Carbon monoxide (CO) is a dangerous gas that you can’t see, smell, or taste. But does it rise or fall? Whether it’s from gas appliances, stoves, or even car exhaust, CO can build up without warning. In this guide, we’ll explain how CO behaves, why it’s so dangerous, and how you can protect yourself and your family from it. 

What Is Carbon Monoxide?

Carbon monoxide is a colorless, odorless, and tasteless gas. It forms when fuels like gas or wood burn incompletely. This gas burns with a violet flame and is slightly soluble in water. It has a specific gravity of 0.96716 and a boiling point of -190°C. Its solidification point is -207°C, with a specific volume of 13.8 cubic feet per pound at 70°F. CO is also an inorganic compound with an auto-ignition temperature of 1,128°F when liquid. 

When inhaled, carbon monoxide replaces the oxygen in your blood and leads to poisoning. This can happen quickly if CO levels rise fast or slowly over time. So, always be cautious with fuel-burning appliances and use carbon monoxide detectors to stay safe.

Is Carbon Monoxide Dangerous?

Carbon monoxide is incredibly dangerous because of many reasons. For one, its molecules are so small they can travel through walls. It also mixes easily with the air inside your home. 

Since CO has no odor, color, or taste, it’s called the “silent killer.” 

Plus, dangerous concentrations can build up indoors without you even knowing until you start feeling sick. The symptoms of CO poisoning are also similar to the flu—headaches, dizziness, and nausea—so people often mistake them for something else and ignore the early signs.

The CDC (Center for Disease Control and Prevention) estimates that around 400 people die from unintentional CO exposure in the US each year. Infants, the elderly, and people with heart disease or breathing problems are also vulnerable. The same report states more than 100,000 people end up in emergency rooms due to CO exposure, and over 14,000 are hospitalized. This is why it’s so important to have carbon monoxide detectors in your home. Remember, CO poisoning can happen to anyone, so always be alert.

Symptoms of Carbon Monoxide Poisoning

Carbon monoxide poisoning is dangerous and hard to spot. Its symptoms often mimic common illnesses, making it easy to overlook. Stay safe by knowing the symptoms of carbon monoxide below:

• Headache: A common sign of CO poisoning. It can range from mild to intense.
• Weakness: You might feel unusually tired or weak, even if you haven't done anything physically demanding.
• Dizziness: A typical symptom is feeling lightheaded or like you're about to pass out.
• Nausea or vomiting: CO poisoning can upset your stomach, leading to nausea or vomiting. 
• Shortness of breath: You may feel like it’s hard to breathe, even when resting or not doing anything strenuous.
• Confusion: CO can affect your brain and make you feel disoriented or unable to think clearly.
• Blurred vision: You might notice your vision is blurry or harder to focus.
• Drowsiness: You could feel unusually sleepy or unable to stay awake.
• Loss of Muscle Control: CO poisoning can make it hard to move or control your body the way you usually do.
• Loss of Consciousness: Severe poisoning can cause you to faint or lose consciousness.

In worse cases, people might experience symptoms that affect the nervous system:

• Memory loss: You might have trouble remembering things, even ones that seem important.
• Personality changes: CO poisoning can also cause noticeable shifts in your actions or thoughts.
• Movement problems: People might also struggle with coordination or have trouble walking.

You should note that CO poisoning is especially risky for people who are asleep, drunk, or using drugs. They may not notice the symptoms until it's too late, and CO can cause serious brain damage or even death. If you or someone else shows signs of poisoning, get fresh air and call 911 immediately.

Does Carbon Monoxide Go Up or Down?

Carbon monoxide (CO) doesn’t go up or down like some gases. Its specific gravity is 0.9657. This is slightly lighter than regular air, with a specific gravity of 1.0. So, CO tends to mix evenly with the surrounding air instead of floating to the top or sinking to the bottom.

In particular, carbon monoxide will spread throughout the room and blend with the air. If there's a heat source or a malfunctioning appliance, the gas might be released closer to the ceiling at first. However, it won't stay there for long. The carbon monoxide disperses more evenly as the heated air cools and mixes with the room's air. This is why CO detectors are often placed at breathing height. Since we breathe in the air closest to us, putting detectors at that level helps catch CO regardless of where it is in the room.

It’s important to note that in specific situations (e.g., car exhaust or gas stoves), CO can build up in concentrated amounts near the source before it disperses. That’s why ventilate areas where such appliances are used. On the other hand, carbon monoxide will mix more easily with the air in outdoor areas or places with good ventilation.

Why You Need Carbon Monoxide Detectors

Carbon monoxide is a silent and invisible threat in our homes. Since it’s odorless, colorless, and tasteless, it’s impossible to sense it without a detector. Here are the top reasons why you need a carbon monoxide detector at home: 

1. Detects Dangerous CO Levels

Carbon monoxide detectors sense the carbon monoxide levels. When CO levels rise, the detector will trigger a loud alarm and warn you of the danger. These alarms are similar to smoke detectors but use different technologies to detect carbon monoxide. 

In particular, CO detectors use electrochemical or metal oxide sensors. These sensors pick up even small amounts of CO and trigger the alarm when the concentration reaches dangerous levels. Without this alert, you won’t know you’re breathing in harmful gas.

2. Protects Your Family’s Health

Carbon monoxide exposure can be harmful even in small amounts. Plus, long-term exposure can cause serious health issues. It can damage vital organs like the brain, liver, and lungs. CO is also especially dangerous for children, the elderly, or people with pre-existing health conditions. In addition, symptoms of CO poisoning are easy to confuse with the flu—headaches, dizziness, nausea, and confusion—so having a detector in place can help catch these issues early.

There are many potential sources of CO in your home, including malfunctioning appliances like water heaters, furnaces, or stoves. CO can also build up from car exhaust or small engine fumes entering your home through open windows or vents. For example, leaving a car running in a garage or near an open window can allow CO to seep into the house, creating a dangerous situation. A CO detector can alert you to dangerous levels, even when you don’t notice the problem.

3. Peace of Mind

Knowing your home is equipped with a working carbon monoxide detector gives you peace of mind. You won’t have to worry about the invisible threat of carbon monoxide sneaking up on you. It’s an investment for the safety of your family. Many modern detectors are sensitive enough to catch even very low levels of CO, which lets you act before the problem gets worse. 

4. Saves Lives

Carbon monoxide detectors save lives by letting you know when CO levels become dangerous. Since CO has no smell or color, it’s impossible to know it’s there without a detector. You know it’s time to get out fast when the alarm goes off. The quicker you act, the less risk of serious harm like unconsciousness or organ damage. A CO detector gives you that critical heads-up to prevent death. 

Sources of Carbon Monoxide

Carbon monoxide comes from many sources, especially when fuel is burned. By being aware of these sources, you make sure your home stays safe from the silent killer. Here are the common sources of carbon monoxide: 

• Gas Appliances

Stoves, ovens, and water heaters that burn gas can release CO if not working. Carbon monoxide is produced when the combustion process is incomplete. So, you should regularly check these appliances.

• Fuel-Burning Heaters

Wood stoves, fireplaces, and kerosene heaters can release CO if there’s insufficient ventilation or the chimney gets clogged. Always keep your chimneys clean and make sure the area is well-ventilated.

• Automobiles

Running a car in an attached garage can let CO build up quickly, even with the door open. Vehicles are a major cause of CO poisoning, so never leave your car running in your garage, even for a few minutes.

• Generators

Using a gas-powered generator indoors or too close to a house can cause CO buildup. Always run your generators outdoors and away from windows and vents to avoid CO poisoning.

• Clothes Dryers

Gas-powered dryers can produce carbon monoxide if they’re not venting properly. Make sure your dryer is correctly installed and its vent cleared to prevent CO buildup.

• Boilers and Central Heating Systems

They can release carbon monoxide if there’s a problem with the combustion process or if they’re poorly maintained. 

• Camping Stoves

Using a camping stove indoors or in a poorly ventilated area can produce CO. Always use these stoves outdoors or in open spaces.

• Grills

Grilling with charcoal or gas in an enclosed space is dangerous. Always grill in a well-ventilated space.

• Fireplaces

Wood-burning or gas fireplaces can produce carbon monoxide if they’re not burning properly or if the ventilation’s blocked. Regular chimney inspections help prevent this.

• Tobacco Smoke

Smoking tobacco releases small amounts of carbon monoxide. It’s not usually enough to cause poisoning, but you should be aware of the risks, especially in poorly ventilated areas.

• Open Fires

Any open flame, like a campfire or fire pit, can produce carbon monoxide. Always keep the fire in an open area where the gas can escape. 

Where Is the Best Place to Put a CO Detector?

Having carbon monoxide detectors is just as important as knowing where to place them. Here are the best spots to install them at: 

Near Sleeping Areas

Install carbon monoxide detectors near sleeping areas. This is where you're most likely to be affected by CO, especially if you're asleep and can’t notice it. Install detectors inside or just outside each bedroom to make sure you’ll hear the alarm if anything goes wrong.

On Every Floor

At the very least, you should have a CO detector on every floor of your home, including the basement. Carbon monoxide can spread evenly throughout your house, so placing detectors on each floor increases the chances of early detection. If you have multiple rooms or levels, consider adding more detectors to cover those areas.

At Eye Level

While CO is slightly lighter than air, it mixes evenly with the surrounding air. Place your detectors at eye level for better accuracy. Doing this also lets you easily read the display on most detectors. Doing this lets you quickly check carbon monoxide levels without looking up at the ceiling.

In Hallways Leading to Bedrooms

Does your house have long hallways leading to bedrooms? If yes, place one detector in each hallway. Doing this helps monitor the areas where you and your family sleep. It also makes sure you're alerted quickly if CO is detected.

In the Basement and Garage

Basements and garages are common spots for CO buildup, especially with appliances like water heaters, furnaces, and cars. Install a CO detector in the basement and garage to monitor these areas. Carbon monoxide can accumulate in these areas quickly, especially with poor ventilation. 

Places to Avoid

Putting CO detectors in some areas can lead to false alarms or reduce their effectiveness. Here are the spots to avoid:

Near Combustion Sources

Avoid placing detectors close to sources of combustion. These include gas stoves, fireplaces, or water heaters. These appliances emit small amounts of CO during normal use, which could trigger false alarms.

In Poorly Ventilated Areas

Avoid putting CO detectors in isolated corners or places with poor airflow. These areas can prevent the detector from accurately sensing CO, making it less effective.

How Does Carbon Monoxide Travel in a House?

Carbon monoxide moves easily through walls, ceilings, and even small openings. This is why you could have CO in one room and not notice it until it reaches where you are. Carbon monoxide can also spread through ducts, air vents, or cracks in windows and doors, so seal them properly.

In addition, carbon monoxide can enter your home through ventilation systems or open windows if produced from an appliance or running car. That’s why it's important to never run a car in an attached garage, even with the door open.

Proper ventilation in your home can help carbon monoxide dissipate. But if there’s a malfunction or poor airflow, CO can build up without you realizing it. This is why having CO detectors in the right places is so important.

Will Opening a Window Help With Carbon Monoxide?

Yes, opening windows help with carbon monoxide. However, it’s sometimes not enough.

Opening a window can help reduce carbon monoxide levels in your home, but it’s not enough. CO spreads evenly through the air, so opening a window helps by letting fresh air in and allowing the gas to escape. This can lower the concentration of CO in the room, especially if there’s some airflow.

However, opening a window might not be enough to get rid of high levels of CO, especially if the source is still active. If your carbon monoxide detector goes off, leave the house and call for help. Ventilating the space can help a little, but it’s not a fix for high levels of carbon monoxide. 

What to Do When Your Carbon Monoxide Detector Goes Off

1. Ventilate the Area

Open windows and doors to let fresh air in. This helps lower the CO levels inside while you take action.

2. Turn Off Fuel-Burning Appliances

Turn off any appliances that burn fuel, like your stove, furnace, or water heater. This can help stop the CO buildup.

3. Evacuate the House

Quickly get your family and pets and leave the house. Call the authorities once you're safe outside. Let them know your CO detector went off and follow their instructions. When emergency responders arrive, show them any possible sources of CO, like appliances or heating systems. They’ll handle the rest and check your home for danger.

4. Seek Medical Attention if Needed

If anyone shows signs of CO poisoning (headache, dizziness, nausea), get them medical help immediately. CO poisoning can be serious, so don't wait.

5. Stay Out Until It's Safe

Don’t go back inside until the authorities say it’s safe. Stay somewhere else, like a hotel, especially if you have young kids or pets.

Conclusion

Understanding how carbon monoxide behaves helps you and your loved ones stay safe. While CO doesn't exactly rise or fall, it mixes evenly with air, making it harder to detect without the right tools. This is where a carbon monoxide detector comes in. 

However, protecting your home goes beyond just CO detectors. You also need fire prevention tools like smoke alarms, fire extinguishers, fire blankets, and fire sprays. These tools protect you from invisible threats, keeping you and your family safe.