Carbon monoxide is called the silent killer for many reasons. But the good news is you can prevent it from poisoning you and your loved ones with the right detectors in place. The question is: how many carbon monoxide detectors do you need, and where should you put them?

The answer depends on many factors, but you can protect your family from this invisible, odorless gas with a few key steps. In this guide, we’ll talk about how many carbon monoxide detectors you need and where to put them. 

Do You Need Carbon Monoxide Detectors?

Yes, you need carbon monoxide detectors in your home. These detectors are essential for protecting you and your family from the dangers of carbon monoxide (CO). Carbon monoxide is a colorless, odorless, and tasteless gas. It’s produced when fossil fuels like natural gas don’t completely burn in appliances like furnaces, stoves, and water heaters.

The risk of CO poisoning is real. According to the CDC (Center for Disease Control and Prevention), about 400 people die from unintentional CO exposure not linked to fires in the US each year. The same report states more than 100,000 people end up in emergency rooms because of CO exposure, and over 14,000 are hospitalized. 

Carbon monoxide poisoning causes different symptoms depending on the level of exposure. Early signs include a mild headache, nausea, and shortness of breath. As exposure increases, symptoms can worsen to include chest pain, dizziness, weakness, and fainting. People may also experience loss of muscle coordination, mental confusion, severe headaches, an upset stomach, nausea, and vomiting. Carbon monoxide poisoning can also lead to unconsciousness or even death if not detected and treated quickly.

In addition, homes with fuel-burning appliances are more at risk. Many places, including Massachusetts, Illinois, and New York City, have laws requiring CO detectors in homes, especially in new buildings. Even if your area doesn’t have a law, it’s still a smart move to install carbon monoxide detectors in key areas.

How Many Carbon Monoxide Detectors Do You Need?

The number of carbon monoxide detectors you need depends on many factors, including how many floors and bedrooms your house has. Make an informed decision by considering the factors below: 

Number of Floors 

First of all, the number of carbon monoxide detectors you need depends on how many floors your home has. You should have at least one carbon monoxide detector on each floor. Carbon monoxide can easily spread throughout your home, and if you only have one detector for the whole house, you won’t be able to detect a leak on another floor. For example, if a leak occurs in the basement, a detector on the first floor might not pick it up. Having a detector on every floor helps detect the gas early, no matter where it originates.

Number of Bedrooms

Another important factor that determines how many carbon monoxide detectors you need is the number of bedrooms in your home. You should have at least one detector outside each bedroom. It’s because you’re most vulnerable to carbon monoxide poisoning while you’re asleep. 

Carbon monoxide poisoning can cause dizziness and headaches, which are easy to miss while you’re resting. A detector outside your bedroom will warn you before the gas affects you. Consider placing a detector near each one if you have multiple bedrooms on different floors.

Number of Gas-Powered Appliances

The number and type of gas-powered appliances also contribute to how many detectors you need. Carbon monoxide is produced when fossil fuels, like natural gas, are burned in appliances. These appliances include gas stoves, water heaters, furnaces, and dryers. 

Each is a potential source of carbon monoxide leaks, so you need a detector nearby. For example, place a detector near your utility room if you have a gas water heater there. Similarly, you need a carbon monoxide detector in your kitchen if you have a gas stove or oven. The more gas appliances you have, the more detectors you need. 

Home Layout and Size

Your house’s layout and size can also affect how many carbon monoxide detectors you need. 

For instance, you can protect a small house or apartment with a few detectors, especially if the bedrooms are close to each other and there aren’t many gas appliances. On the other hand, bigger houses need multiple detectors, especially if they have many floors and gas-powered appliances. In short, the bigger your house is, the more detectors you need.

Local Regulations

Lastly, local regulations affect how many carbon monoxide detectors you need. Some states have laws requiring CO detectors to be installed in homes and buildings, especially if they’re new. So, check your local building codes or regulations to make sure you’re meeting the legal requirements. While these laws vary, they can give a good starting point for determining how many detectors you need. 

Where Should a Carbon Monoxide Detector Be Placed?

Near Sleeping Areas

The most important place to put a carbon monoxide detector is near your bedroom. If you’re putting only one carbon monoxide detector, the Consumer Product Safety Commission (CPSC) recommends placing it near your sleeping area so it can wake you up if you’re asleep. 

The goal is for the alarm to sound before carbon monoxide levels become dangerous. CO poisoning can occur without clear signs, especially when you’re asleep or unconscious. But if you have the budget for it, experts recommend placing multiple carbon monoxide detectors all over your house. 

On Every Floor

The International Association of Fire Chiefs recommends placing a carbon monoxide detector on every floor of your home for added protection, including the basement. This makes sure that you’re warned no matter where a CO leak occurs. 

Carbon monoxide can travel quickly, so placing detectors on all levels covers your entire home. For instance, if a leak happens on the top floor, a detector on the ground floor won’t alert you in time. The same goes for people on other floors. 

Near (But Not Too Close) Gas Appliances

While carbon monoxide detectors should be placed near gas-powered appliances, they shouldn’t be too close. Don’t place carbon monoxide detectors directly above or beside these appliances. Gas appliances release small amounts of carbon monoxide, which may trigger false alarms if the detector is too near. 

A good rule of thumb is to place the detector within 15 feet of a gas stove, oven, furnace, or fireplace and within 10 feet of other appliances. Doing this lets the detector sense dangerous CO levels and prevents false alarms. Plus, follow manufacturer recommendations for each appliance because placement can vary depending on the appliance's size and type. 

Avoid Humid Areas

Don’t install carbon monoxide detectors in humid areas, such as bathrooms. The moisture can mess with the detector’s ability to work properly. Humid air can also cause false alarms. 

Stick to drier places where the air circulates better. Place the detector in a hallway or room close to the bedroom for easy access and better detection. 

Height Matters

Carbon monoxide is lighter than air. Because of this, experts recommend placing a carbon monoxide detector on the wall at eye level. Doing this also helps you read the carbon monoxide detector more easily than when it’s on the ceiling. 

Keep Away from Windows and Doors

Avoid placing your detectors too close to windows or doors. While fresh air might seem helpful, it can disperse carbon monoxide. This prevents the detector from sensing the gas. You could miss a CO leak if you place your detector near a window or door. Additionally, drafts from open windows or doors can make your detector less sensitive to low levels of carbon monoxide. This is especially important when you open windows and doors more often during colder months.

In the Garage

Do you have an attached garage? Place a carbon monoxide detector near it. You see, carbon monoxide can seep from the garage into your living spaces. Car exhaust or power tools left running can also generate CO. So, placing a detector near the door leading into your home makes sure that the gas from your garage doesn’t enter your house unnoticed. Consider placing one in the room above the garage as well. It’s because carbon monoxide can travel through shared walls or ceilings. 

How to Maintain Carbon Monoxide Detectors

Carbon monoxide has no odor and is invisible, so poisoning can occur before you know it. Here are the top tips to keep your CO detectors in good working order:

1. Test the Alarm Regularly

Testing your carbon monoxide detectors is one of the easiest ways to make sure they work. To do this, press the test button on each unit at least once a month. The sound of the alarm should be loud and clear. You should also be able to distinguish it from a smoke detector. Testing your detector monthly makes sure the sensor is active, and the alarm is functioning as it should. If the alarm doesn’t sound when you press the button, check the batteries, call a professional, or consider replacing the unit.

2. Change the Batteries At Least Once a Year

Changing the batteries in your carbon monoxide detectors keeps them in top shape. According to the US Consumer Product Safety Commission (CPSC), you should change the batteries at least once a year unless the detectors have sealed 10-year batteries. 

In particular, weak or dead batteries can prevent your unit from detecting carbon monoxide. It can also render the alarm useless when you need it the most. A good rule of thumb is to change the batteries when you change your clocks for daylight savings time. This way, you’ll easily remember. 

3. Clean the Detector

Dust and dirt can clog up your carbon monoxide detectors' sensors. This can result in false alarms or, worse, no alarm at all. To prevent this from happening, clean your detectors regularly. Use a dry, soft cloth to wipe the outside and inside of the unit. If you notice heavy dust buildup, use a soft brush, paintbrush, or gentle vacuum to remove it. Plus, follow the manufacturer’s instructions to avoid damaging the sensitive parts. Cleaning once every three to six months helps keep your detector in top shape. 

4. Replace Old Detectors

Even the best carbon monoxide detectors don’t last forever. Most units have a lifespan of eight to 10 years. After this period, the sensors become less effective, and the alarm may not sound when needed. Check the manufacturer's guidelines on when to replace your unit. If it’s older than 10 years, don’t wait—replace it immediately. 

5. Investigate False Alarms

If your carbon monoxide detector goes off and you don’t see any plausible reason, don’t ignore it. Investigate the cause of the alarm. A false alarm could be triggered by dust or dirt inside the unit. It could also indicate the detector is not in the right spot. It’s also a good idea to check the batteries—low battery power can sometimes cause false alarms as well. If you're still unsure about the cause, call a professional. 

6. Read the Manual

Every carbon monoxide detector is different, so always check the manufacturer’s manual for specific maintenance tips. The manual will tell you how to clean, test, and care for your unit. It will also tell you its expected lifespan and any particular features your model may have. 

When to Replace Your Carbon Monoxide Detectors

Replacing your carbon monoxide detector on time is important for your safety. Most detectors last for eight to 10 years. After that, their sensors become less reliable, so they might not detect carbon monoxide properly. Make sure to replace your detector every eight to 10 years. If you press the test button and the alarm doesn’t sound or the sound is weak, replace it as soon as possible. 

In some cases, carbon monoxide detectors become defective before the eight-year mark. Regularly check your carbon monoxide detector for any physical signs of damage, such as cracks, burns, or broken parts. If the detector looks damaged, it may no longer work. Consider replacing the unit in such cases.

The same thing applies if the test button doesn’t work.  Your detector should produce a loud sound when you press the test button. If it doesn’t or it sounds weak, call a professional to inspect it. If they tell you to replace the unit, do it. 

Do I Need Carbon Monoxide Detectors in Every Room?

Yes, you need carbon monoxide detectors in every room. According to CPSC, CO detectors should be installed in every bedroom. Carbon monoxide is a colorless, tasteless, and odorless gas that’s hard to detect, so you need alarms to warn you while you’re asleep. Putting detectors in every room also ensures that every family member is alerted during an emergency. 

How Many Carbon Monoxide Detectors Do I Need per Square Foot?

You need one carbon monoxide detector per 10,000 square feet, which is roughly one detector every 100 feet. However, you should note that one carbon monoxide detector is not enough for one house since experts recommend placing one in each bedroom and floor. So, you need more CO detectors even if your house is less than 10,000 square feet. 

Is One CO Detector Enough?

One CO detector is enough for one bedroom. At a bare minimum, you should have at least one carbon monoxide detector on each floor. However, you should install one detector for each bedroom for maximum protection. 

What Houses Should Have Carbon Monoxide Detectors?

All houses should have carbon monoxide detectors. Whether you’re living in a small apartment or a huge house with many floors, CO detectors are a must. It’s especially important for houses with furnaces, stoves, generators, water heaters, and other gas appliances.

Do You Need a Carbon Monoxide Detector if There Is No Gas?

Yes, you still need a carbon monoxide detector if there is no gas. Carbon monoxide can come from other sources, like a wood stove, a fireplace, or a car left running in an attached garage. CO can also build up in your home from any source that burns fuel, not just gas.

Conclusion

Knowing how many carbon monoxide detectors you need keeps you and your loved ones safe. It alerts you when carbon monoxide levels rise, especially when you're sleeping.

But carbon monoxide detectors are just one part of the equation. You also need fire prevention tools like smoke detectors, fire blankets, and fire sprays to fully protect your home. CO detectors and fire safety tools work together to make sure you're ready for any emergency. Having them protects you from CO poisoning and fires.