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Where to Install Carbon Monoxide Detectors (High or Low?)

If you’re concerned about keeping your family safe, you might be asking yourself:

Where should I install carbon monoxide detectors in my home?

To ensure complete coverage, the most important places to put carbon monoxide detectors are near all sleeping areas, on every level of your home, near attached garages, between 25 and 15 feet from fuel-burning appliances and fireplaces, and anywhere else the detector manufacturer recommends.

To avoid false alarms, do not install carbon monoxide detectors within 15 feet of fuel-burning appliances, near bathrooms, in direct sunlight, behind furniture, or in the direct path of flowing air such as vents, fans, and open windows.

There’s an ongoing debate over whether you should place carbon monoxide detectors low on the wall close to the floor or high on the wall close to the ceiling. In short, the placement height doesn’t matter because carbon monoxide spreads evenly throughout a room. This isn’t my opinion; experts arrived at this conclusion by conducting a scientific study. Since this is such a hot topic, I dive deeper into it later in this article (skip ahead to that section).

Now that you know the basics about where to put carbon monoxide detectors in your home, let’s get into more detail so you can ensure your family stays safe for years to come.

Click the links below to go straight to a section.

Carbon Monoxide Detector Placement: High or Low?

There’s a consensus among experts about which rooms to install carbon monoxide detectors; however, there’s debate over the ideal placement height. The short answer is that the placement height of carbon monoxide detectors does not matter because carbon monoxide spreads evenly (ceiling, middle, floor) throughout the air in a home.

Some say detectors are more effective closer to the ground because they believe carbon monoxide is heavier than air; therefore, it concentrates low to the floor. Other experts recommend installing detectors high on the wall or on the ceiling because carbon monoxide is lighter than air and rises like smoke.

The truth is, the placement height of carbon monoxide detectors does not matter, and this has been proved by a scientific study.

In 2012, Elsevier, an academic research and publishing company, conducted a study to determine if the placement height of carbon monoxide detectors matter.

Dr. Neil B. Hampson MD, a pulmonologist in Seattle, Washington, who specializes in the treatment of carbon monoxide poisoning among other respiratory illnesses, led this study. 

To conduct the study, Hampson and his researchers constructed an 8-foot tall airtight chamber and placed carbon monoxide detectors at the top, middle, and bottom of the chamber. They infused carbon monoxide into the chamber during separate trials at each height level.

The results of the trial showed that carbon monoxide did not level out at the top, middle, or bottom but spread evenly throughout the chamber over time. They learned in the study that carbon monoxide is, in fact, lighter than air. However, the difference is so minimal that it has no impact on the concentration of the gas.

Some carbon monoxide detectors need to be plugged into an outlet, which is why they are placed lower to the ground. Other detectors feature a digital display that monitors carbon monoxide levels, and, in those cases, eye level is the ideal placement height.

If the detector that you buy provides specific instructions on placement height, follow those instructions.

Although the placement height of carbon monoxide detectors does not matter, what matters is that you have them throughout your home. Remember, near every bedroom or sleeping area, on every level, near carbon monoxide producing appliances and systems, and the more detectors, the better.

Where to Put Carbon Monoxide Detectors

Near all sleeping areas.
The most important place to install carbon monoxide detectors in your house is near every bedroom and sleeping area. Carbon monoxide poisoning is especially dangerous at night because you may not feel any symptoms in your sleep, and deep sleepers may not hear the alarm. The hallway that leads to each bedroom is a perfect place to install a detector.

On every floor.
Install detectors on every floor of your home, including the basement. Some floors could be more saturated with carbon monoxide than others, so it’s imperative to make sure each level of your home is covered.

Near an attached garage.
Car engines produce carbon monoxide, which can make its way into your house. This is the reason you should never turn on your car while the garage doors are closed. Due to this risk, install a carbon monoxide detector close to where your house and garage are connected.

Near fuel-burning appliances like gas furnaces and stoves.
All fuel-burning appliances produce carbon monoxide. According to Vivint, the most common carbon monoxide poisoning sources are gas space heaters, furnaces, chimneys, gas stoves, gas generators, and automobile exhaust. If you have any of these appliances in your house, it’s wise to put carbon monoxide detectors within 20 feet but no closer than 15 feet. Placing detectors too close to these areas will likely trigger false alarms.  

Where the manufacturer recommends.
Every carbon monoxide detector is slightly different. Read the manufacturer’s manual to see if they have specific placement instructions and, if so, follow those instructions.

Where to Avoid Putting Carbon Monoxide Detectors

As important as it is to ensure you have enough detectors in the right spots, it’s also important to avoid installing them in places that will trigger false alarms.

Within 15 feet of fuel-burning appliances.
Avoid putting carbon monoxide detectors within 15 feet of your gas-powered stove, gas-burning furnace, and fireplace. As I mentioned previously, those areas are where safe levels of carbon monoxide are produced. Putting detectors in close proximity to your furnace will trigger false alarms when there is no danger.

Bathrooms, direct sunlight, and in the path of flowing air.
Avoid putting detectors near bathrooms, sunrooms, or in the direct path of blowing air near vents, fans, or open windows. Most carbon monoxide detectors are designed to work within specific humidity and temperature levels, and the volatility of those areas will likely trigger false alarms.

Behind curtains of furniture.
Make sure your detectors are not behind curtains or furniture. Any obstruction like that could prevent the gas from reaching the sensors.

In reach of small children.
Lastly, avoid putting detectors in the reach of small children. Most detectors have a test button right in the middle that kids love to press, which will set off the alarm. Not fun.

What Is Carbon Monoxide?

Carbon monoxide is a colorless, odorless, tasteless, and toxic gas that is produced by burning fuels like gas, petrol, diesel, wood, propane, and charcoal.

Why Is Carbon Monoxide Dangerous?

According to the United States Department of Occupational Safety and Health Administration (OSHA), “Carbon monoxide is harmful when breathed because it displaces oxygen in the blood and deprives the heart, brain, and other vital organs of oxygen. Large amounts of CO can overcome you in minutes without warning—causing you to lose consciousness and suffocate.

Since carbon monoxide is colorless, odorless, and tasteless, there is no way to detect its presence without a carbon monoxide detector. When an appliance leaks, fails, or when rooms are poorly ventilated, dangerous levels of carbon monoxide can saturate your home and cause severe illness and death.

It’s extremely important to have proper ventilation and conduct regular maintenance on all appliances, especially in today’s world, where homes are built airtight with heavy insulation.

What Are the Symptoms of Carbon Monoxide Poisoning?

According to the Mayo Clinic, the symptoms of carbon monoxide poisoning are dull headaches, weakness, dizziness, nausea, vomiting, shortness of breath, confusion, blurred vision, and loss of consciousness.

For more information on the causes, symptoms, diagnosis, and treatment of carbon monoxide poisoning, visit MayoClinic.org.

Carbon Monoxide Detector vs. Monitor: What Is the Difference?

When it comes to protecting yourself and your family from dangerous levels of carbon monoxide, you have two options, carbon monoxide detectors or monitors. So what is the difference?

Carbon monoxide detectors, also known as alarms, work just like a smoke alarm. When they detect dangerous levels of carbon monoxide in the air, they set off an alarm to warn you. These are the most common carbon monoxide devices, and, in most situations, these work perfectly fine.

Carbon monoxide monitors, as their name suggests, actively monitor the levels of carbon monoxide in the air. They typically feature a digital display that provides a real-time readout. Like detectors, monitors will also sound a loud alarm when carbon monoxide rises above the safe zone.

Even if carbon monoxide levels are not at a dangerous level, with a monitor, you’ll be able to see when they rise above normal levels and can proactively investigate any issues with appliances or ventilation.

If you have young children or live with senior adults, I’d recommend installing at least one carbon monoxide monitor in your house. Children and the elderly are more susceptible to poisoning even when carbon monoxide levels are not dangerous enough to set off the alarm. Only monitors will provide that level of insight. The only downside is that they are more expensive than simple detectors.

What Are the Best Carbon Monoxide Detectors and Monitors?

There are dozens of carbon monoxide detectors and monitors on the market. These options all have great reviews and are best sellers on Amazon.

  • First Alert CO605 Plug-In Carbon Monoxide Detector with Battery Backup (link to Amazon)
  • Kidde KN-COB-B-LPM Carbon Monoxide Alarm (link to Amazon)
  • Kidde Battery-Operated Carbon Monoxide Alarm with Digital Display (link to Amazon)
  • Leeo Smart Alert Smoke/CO Remote Alarm Monitor for iOS and Android (link to Amazon)

Are Carbon Monoxide Detectors Required by Law?

Most states require residential properties to have at least one carbon monoxide detector. According to the NCSL (National Conference of State Legislatures), residential carbon monoxide detectors are required by law in the following 38 states:

  • Alabama
  • Alaska
  • California
  • Colorado
  • Connecticut
  • District of Columbia
  • Florida
  • Georgia
  • Idaho
  • Illinois
  • Iowa
  • Kentucky
  • Louisiana
  • Maine
  • Maryland
  • Massachusetts
  • Michigan
  • Minnesota
  • Nebraska
  • New Hampshire
  • New Jersey
  • New Mexico
  • New York
  • North Carolina
  • North Dakota
  • Oklahoma
  • Oregon
  • Pennsylvania
  • Rhode Island
  • South Carolina
  • Tennessee
  • Utah
  • Vermont
  • Virginia
  • Washington
  • West Virginia
  • Wisconsin
  • Wyoming

Are you looking for ways to make your home safer? Check out these recent articles:

Andrew Palermo Founder of Prudent Reviews

Andrew Palermo - About the Author

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4 thoughts on “Where to Install Carbon Monoxide Detectors (High or Low?)”

  1. The reference to a research study by Elsevier needs a little work. It addresses the concern by Keven, above.
    The research study was published in Journal of Emergency Medicine. Elsevier is a publishing company which pubishes many professional and scientific journals.

    So rework that paragraph for clarity of the reference and what it said.
    They were obviously doing the research to answer the question of where to put CO detector due to conflicting recommendations.

    By the way the primary author on that study was a physician who is associted with a hyperbaric medicine unit. This is where patients with CO poisining get sent for lifesaving treatment. Therefore the author’s interest in validating recommendations for CO monitor detector placement.

    I am going out now to get another one for the basement.

    • Thanks for the comment, William.

      I added in more context around the study to make it more clear.

      I appreciate you stopping by the site!

  2. In a home the earliest detection would be at the ceiling. Pure carbon monoxide isn’t itself released. It comes from the products of incomplete combustion (which is heat) and hot air rises, then by definition CO is lighter than air. MW=28 of CO and air is 29, vapor density 0.97 of CO and air is 1.0. Just my 2cents


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