Carbon Monoxide meters are crucial tools when it comes to carbon monoxide (CO), a deadly gas that can accumulate in homes, cars, offices, and workplaces. Handheld portable CO meters are popular tools for monitoring CO levels and ensuring they remain within safe thresholds set by organizations like OSHA, WHO, NIOSH, and ACGIH. With numerous models available, selecting the best CO meter under $99 can be confusing. To make an informed choice, consider key features such as accuracy, response time, durability, and ease of use. By prioritizing reliable gas detection and investing in a quality CO meter, you can protect yourself and others from the potentially fatal consequences of carbon monoxide exposure.
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TOP 5 Carbon Monoxide Meters < $89 (2024)
TOP 5 Carbon Monoxide Meters < $100 (2023)
2023 Best Carbon Monoxide Meter for under $99?
In 2023, we have tested 5 popular carbon monoxide meters from Amazon.com and Walmart.com. These are also still available on Amazon in 2024 so still relevant. We undertook a systematic analysis that included:
- traditional unboxing to see each CO meter, associated accessories and documentation
- performed a functional test to observe the ergonomics, functionality, and intuitive operation of the CO meter
- performed an accuracy test to NIST traceable carbon monoxide reference gas (196ppm)
Our ultimate objective in doing this test is to walk you through the items to consider, questions to ask and first hand information to help with you knowledgeable selection when purchasing a handheld CO meter.
#5 DOEATOOW CO Carbon Monoxide Detector (2023)
Price: $60-$80
Accuracy: ⭐⭐
Functionality: ⭐⭐⭐⭐⭐
- This is a reasonable option as a handheld CO tester. Unfortunately, in our testing, it did not maintain a steady state CO level when exposed to NIST CO reference gas - it had a slight drift towards the downside.
- Advanced functions such as alarm setting and calibration which is a huge plus.
- Excellent value for money, this carbon monoxide meter comes with a made in UK sensor with USB recharge.
- There is no NIST USA traceability documentation, no date of manufacture, and no test engineer QC signature.
#4 Carbon Monoxide Meter PCMM05 - Pyle USA (2023)
Price: $80-$100
Accuracy: ⭐
Functionality: ⭐⭐⭐
- A popular brand that has been around for many years.
- Offers basic functionality but overly sensitive and the least accurate unit that was tested.
- Comes with an excellent made in Japan sensor from Nemoto, but seems the detector is calibrated to read "too sensitive".
- Also another annoying thing was that the unit arrived with a dead battery.
- There is no NIST USA traceability documentation, no date of manufacture and no test engineer QC signature.
#3 SMART SENSOR Handheld Carbon Monoxide Meter (2023)
Price: $30-$40
Accuracy: ⭐⭐⭐⭐⭐
Functionality: ⭐⭐⭐
- Another famous model that is the best bang for buck when it comes to CO meters.
- Offers basic functionality, comes with an excellent made in Japan sensor from Nemoto and is very accurate within specifications.
- For those on the slimmest budget, this is the unit to grab and you will not be disappointed.
- Documentation is not consistent, but may just be nuisance typos.
- There is no NIST USA traceability documentation, no date of manufacture and no test engineer QC signature.
- Unfortunately, the ergonomics of the unit are not the best, it does feel like a toy to the touch and did not arrive with any batteries.
#2 Klein Tools ET110 CO Meter, Carbon Monoxide Tester (2023)
Price: $90-$100
Accuracy: ⭐⭐⭐⭐
Functionality: ⭐⭐⭐⭐
- A very popular and trusted brand in the tool industry.
- A unique model and operated within specification, but under represented when tested to the reference CO gas.
- I personally love the feel of the unique as it has a rubberized case and comfortable feeling.
- A bit too long in length for my preference.
- Offers basic functionality with temperature and averaging for STEL.
- Comes with a made in Japan sensor (largest form factor compared to the others) from Figaro (5 year sensor), which is the worlds oldest and most famous gas sensor company.
- There is no NIST USA traceability documentation, no date of manufacture, and no test engineer QC signature.
#1 Forensics Detectors Carbon Monoxide Meter (2023)
Price: $90-$100
Accuracy: ⭐⭐⭐⭐⭐
Functionality: ⭐⭐⭐⭐⭐
- Has all the bells and whistles features like all other tested
- Most important comes with the USA NIST traceability documentation, and the only unit at this price point.
- The most accurate unit tested, only off by 1ppm to the reference gas used in the testing.
- A bit more pricey due to extra work needed to calibrate to NIST standards and produce the USA certificate, since some customers need it for OSHA or regulatory evidence of calibration.
2024 Best Carbon Monoxide Meter for under $89?
In 2024 we tested a further x5 popular carbon monoxide meters from Amazon.com. Our analysis included:
- unboxing to see what is in each box, accessories and documentation
- performed a functional test
- performed an error test to NIST traceable carbon monoxide reference gas (200ppm)
#1 Forensics Detectors Carbon Monoxide Meter (2024)
Price: $80-$90
Accuracy: ⭐⭐⭐⭐⭐ (200ppm versus 205ppm) less than 3% error
Functionality: ⭐⭐⭐⭐⭐
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This is the classic CO Meter by Forensics Detectors. We have sold thousands of these reliable Carbon Monoxide Meters. They offer advanced features and feel professional and durable. Most important they are tested and calibration in the USA.
✅ Good Response and Excellent Accuracy
✅ Can adjust alarm levels
✅ Calibration Certificate incuded (with signature and date)
❌ Most expensive
#2 Tadeto Carbon Monoxide Meter (2024)
Price: $40-50
Accuracy: ⭐⭐⭐⭐⭐ (200ppm versus 218ppm) less than 10% error
Functionality: ⭐⭐⭐⭐
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This is an excellent low cost option for a handheld digital CO Meter. The unit performed well in our independent testing to reference NIST CO Gas. 200ppm versus 218ppm with less than a 10% error is excellent for this price point. When breaking down the unit, we found a nice Made in Japan Nemoto CO Sensor which is a high quality carbon monoxide sensing element that is well respected within the gas measurement community. Unfortunately it does not arrive with a calibration certificate (unfortunate missed opportunity).
✅ Good Response and Good Accuracy within specifications
✅ Can adjust alarm levels
✅ No Auto Off
✅ Made in Japan CO sensor element
❌ No Calibration Certificate. No Quality Control Certificate
❌ No Calibration functionality
#3 HAKINAKU Carbon Monoxide Meter (2024)
Price: $30-$40
Accuracy: ⭐⭐⭐ (200ppm versus 236ppm) over 10% error
Functionality: ⭐⭐⭐
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An cheap price but questionable performance. It was very sensitive, too sensitive which is concerning that no quality control exists. A cute CO detector that will do that job, but not for the serious HVAC, plumber or industrial hygienist.
✅ Good Response and over-calibrated (200ppm versus 236ppm)
✅ Nice color display
❌ Error is high and over-specification
❌ No Calibration Certificate. No Quality Control Certificate
❌ No Calibration Adjustment Feature
❌ 50ppm fixed alarm level (not adjustable)
❌ 1 min auto-off annoyance
❌ FAILED - CEKKIENA Carbon Monoxide Detector (2024)
Price: $30-$40
Accuracy: ⭐ (200ppm versus 135ppm) over 30% error
Functionality: ⭐⭐⭐
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An excellent price but terrible performance. It does react to CO gas, however, very far from where is should be and in addition was nowhere near the specification described regarding accuracy. A small unit, pocket sized, but for such a low price, comes low accuracy performance. Avoid it if you take CO exposure serious.
✅ Nice display
❌ Error is high and under-specification over 30% error
❌ No Calibration Certificate. No Quality Control Certificate
❌ No Calibration Adjustment Feature
❌ 50ppm fixed alarm level (not adjustable)
❌ 1 min auto-off annoyance
❌ FAILED - GRAY RHINO Carbon Monoxide Pen Style Detector (2024)
Price: $15-$20
Accuracy: ⭐ (200ppm versus 99ppm) over 50% error
Functionality: ⭐
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Was so cheap it was too good to be true. Indeed it was. Error was terrible on the verge of being a very dangerous product. The design and idea behind this little unit is great, but performance is terrible and should be avoided at all costs. The your money and buy lunch instead.
✅ Lowest Price
❌ Terrible Accuracy, over 50% error
❌ No Calibration Certificate. No Quality Control Certificate.
❌ No Calibration Adjustment Feature
❌ 50ppm fixed alarm level (not adjustable)
❌ 1 min auto-off annoyance
What Is the Difference Between a CO Meter and a CO Detector?
A carbon monoxide meter is a handheld portable unit that detects CO gas at lower ppm concentrations that a typical UL2034 home ceiling CO detector or CO Alarm. A CO meter is a great tool to use to locate, detect and sniff a potential CO leakage source or pathway.
CO Detectors used for home wall or ceiling mount applications that comply with UL2034 are not designed to display CO concentration less than 30ppm (that is just part of the UL2034 requirement).
In addition, a carbon monoxide detector or carbon monoxide alarm operates very "slowly" since its refresh rate is very low to conserve battery power. Also they may alarm slow since the first alarm threshold at 70ppm only triggers after a minimum of 60 minutes.
Who Uses a Carbon Monoxide Meter?
Homeowners and Landlords
Many homeowners and landlords when suspecting a CO leak purchase a CO meter to test and sniff a potential carbon monoxide source. Similarly, RV, campers and transport personnel also do the same to ensure maximum safety.
Plumbers and HVAC
Plumbers and HVAC professional are also major purchasers of carbon monoxide meters. They use this tool to confirm any cracked heater exchanges, correct ventilation, backdrafting or CO accumulation. Also helps to confirm correct appliance installation.
Industrial Hygienists
Industrial hygienists perform indoor air assessments and tests and when dealing with carbon monoxide cases they will use a CO meter or analyzer to gather necessary data to find a leak, analyze indoor air quality or determine accumulation dynamics and carbon monoxide movement.
Regulatory Inspectors, First Responders, EMS
City, County and State authorities including paramedics and first responders are frequent users of carbon monoxide meters. They use them for various requirements. For example, EMS personnel use them to protect themselves to ensure they are not entering a "self harm" toxic environment. City inspectors use them to ensure public facilities are safe to occupy.
Building Maintenance Technicians
Carbon monoxide meters are also often used by building maintenance crews. They can track accumulation of carbon monoxide in garages, facilities, pool heater rooms and other "common" CO leakage sites to ensure maximum safety of workers and occupants.
Work Safety Officers
Many companies employ dedicate safety teams, health safety and environment officers and safety specialists that are responsible to ensure all workers in an industrial, manufacturing or occupational space are safe. Regular inspections are required that include rudimentary Carbon Monoxide measurements with CO meters. Such work is particularly important in industries where combustion is occurring, manufacturing or carbon monoxide is a known affluent or by-product. Another important part is using gasoline power tools on construction sites such as saw, generators, mixers, forklifts and many other machinery that emit exhaust carbon monoxide.
Recreation, Camping, Ice Fishing
Situations where recreational activities call for propane or butane heating and cooking appliances to be used in a confined space such as camping, ice fishing and many others pose a serious threat. Use of a CO detector and a CO Meter, to determine dangerous CO indoor air quality levels is very helpful.
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:
Agency |
Limits |
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
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> 70 ppm (60 to 240 minutes) > 200 ppm (10 to 50 minutes) > 400 ppm (4 to 15 minutes) |
CO Detector Alarming Protocol
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> 50 ppm (60 to 90 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. Until they are tested and verified you must be VERY skeptical, just see the results we obtained. 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 videos above), shows large variance. More often than not, the carbon monoxide 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. In other words, the error or accuracy is with respect to the detected value presented.
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, "...is 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.
How Can I check Carbon Monoxide Levels in My Home?
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 Amazon.com or Walmart.com. Also a tonne of products options, for all applications are available from us.
Final Words
Gas detection is vital when it comes to carbon monoxide (CO), a deadly gas that can be present in various settings. Affordable handheld CO meters, with good options available under $100, provide users with instantaneous CO concentrations. These meters are essential for detecting leaks, assessing indoor air quality, and identifying potential CO leakage pathways. They also help determine if CO levels exceed safety thresholds set by organizations like OSHA, EPA, NIOSH, or ACGIH. CO meters are typically more sensitive than UL2034-compliant home CO detectors. While objective comparisons can be challenging without USA NIST Calibration reference gas, even some cheap options may be suitable for certain applications. However, it is crucial to take carbon monoxide seriously, as it is a deadly killer. Investing in a reliable CO meter is a critical step in ensuring the safety of yourself and others.
About The AuthorDr. Kos Galatsis ("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 enjoying the outdoors. Read more about Forensics Detectors here. Email: drkoz@forensicsdetectors.com |