SDP) and other common fast charging protocols 10~65W charging. When the CO detector is not operated for 5 minutes, it will automatically turn on the energy saving mode (the brightness of the screen will be reduced), and you can click the "function button" to turn on the backlight.
•【OUTDOOR LANYARD & MAGNETIC SUCTION】The bottom of the CO CO2 air quality monitor can be placed freely, you can put it on the table in the living room, kitchen, bedroom, etc. And it is equipped with a special outdoor lanyard, which is convenient for you to carry and use in outdoor activities such as travel, camping, picnic, and adventure. There is also a magnetic function on the back of the CO CO2 monitor, which can be attached to any metal area such as home appliances or cars.
•【SHOP WITH CONFIDENCE】Your satisfaction is our top priority. We provide 3 years service and lifetime technical support for our portable CO CO2 detector. If you encounter any problems, just contact us through Amazon Customer Service or Q&A and we will reply within 12 hours. Risk-free shopping. Customer satisfaction is our tireless pursuit.

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$49.99

$59.99

-17%

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U UNNI

U UNNI CO2 Monitor Carbon Dioxide Detector for Home, 3 Adjustable Volume for Alerts & 3 Adjustable Backlight, Photoacoustic Sensor for Temperature Humidity & Indoor Air Quality Monitor

8.9

ChoiceComparer.com Score

8.9

/ 10

Great

Main highlights

•CARBON DIOXIDE DETECTOR for HOME, SWITCH °C/°F – Great item for any home to monitor the weather and air quality! Real-time CO2 value, temperature and humidity, CO2 history chart, CO2 Concentration range, 3 Adjustable Volume for Alarm Setting & 3 Adjustable Backlight, Max/Min Data, Low battery indicator.
•HIGH-PRECISION SENSIRION CO2 SENSOR – Equipped with Swiss-made Photoacoustic Sensor provides precise and reliable readings, which gives you peace of mind about the air in your home. CO2 detection range：400～5000PPM,accuracy：+/- 5% + 50PPM. Temperature range: 14.2°F ~ 122°F, Humidity range: 20% to 95 %.
•IMPROVE VENTILATION – Very useful for high concentration of poor air quality and cooking indoors and it will indicate to open a window/door to refresh the area to get the levels lower. CO2 monitor for Home, RV, Grow Tents.
•INDOOR AIR QUALITY MONITOR - Detect rise and decrease in carbon dioxide level, perfect for anyone wanting to monitor air quality! Elevated CO2 can cause symptoms like headaches, drowsiness, allergies and difficulty concentrating, to keep an eye on air quality at home or work!
•USB POWERED OPTION & BATTERY BACKUP & ADJUSTABLE BACKLIGHT – It is plugged in which allow the multi brightness display to stay on all the time, if you prefer. Either set it on tabletops, or mount it on the wall. 3 x AAA Battery(not included) for Backup & outdoor manual calibration.
•calibration process:Place the device in a standard calibration environment of 400PPM,Press and hold the ALERT button, and power on the device or install the battery,The device will sound "Bi-BI" and the screen will display the "CAL" character and keep blinking,After three minutes of calibration, the "PASS" character will be displayed. Power off and power on the device.

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$39.99

$59.99

-33%

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AC Infinity

AC Infinity CO2 + Light Sensor, Exclusively Assists Controller AI+ Dynamically to Learn and Manage Equipment; CO2 Data Tracking Enables Smart Fan Programming for Optimized FAE, Day & Night Scheduling

8.8

ChoiceComparer.com Score

8.8

/ 10

Great

Main highlights

•This sensor is designed specifically for AC Infinity AI controllers to help monitor CO2 levels through adaptive automated learning.
•CO2 sensor pairs with AI Controllers and our Wi-Fi enabled app to precisely control and disperse carbon dioxide within grow spaces based on the most beneficial light cycle.
•Custom CO2 and fan programming dynamically alternate to activate in response to carbon dioxide levels and optimize FAE (Fresh Air Exchange).
•Additional programming includes day & night scheduling, precision cycling, and environmental data tracking.
•Smart programming can set minimum intake speed to improve efficiency of plant environment based on PPM.

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$49.99

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Teyleten Robot

Teyleten Robot SCD41 Gas Sensor Module CO2 Carbon Dioxide Temperature and Humidity Gas Sensor Module I2C

8.6

ChoiceComparer.com Score

8.6

/ 10

Good

Main highlights

•Supply voltage range: 2.4-5.5 V
•High accuracy: ± (40 ppm+5%)
•Digital I2C interface
•Integrated temperature and humidity sensors
•Low power operation to <0.4 mA average @ 5 V, 1 meas./5 min
•SCD41:400-5000 ppm

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$27.88

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INKBIRDPLUS

INKBIRDPLUS Portable CO2 Detector, Mini Indoor CO2 Monitor, NDIR Sensor with Full Color LCD, for Home, Office, Travel (PTH-10C)

8.5

ChoiceComparer.com Score

8.5

/ 10

Good

Main highlights

•High-Quality CO2 Detector: This portable CO2 meter uses an advanced NDIR sensor to detect carbon dioxide through infrared sensing technology, with high precision, strong anti-interference and excellent stability
•CO2 Concentration Level: There are three indicator lights on this carbon dioxide monitor - green light for good (400~699ppm), yellow light for medium (700~1499ppm), red light for danger (1499~5000ppm)
•Audible Alerts & Custom Alert Values: When the detected CO2 concentration exceeds 1500ppm, the device will also send out an alarm to remind you. And the CO2 alarm value is customizable
•Portable and Long-Lasting: Small and portable, the included lanyard allows you to take this portable CO2 sensor anywhere. Built-in 1000mAh lithium battery, it can be fully charged within 3 hours, and the battery life is about 72 hours
•HD Full-Color LCD Display: Full-color LCD display, clear and easy to read, eye protection. If there is no operation for 5 minutes, it will automatically enter the energy-saving ECO mode
•Wide Application: Contains 1x CO2 detector, 1x lanyard, 1x 2m charging cable and user manual. This portable CO2 monitor is suitable for home, office, grow tent and more
•NOTE: We recommend that when using the detector for the first time, place the device in an open and uninhabited environment and manually calibrate it once to avoid inaccurate readings

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$30.09

$42.99

-30%

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