Low Level Carbon Monoxide Detector (2024 update)

Carbon Monoxide Detector, Low Level CO Detector -

Low Level Carbon Monoxide Detector (2024 update)

Gas detection is a matter of life and death when it comes to carbon monoxide (CO), a lethal gas known as the "silent killer" due to its colorless, odorless, and tasteless nature. The importance of CO detection has led many states and cities to mandate the use of carbon monoxide alarms and detectors in homes. However, the necessity of gas detection extends beyond residential settings. When traveling, RV driving, or boating, having a reliable CO detector is equally crucial. These portable gas detection devices ensure that you and your loved ones remain protected from the deadly effects of carbon monoxide, regardless of your location. Investing in a quality CO detector and maintaining proper gas detection practices can make the difference between a safe journey and a tragic outcome.



  • Carbon monoxide detectors help protect from unintentional CO exposure.
  • CO alarms are affordable.
  • A plethora of carbon monoxide alarms exist for a variety of applications.
  • Carbon monoxide symptoms may be seen as "flu like"
  • It can be difficult to track down the carbon monoxide source.
  • Public awareness of carbon monoxide poisoning is still limited.
  • Carbon monoxide is a silent killer.

What Is Carbon Monoxide?

Carbon monoxide (CO) is a toxic gas. OSHA emphasizes that carbon monoxide is a poisonous, colorless, odorless, and tasteless gas - making it very elusive. Although CO has no smell, it is often mixed with other gases that do have an odor (i.e. exhaust gas).

When carbon monoxide is inhaled, your body replaces the oxygen in your red blood cells with carbon monoxide. This leads to asphyxiation, serious tissue damage, brain damage, and even death.

Is Carbon Monoxide Dangerous? 

According to the CDC, about 430 people die in the USA each year from accidental CO poisoning. Approximately 50,000 Americans visit the emergency room yearly due to unintentional CO poisoning. 

What Are the Symptoms of Carbon Monoxide Exposure?

CO is particularly dangerous when sleeping, often leading to carbon monoxide poisoning at night. People may have irreversible brain damage or even die before anyone realizes there is a problem, hence the title of silent killer. The Mayo Clinic describes the typical signs of carbon monoxide exposure and poisoning as:

  • Headache
  • Weakness
  • Dizziness
  • Nausea or vomiting
  • Shortness of breath
  • Confusion
  • Loss of consciousness

What Produces Carbon Monoxide?

The Cleveland Clinic highlights that CO is found in exhaust and flue gases produced during any form of combustion. Common examples and problem situations include:

  • Car and truck engines (leaving a car running in the garage).
  • Small gasoline engines (portable generators running in or close to the home).
  • Gas stoves and gas lanterns (using your home oven for heating).
  • Heating systems, including home furnaces (cracked heat exchangers and backdrafting effects).
  • Burning charcoal, kerosene, propane, or wood (indoor BBQ).
  • Tools with small engines such as saws (use in confined spaces is deadly).

What Should I Do If I Suspect Carbon Monoxide Is in My Home?

If you are experiencing carbon monoxide poisoning symptoms, immediately seek fresh outdoor air. Evacuate from your home and call 911.

If someone is unconscious or unable to leave the building, open nearby doors and windows, but do so without causing yourself harm. Don't forget, CO is odorless and tasteless so it is important to evacuate quickly. First responders have CO meters and can enter indoor spaces safely.

The fire department may be able to find the source of elevated carbon monoxide levels and provide guidance on the problem area. If it is a defective appliance, ensure it is inspected by a qualified professional, have the appliance repaired, or  replaced.

Be vigilant if you are living in a building with other occupants as the CO may be coming from your neighbor. CO movement is elusive due to turbulence, micro plume, and draft effects that are hard to predict. The carbon monoxide source may be in location but the gas can travel to a totally different area.

fire department carbon monoxide

What If I Inhaled CO Gas?

If you think you're suffering from CO exposure, breathe some fresh air as soon as you can. Move to an outdoor environment. 

Call the fire department or paramedic to be on the safe side. Seeking medical help is important because you may require oxygen. You might also need tests so medical professionals gain a better insight into the severity of your exposure. Based on the diagnosis, you may require hyperbaric therapy.

Tips to Prevent a Carbon Monoxide Leak? 

There are many things you can do to remain safe from carbon monoxide throughout the year. First and foremost, be aware of all combustion appliances that exist in and around your home. You would be surprised by how many home owners and tenants do not know where their gas burning appliances are located. This awareness is imperative for your safety.

  • Make it a habitual task to visually inspect your gas burning appliance flue stacks to make sure everything is in order.
  • If you are living in a shared building, ask your landlord for the location of all gas burning appliances - Pool heaters are the most dangerous as they have a massive BTU rating and emit large volumes of exhaust.
  • Have a professional install your appliances such as heating equipment, water heaters, or central heating equipment. 
  • Keep vents and exhausts clear of blockages. Again, understand your venting situation, learn what is intake and what is exhaust.
  • Change your CO detector batteries once per year.
  • Do not use an oven or range stovetop to provide heat to your home.
  • Reduce use of space heaters and turn them off when sleeping. Ensure good airflow and ventilation in your indoor space.
  • Install carbon monoxide detectors on each floor of your home, within 15 feet of each sleeping area.
  • CO detectors have a limited life span; check the manufacturer's instructions for information on replacement. The typical lifespan of a CO detector ranges from 2 to 10 years.
  • Never leave your car running your garage. If you are forgetful or have dementia, refrain from parking in your garage.
  • Never use portable generators inside homes or garages, even if doors and windows are open. Keep the generator exhaust position downwind and away from your home.
  • Never BBQ in the house or garage. Propane grills are also dangerous for heating or cooking. 

Do I Need a CO Detector?

Yes! They are cheap and there are no excuses!

Do yourself and your family a favor. Be safe and be smart.

It actually may be mandatory that you have one in your home by your local city code and/or state legislation. The majority of US states have now mandated CO detectors in homes. 

Where Should a Low Level Carbon Monoxide Detector Be Placed?

CO alarms should be mounted in or near bedrooms and living areas. It is recommended that you install at least one CO alarm on each level of your home. 

For the upmost protection, we recommend installing a CO detector in each bedroom (since most CO related deaths occur when sleeping), living area, garage, or basement (for very early warning).

When choosing your installation locations, make sure you can hear the alarm from all sleeping areas. If you install only one CO alarm in your home, install it near bedrooms. When wall mounting, keep it out of the reach of children, pets, or accidental bumps.

Placing the alarm at eye level is recommended as it allows for optimum daily monitoring of the digital display.

It is also a good idea to think about the places you should avoid installing CO detectors, such as: 

  • Areas where the temperature is colder than 40°F (4.4°C) or hotter than 100°F (37.8°C), it will stress the CO sensor and may reduce its useful life.
  • Within 5 feet of heating or cooking appliances.
  • Near vents, flues, chimneys, or any forced/unforced air ventilation openings.
  • Near ceiling fans, doors, windows, or areas directly exposed to the weather. Prevent external air, water, or rain from reaching the alarm.
  • In dead air spaces, such as peaks of vaulted ceilings or gabled roofs, where CO may not reach the sensor in time to provide early warning.
  • On a switched or dimmer-controlled outlet.
  • Near deep-cell large batteries. Large batteries have gas emissions that can cause the alarm to perform at less than optimum performance.
  • Near items that will obstruct the vents located on the alarm. Do not place the alarm where drapes, furniture, or other objects block the flow of air to the vents.

The Low Level Carbon Monoxide Detector Is Beeping, What Does It Mean?

Your CO detector will beep primarily for two main reasons:

  • It has detected carbon monoxide and will alarm with continuous beeps, i.e. 4 or 5 beeps in a continuous fashion.
  • The battery is low and will "chirp" about once per minute to alert occupants that batteries need replacement.

Please read your CO alarm manual as the beeping sequence and their meaning may vary by manufacturer and model.

Should I Take My Low Level Carbon Monoxide Detector Alarm Seriously?

Absolutely, take action. Evacuate from your indoor surroundings and call 911.

To illustrate the seriousness, consider the following example. In 2019, Illinois fire departments responded to 23,000 calls about CO and were able to determine a leak at 11,000 of those locations - nearly 50%.

How Do I Take Care of My Low Level Carbon Monoxide Detector?

Your CO detector doesn't need much special care. Just make sure to press the TEST button weekly and change the batteries yearly. Make sure the vented slots are not clogged with any dust and follow the manufacturer's care booklet. Always use fresh alkaline or lithium batteries. Again, check to make sure it is operational by checking the LED lights, the battery bar life, and pressing the TEST button. Typical maintenance steps include:

  • Test the alarm weekly by pressing the TEST button.
  • Check grilled vent slots to ensure no blockage.
  • Clean regularly to prevent dust build up.
  • This can be done using a vacuum cleaner with the brush attachment once per month. Clean gently around the front grilled vent slots.
  • Never use cleaning solutions on your alarm.
  • Do not paint the alarm.
  • Do not tamper with any of component as this may interfere with proper fuctioning and lead to risky situations.

co detect and alarm

Which CO Levels Are Important? 

No standards for CO have been agreed upon for indoor air. This is the reason why various agencies, departments, and organizations recommend different exposure levels. These differences have caused a lot of confusion among the public.

To help, we have put a table together here to summarize important CO levels:





9 ppm average over 8 hours



9 ppm average over 8 hours



9 ppm average over 8 hours



35 ppm average over 10 hours

200 ppm ceiling value


50 ppm average over 8 hours



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 to15 minutes)
USA carbon monoxide detectors

CO Detector Alarming Protocol
EN 50291:2001 (Europe)

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

Europe carbon monoxide detectors

Forensics Low Level Carbon Monoxide Detector

> 25 ppm (1 minute)

Forensics Detectors Low Level Detectors

What Is a UL2034 CO Alarm? When Does It Alarm?

Nearly all carbon monoxide detectors that are mandated by city, county, or state jurisdictions require the device to comply with UL2034 standards. Nearly any CO detector you purchase from Home Depot, Lowes, Costco, and other large retail stores are UL2034 compliant.

The UL2034 requires CO detectors to alarms at specific times and concentrations. For a typical UL2034 carbon monoxide detector, the alarm requirements are as follows: 

  • > 70 ppm for 60 to 240 minutes
  • > 200 ppm for 10 to 50 minutes
  • > 400 ppm for 4 to15 minutes

However, when you purchase a UL2034 compliant CO detector, it will include something similar to the following text: 

Warning: This product is intended for use in ordinary indoor locations of family living units. It is not designed to measure compliance with Occupational Safety and Health Administration (OSHA) commercial or industrial standards. Individuals with medical problems may consider using warning devices which provide audible and visual warnings for carbon monoxide concentrations under 30 ppm.

co detector from costco

What Is a Low Level Carbon Monoxide Detector?

A low level carbon monoxide detector is a specially designed monitor to provide added protection for older adults, elderly, pregnant women, young children, and those with medical conditions. These groups may be more vulnerable to the adverse health effects of low levels of CO exposure.

As we showed previously, UL2034 CO detectors are not designed to measure levels in compliance with OSHA standards. To have that extra layer of protection from carbon monoxide exposure and symptoms, a low level CO detector may be warranted.

For example, the FORENSICS low level CO detector triggers an audible alarm when CO is detected > 25 ppm. Such low level CO alarming is closer to various government CO gas exposure limits than traditional detectors following UL2034 (70 ppm from 60 - 240 minutes).

However, a low level CO detector IS NOT a replacement for a UL2034 carbon monoxide detector, which is mandatory per most local codes and state legislation.

Is Carbon Monoxide Gas Lighter or Heavier Than Air?

Carbon monoxide is approximately 3% lighter than gaseous air.

Although factors such as molecular weight and temperature affect the rate of diffusion, they do not influence the ultimate distribution of carbon monoxide gas. Therefore, placement of your CO detector is not affected. This has been shown by experimental studies by Professor Hampson.

Are Carbon Monoxide Detectors Reliable?

Yes they are mostly reliable and there is no excuse to NOT purchase a CO detector.

In a 2011 study by Ohio University, 30 carbon monoxide detectors were tested. More than half of these in-use analyzers failed to function properly, alarming too early or too late. 40% of detectors failed to alarm in hazardous concentrations, despite outward indications that they were operating as intended. 

Should I Bring a Carbon Monoxide Detector When Traveling to a Hotel, Boat, or Plane?

Yes you should bring a working carbon monoxide detector or a travel CO detector. Some hotels may have them installed while others may not. Even when they are installed, these detectors may be expired or have dead batteries. Always travel with a CO detector to be on the safe side.

Should I Have a Carbon Monoxide Detector When I Drive a Car?

Yes you should. Forensics Detectors makes a vehicle CO detector. Unfortunately there are many examples of leaked carbon monoxide into vehicle cabins. For example:

  • Ford Explorer was reported to leak carbon monoxide in the cabin and highlighted by the Center for Auto Safety.
  • Polluted outdoor air may enter your cabin as shown here by Dr. Koz.
  • Your vehicle may allow exhaust gas and carbon monoxide to enter the cabin via panel cracks, poor seals, and holes, see here.

vehicle CO detector

Who are the sensitive groups that are more vulnerable to the adverse health effects of carbon monoxide?

Sensitive groups include seniors, pregnant women, young children, and individuals with medical conditions. Seniors are more prone to developing brain damage, while those with breathing problems or anemia are more likely to get sick when exposed to carbon monoxide. Unborn babies are especially vulnerable, as CO exposure during pregnancy can cause severe damage and even fetal death.

Should homeowners consider purchasing low-level carbon monoxide detectors?

Homeowners should consider purchasing low-level carbon monoxide detectors for added protection. Standard detectors may give a false sense of security, as they only alarm when there are high and potentially deadly amounts of carbon monoxide in the house. Low-level detectors provide faster alarming and can help prevent health issues caused by continuous low-level exposure.

Are standard carbon monoxide detectors effective for detecting low gas levels?

Standard carbon monoxide detectors may not be effective in detecting low gas levels. They are typically set to trigger at higher concentrations, usually 70 ppm after 60 minutes, and may not provide adequate protection against prolonged exposure to low levels of carbon monoxide.

Does a Low Level Detectors provide extra safety?

Having a low level carbon monoxide detector provides peace of mind for you and your family by ensuring early detection and prevention of CO poisoning.

  • Early Detection: A detector alerts you to low levels of CO, allowing you to address any potential issues before they become dangerous.
  • Increased Safety: By continuously monitoring CO levels, a detector helps prevent poisoning and protects your family from harm.
  • Peace of Mind: Knowing that you have a reliable detector in place brings a sense of security and reassurance to you and your loved ones.

How Does a Low Level Carbon Monoxide Detector Work?

Low level carbon monoxide detectors, like their counterparts, work by using sensors to measure the concentration of carbon monoxide in the surrounding air. These detectors make use of electrochemical sensors, which are specifically designed to detect and convert carbon monoxide into an electrical signal. This process enables the detector to accurately determine the presence of carbon monoxide at low levels. Once the concentration of carbon monoxide reaches a specific level, the detector promptly alerts the occupants through visual and audible alarms. These alarms serve as a warning signal, prompting individuals to take immediate action to ensure their safety. It is crucial to regularly test and calibrate the detector as per the manufacturer's instructions to guarantee its proper functioning and effectiveness.


Gas detection is crucial in protecting your home and loved ones from the silent killer, carbon monoxide (CO). Investing in a CO detector and properly installing it in your home is a smart move. Thoroughly read the manual and familiarize yourself with the various combustion appliances in your home. Conduct visual inspections to ensure all appliances are venting correctly, and exercise caution when using portable generators or fossil fuel-powered equipment. Maintain your CO detector and consider upgrading to a low-level CO detector for early warning and added protection. These devices detect CO at lower concentrations (25ppm alarm trigger), providing an extra layer of safety against the dangers of carbon monoxide poisoning, which can cause headaches, dizziness, nausea, confusion, and even death. By prioritizing gas detection and following proper placement and maintenance guidelines, you can significantly reduce the risk of CO poisoning and ensure the well-being of your family.

    References and Further Reading

    The World Health Organization (WHO)

    WHO is a specialized agency of the United Nations that is concerned with international public health. To protect the public from chemical exposure, WHO has published guidelines for toxic chemicals in indoor air. The guideline for carbon monoxide exposure is 9 ppm at a time weighted average over an 8 hour period.

    (Reference: WHO. (2010). "WHO guidelines for indoor air quality: selected pollutants” ISBN 978 92 890 0213 http://www.euro.who.int/__data/assets/pdf_file/0009/128169/e94535.pdf)

    The United States Environmental Protection Agency (EPA)

    The EPA is a federal agency concerned with air quality standards and has set maximum standards for pollutants considered harmful to public health. The Table of Historical Carbon Monoxide National Ambient Air Quality Standards establishes a concentration of 9 ppm at a time weighted average over an 8 hour period since 1971.

    (Reference: https://www.epa.gov/co-pollution/table-historical-carbon-monoxide-co-national-ambient-air-quality-standards-naaqs)

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

    ASHRAE has created maximum standards for pollutants considered harmful to public health, and also establishes a concentration of 9 ppm at a time weighted average over an 8 hour period.

    (Reference: https://www.ashrae.org/File%20Library/Technical%20Resources/Standards%20and%20Guidelines/Standards%20Addenda/62-2001/62-2001_Addendum-ad.pdf)

    The National Institute for Occupational Safety and Health (NIOSH)

    NIOSH is a federal agency under the Department of Health and Human Services that published a recommended daily exposure limit of no more than 35 ppm at a 10 hour time weighted average and a ceiling value of 200 pm, where the ceiling value should not be exceeded at any time

    (Reference: http://www.cdc.gov/niosh/npg/npgd0105.html)

    The Occupational Health and Safety Administration (OSHA) 

    OSHA is a federal agency under the Department of Labor that develops and enforces federal standards for health and safety in the workplace. They recommend a permissible exposure limit (PEL) of carbon monoxide to no more than 50 ppm at a time weighted average over an 8 hour work day. 

    (Reference: https://www.osha.gov/OshDoc/data_General_Facts/carbonmonoxide-factsheet.pdf)

    The American Conference of Governmental Industrial Hygienists (ACGIH) 

    ACGIH has assigned a carbon monoxide threshold limit value (TLV) of 25 ppm (29 mg/m(3)) as a TWA for an 8-hour workday and 40-hour work week.

    (Reference: [ACGIH 1994, p. 15] )

    About The Author

    Dr. 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.

    gas detector expert

    Everyday 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 Detections here.

    Email:  drkoz@forensicsdetectors.com
    Phone: +1 424-341-3886