Carbon monoxide meter: Cheffort Handheld Carbon Monoxide Meter, Portable Carbon Monoxide Detector, Professional-Grade CO Gas Tester with LCD Backlit Display, 0-1000PPM Range for Industrial and Home (Battery Not Included)

Best Carbon Monoxide Meter (under $100 in 2023) – Forensics Detectors

Carbon monoxide (CO) is a deadly gas. Many customers purchase CO meters to check for safe levels in the home, car, office or work and also help to determine if CO level are exceeding OSHA, WHO, NIOSH or ACGIH CO Threshold levels. Handheld portable CO meters are very popular with tonnes of models to select from. Yep, and it gets confusing when making a selection. So which is the best? Here we will provide you with the ultimate guidance and key features of what to look for when selecting a CO meter under $100. 



  • Carbon Monoxide meters are affordable and good choices exist under $100
  • Carbon Monoxide meters are handheld units that provide users with the instantaneous CO concentrations
  • Helpful in detecting leaks, indoor air quality and possible CO leakage pathways
  • Typically more sensitive and faster than UL2034 home CO detectors and CO alarms
  • Hard to objectively compare carbon monoxide meters
  • Requires expensive USA NIST Calibration gas reference to test accuracy
  • Some cheap options may be good for some applications
  • Carbon monoxide is a deadly killer and should be taken very serious

Do I Need a Carbon Monoxide Detector or a CO Meter?

It depends on your application.  

CO Detector uses typically include:

  • Home ceiling and wall mount application where a CO detector is required by state, city or county authorities. In most areas, CO alarms (UL2034) are mandatory for home owners and landlords to install in the home
  • Home use for continuous protection

Carbon Monoxide Meter uses typically include:

  • CO concentration indoor check for OSHA, NIOSH, WHO, EPA or ACGIH threshold checks
  • Suspect appliance leaking or poor indoor air quality checking
  • See prior question discussing who uses a CO meter.

What Levels of CO are Dangerous? 

The safest CO level is zero ppm. If there is CO that is detected by a Carbon Monoxide Meter or a Carbon Monoxide Detector, then it means you have a carbon monoxide leak, carbon monoxide accumulation or carbon monoxide entry into your indoor area. If there is a recording of any CO, then a change in circumstance, CO can quickly increase to dangerous levels. There are some guidelines that can be used as a safety reference. The science is changing and more low level CO exposure data is coming to light. A summary from various safety and air quality organizations are listed here:



World Health Organization (WHO)

9 ppm average over 8 hours

Environmental Protection Agency (EPA)

The Clean Air Act requires EPA to set national ambient air quality standards (NAAQS)

9 ppm average over 8 hours

The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE)

9 ppm average over 24 hours

National Institute for Occupational Safety and Health (NIOSH)

35 ppm average over 10 hours

200 ppm ceiling value

Occupational Safety and Health Administration (OSHA)

50 ppm average over 8 hours

American Conference of Governmental Industrial Hygienists (ACGIH)

25 ppm average over 8 hours

CO Detector Alarming Protocol

UL2034 (USA)

> 70 ppm (60 to 240 minutes)

> 200 ppm (10 to 50 minutes)

> 400 ppm (4 to 15 minutes)

CO Detector Alarming Protocol

EN 50291:2001 (Europe)

> 50 ppm (60 to 90 minutes)
> 100 ppm (10 to 40 minutes)
> 300 ppm (3 minutes)

Forensics Low Level Carbon Monoxide Detector

> 25 ppm (1 minute)

How Accurate Are Carbon Monoxide Meters?

Typically the accuracy of a Carbon Monoxide Meter is specified in the CO user manual. These values vary. They way in which accuracy is specified and communicated to the user also varies. These numbers should also be taken with a grain of salt since our internal testing (see the video above), shows large variance. Some detectors do not comply with their own accuracy specifications. Nevertheless, accuracy specs are typically presented in three ways:

Absolute ppm Error Reading

  • Example: accuracy: +/- 10ppm
  • In this example, a simple +/-10ppm blanket error is stated. This means that if your CO meter is reading 100ppm, then the actual reading is expected to be between 110ppm to 90ppm.

Percentage Error Reading

  • Example accuracy: +/- 10% (of the reading)
  • In this example, a percentage of the reading is stated. If your CO meter is reading 200ppm, then the actual reading should be expected to be either +/- 10% of 200ppm. Which is between 220 ppm or 180 ppm.
  • If a blanket percentage is provided, be skeptical. The manufacturer should have been more specific and the follow up question to that spec would be, “. the accuracy % of the reading or of the full scale?”.

Percentage Full Scale Error Reading

  • Example accuracy: +/- 5% F.S. (full scale error)
  • In this example, the error is based on the full scale range of the detector. For example, if the detector is rated at 0-1000ppm and it is reading at 100ppm, then 5% of 1000 ppm is 50ppm, hence the reading could be between 150 to 50ppm.
  • Although this sounds very large and “really bad”, most detectors fail error readings since temperature and humidity and the largest error sources, especially in the extreme ends of the temperature and humidity specifications.  
  • Most Carbon Monoxide Meters (and other toxic gas detectors) use this scale to reference accuracy and error.

Do Carbon Monoxide Meters have Alarms?

Most CO meters do have alarms. They are typically set to the OSHA, NIOSH, EPA or ACGIH CO exposure thresholds. Typical alarms include LED, buzzer and vibration. A solid Carbon Monoxide Meter will have all three types of alarms for added safety – think about using it in a mine which is very noisy and clipped to your pocket so you may not see it. In that case, the vibration alarm may save your life. Some carbon monoxide meter allow the user to change the alarm thresholds.

What is the Difference Between a CO and CO2 Meter?

Never confuse CO and CO2. They are both totally different gases. A carbon monoxide meter does not measure carbon dioxide gas and a carbon dioxide meter does not detect carbon monoxide gas. CO and CO2 are completely different gases and require specific meters to detect each respective gas. 

We see often customers confusing CO with CO2. This is a Amazon review by a customer incorrectly comparing the results of a CO and CO2 monitor device. Dangerous and bad mistake!

Should a Carbon Monoxide Meter Read Zero?

Yes it should but not all Carbon Monoxide meters have the zero calibration function.

Zeroing a Carbon Monoxide meter means to force the unit to read zero when it is in a zero carbon monoxide environment – typically done in the fresh outdoor air. Sometimes you will notice your carbon monoxide meter flickers between 0,1,2,2,1,0,2, etc… or it may stay at 2ppm when in the outdoor air. Assuming the outdoor air is fresh and has no CO, then the CO meter should be zeroed to improve its accuracy.

Also if you are curious what your outdoor CO level is, we recommend checking it here.

Step 1: Get yourself a good CO meter.

Step 2: Make sure it works. Give it a bump test. 

Step 3: Turn it ON. Most CO meters start operating and showing you the instantaneous CO ppm reading. It should read 0 ppm.

Step 4: Take it to the desired indoor areas for testing. Keep it stationary for at least one minute to obtain stable readings. Ensure you are not breathing on it, nor changing temperature or humidity. Do not stick it in the oven, expose it to chemicals, exhaust or any “harsh” dynamic change in environment – why? it will react and give you false CO readings. The CO sensor element is very sensitive and fragile.

Step 5: Take photos or videos if you want to send any of the test results to somebody.

How Do You Test the CO Meter Accuracy?

To test the accuracy of your CO meter you need to use a reference gas. This would be USA NIST traceable source gas that can be purchased from various gas companies including from us (supplied via GASCO). This is how you do it:

Step 1: Order CO gas. For example, 200ppm of CO gas.

Step 2: You will receive your calibration gas cylinder. The COA will tell you the exact CO level made. It is never exactly the same as ordered, just a bit off. It could be 204ppm.

Step 3: You may need to use a calibration cap, hood to deliver the gas to the sensor. Deliver the calibration reference gas to the sensor. Allow the sensor to stabilize for about 1 minute and take your reading. 

Step 4: Assume the reading is 210ppm. Then the CO meter is 6 ppm away from 204ppm. This is a 2.9% error compared to the reading. Or it can be interpreted as a 0.6% error to full range (F.S.) if the CO meter has a range of 0-1000ppm.

How Much Do CO Meters Cost?

An excellent CO meter will cost no more than $100. However, if you need a CO meter with a built in pump, it is more expensive and will cost about $300.

Where Can I Buy A Carbon Monoxide Meter?

CO meters are readily available online from or Also a tonne of products options, for all applications are available from us.

Final Words

  • CO meters are affordable and good choices exist under $100
  • Carbon Monoxide meters are handheld units that provide users with the instantaneous CO concentrations
  • CO Meters are helpful in detecting leaks, indoor air quality and possible CO leakage pathways. Also excellent to determine if any OSHA, EPA, NIOSH or ACGIH level have been exceeded
  • Typically more sensitive than home CO detectors complying with UL2034
  • Hard to objectively compare CO meters unless you have USA NIST Calibration reference gas
  • Some cheap options may be good for some applications
  • Carbon monoxide is a deadly killer and should be taken very serious 

About The Author

Dr. Koz is the President of FORENSICS DETECTORS where the company operates from the scenic Palos Verdes Peninsula in Los Angeles, California. He is a subject matter expert on gas sensor technology, gas detectors, gas meters, and gas analyzers. He has been designing, building, manufacturing, and testing toxic gas detection systems for over 20 years.

Every day is a blessing for Dr. Koz. He loves to help customers solve their unique problems. Dr. Koz also loves spending time with his wife and his three children going to the beach, grilling burgers and having a cold beer. 

Read more about Forensics Detectors here.

Email:  [email protected]
Phone: +1 424-341-3886

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    Carbon monoxide detector

    Carbon monoxide (CO) detectors with alarm –

    You can share the article in social networks and instant messengers:

    We often receive a request for a carbon monoxide detector with an alarm. These sensors are suitable for various applications.

    There are household
    detectors (kitchen, sauna, home, tent and other)

    For solution
    such tasks should be addressed to Aliexpress,
    E-bay, Alibaba and similar resources.

    However, we
    specialize in offering CO detectors for industrial applications for

    We have
    several options for offering carbon monoxide alarms.

    several possibilities to signal the excess of CO. Therefore, when
    Forming a request, we are interested in the task facing the customer.

    In some cases
    a meter is offered, to which it is connected via a cable
    signaling device (usually an indicator and an audible buzzer are used). For solutions
    problems in this way as an instrument is proposed GS

    Another solution
    control can be the use of CO signaling device VOX-33 with

    VOX-33 is used to measure
    CO in mines, tunnels, mines. Our employees have implemented several
    projects using a modification of the carbon monoxide converter for mines VOX-33. The device has
    built-in detector-signaling device, which is programmed to a certain level
    exceeding the gas content indicators, after which it gives an audible signal.

    a certain skill when working with CO converters. To prevent false alarms,
    when installing the meter, the instruction manual for the detector is attached
    carbon monoxide with instructions for setting the CO alarm.

    In case
    the use of carbon monoxide alarms in mines, tunnels, mines, mining
    workings, CO signaling devices can be used as part of complexes,
    controlling other parameters of the microclimate – CO2, humidity, temperature,
    air flow rate in the mine…

    it is required to install a carbon monoxide and natural gas methane sensor.

    For complex
    control of the air environment our specialists have developed the Aeroton station.
    The station is equipped with a CO detector-signaling device, humidity converter,
    air temperature and CO2 content. Other devices are connected and
    installed optionally.

    Often the signaling needs to be duplicated or displayed on a remote operator’s PC. To do this, we recommend the communication unit Courier-78, which collects data and transmits the results of measurements via cable to the local network of the enterprise.

    results is also possible with the help of wireless data transmission using
    Alter systems.

    Measurement results,
    received on the operator’s PC are displayed in specialized software, which
    signals the excess of CO concentration visually, audibly or by activating
    emergency alert system. Our organization is ready to provide
    software solutions and specialized software if necessary.

    stand alone proposals to close requests for a carbon monoxide sensor in
    garage. If we are talking about a private garage, then it makes sense to look for a solution in
    online stores. There you can buy an inexpensive household alarm
    CO gas contamination is cheap.

    If a garage CO meter is required to organize warnings in underground garages or parking lots, then we are ready to offer the GM-44 detector.