Best Carbon Monoxide Detectors

5 Best Carbon Monoxide Detectors

Carbon Monoxide is an extremely dangerous colorless and odorless gas, which is why it is often referred to as “The Silent and Invisible Killer”. Furthermore, this extremely innocuous and fatal gas is released from regular household appliances such as space heaters, grills, stoves, etc.

Because of the ready availability and silent nature of this deathly gas, it’s important to install a carbon monoxide detector in your home. As such, whenever the CO levels exceed beyond a safe point, you will be immediately notified and you can take the necessary actions to protect yourself.

Since carbon monoxide detectors are safety devices, you should be extremely careful while purchasing them. There are a lot of different types of carbon monoxide detectors available on the market and you need to get the right one.

What is a Carbon Monoxide Detector? As the name suggests, Carbon Monoxide Detectors are devices that can detect the presence of carbon monoxide in the atmosphere. They function with the help of a biomimetic sensor, metal oxide semiconductor, or an electrochemical sensor.

  • Biometric Sensor: These detectors use gels that change colors depending on the amount of carbon monoxide they absorb and then they sound an alarm.
  • Metal Oxide Semiconductor: These consist of silica chips that detect carbon monoxide and transmit electric signals to sound the alarm.
  • Electrochemical Sensor: This is the most advanced detection method. It uses electrodes in chemical solutions that can detect changes in electrical currents in the presence of carbon monoxide, and then they trigger the siren.

Carbon Monoxide Detectors are important for the following reasons:

  • 400 Americans die annually from accidental carbon monoxide poisoning. This may occur from fuel-burning sources like stoves and space heaters.
  • Every year, approximately 20,000 people around the country are admitted to an emergency room because of exposure to carbon monoxide.
  • Sometimes people lose consciousness due to carbon monoxide poisoning and that can be fatal.
  • Carbon monoxide is odorless, tasteless, and invisible, which is why you can’t detect it without special devices.
  • Even the symptoms of carbon monoxide poisoning may be mistaken as those of the common flu, which will, in turn, keep you from taking the correct measures.

For all of the aforementioned reasons — and many more — it is absolutely necessary to install carbon monoxide detectors in your home.

To help you make an informed decision, I have reviewed some of the best carbon monoxide detectors on the market.

Best Combination Carbon Monoxide Detectors

1. Nest Protect Smoke and Carbon Monoxide Alarm

Nest Protect is one of the best companies on the market for smart home security devices such as smoke and carbon monoxide detectors. Nest Protect Smoke and Carbon Monoxide Alarm is a 2nd generation smart device with complete smart-home compatibility. Furthermore, as a combination device, it can be used to detect smoke from fires and carbon monoxide levels.

This carbon monoxide detector is Bluetooth and WiFi compatible so you can pair your smartphone however you like. With the WiFi, you can monitor the device even if you’re not in your home. Furthermore, this Nest Protect detector can also communicate via Thread, a low-power smart-home mesh network that can communicate with over 250 devices. As such, if you’re setting up a smart home, this is the perfect carbon monoxide detector for you.

Installation of this carbon monoxide detector may take a while. You can either get the hardwired device or the battery-operated device, whatever suits your needs. You can either mount it on the ceiling via the backplate or mount it on a wall. The device comes with a detailed step-by-step instruction manual on how to install the device and how to connect it to the smartphone app. As such, setting up the device is relatively painless. Being a smart device, it is certainly a little more complex than other non-smart carbon monoxide detectors, but that is well worth it.

Nest Protect Smoke and Carbon Monoxide Alarm also has an attractive design. As far as the smoke detection is concerned, it has a Split-Spectrum Sensor that can detect both slow fires and fast-burning flames. In terms of carbon monoxide detection, you can use the app to monitor the CO levels at all times. Whenever the CO levels get critical, the device will start beeping and send a voice alert clearly stating that the carbon monoxide levels are too high. The alarm rings at a pretty loud 85dB volume so it can wake you up even if you’re asleep.

Being a dual smoke and carbon monoxide detector, Nest Protect is definitely a pretty attractive and cost-effective option. However, it also comes with a very clear and obvious drawback. You cannot install this device in the kitchen area because the smoke detector will constantly get triggered. Considering kitchens are one of the most at-risk locations for carbon monoxide poisoning, this proves to be a major drawback.

Besides that issue, Nest Protect is extremely reliable. It only starts beeping when either the smoke or carbon monoxide reaches critical levels so you won’t get hassled by false alarms. Furthermore, this carbon monoxide detector can also self-test. It checks to see if the batteries, sensors, and the alarms are working correctly. If there are any issues with the device, you’ll receive a push notification via your smartphone app.

There have, however, been complaints that this carbon monoxide detector is prone to false alarms. A few concerned users have noted that after a few years of use, Nest Protect starts giving off false alarms with increasing frequency. However, these claims are few and far better, and they are unverified. In my personal experience, I never experienced any false alarms.


  • Available in hardwired and battery-powered versions.
  • Can connect to a smartphone via Bluetooth or WiFi.
  • Has smart-home compatibility.
  • The alarm is loud and clear.
  • A voice lets you know exactly what the issue is before setting off the alarm.
  • Can self-test.
  • Can detect smoke and carbon monoxide.
  • Cost-effective.


  • Cannot be installed in the kitchen because of the smoke detector.
  • There is no display on the device so you have no option but to use the smartphone app for monitoring.
  • There have been unverified complaints of false alarms.

2. First Alert SCO501CN-3ST

First Alert SCO501CN-3ST is a battery-operated combination smoke and carbon monoxide detector. As such, it can detect both smoke from fires and carbon monoxide levels. It has to be installed on the ceiling or on walls. The best feature here is the customizable Voice Location feature. That feature allows you to set up specific commands for different locations around the house. As such, when there’s smoke or carbon monoxide detected, the alert will first give you a voice notification of which room is affected and by what. As such, you don’t have to go from room to room trying to figure out where the alarm is ringing.

The smoke detector uses photoelectric smoke sensing technology and the carbon monoxide sensor uses electrochemical sensors. Both of them are highly accurate and advanced technologies. There’s a separate LED indicator for carbon monoxide and for smoke. When carbon monoxide levels reach a critical level, the device will beep 4 times and pause before beeping again. That’s the carbon monoxide alarm and it rings at an 85dB volume so it’s loud enough. This device also comes with a Silence button in case you want to turn the alarms off.

You should, however, note that there is no display screen on this carbon monoxide detector. As such, you will be notified when the CO levels get critical, but you can’t see what the levels are in ppm. Furthermore, before reaching critical levels, you cannot see what the carbon monoxide levels are. You also don’t get access to the CO levels history. Furthermore, this carbon monoxide detector cannot be paired with a smartphone so you can only monitor it when you’re in its vicinity.

There have also been several reports of false alarms. Many of the device’s past users have noted that it starts going off for no apparent reason. Furthermore, since this is a combination smoke and carbon monoxide detector, you cannot install it in the kitchen since it will constantly keep ringing.

All things considered, First Alert SCO501CN-3ST is not the most reliable or most effective carbon monoxide detector on the market. This is perhaps one of the only battery-operated combination carbon monoxide detectors that’s available at such a cheap price, which is why I have listed it here. However, it doesn’t have a display for monitoring, nor does it have smart compatibility. The lack of both makes it hard to monitor. Furthermore, there are too many reports of false alarms to dismiss, and that is concerning.


  • Battery-powered so it can be installed anywhere.
  • Extremely cost-effective.
  • Works as a smoke and carbon monoxide detector.
  • Has voice notification to let you know what the problem is and where.


  • No display screen.
  • Can’t check CO levels.
  • No records of past CO levels.
  • Several reports of false alarms.

Best StandAlone Carbon Monoxide Detectors

3. Kidde Nighthawk KN-COPP-3

Kidde Nighthawk KN-COPP-3 is an extremely reasonable hardwired digital-display carbon monoxide detector. While this is a wired carbon monoxide detector, it is equipped with a 9-volt battery backup so it doesn’t turn off even if there is a power cut. Furthermore, it also comes with a 6-foot extension cord that you can use to prop the detector up out of reach from children or pets. These two features — the battery backup and extension cord — negate two of the main drawbacks generally associated with hardwired carbon monoxide detectors.

This carbon monoxide detector comes with a clear display screen. As such, you can easily and constantly monitor the CO levels. The display updates itself every 15 seconds so you always have completely updated readings. However, you can also ask for a readout of that particular second at any time. One of this device’s most interesting features is ‘Peak Level’, which allows you to get a readout of what the highest CO level has been since the last reset. These features allow you to keep track of the CO levels at all times, not just when the alarm goes off.

This carbon monoxide detector also has an incredible range in terms of CO detection. It can detect levels as low as 30 ppm and as high as 999 ppm. However, since 70ppm and above are considered to be critical, the alarm will get triggered as soon as the level reaches 70. The alarm is extremely loud at 85dB so you can be assured that you’ll hear it no matter where in the house you are and even if you’re sleeping.

Kidde Nighthawk KN-COPP-3 also has a self-test button in place. When you hit that button, the device will automatically test all of its functions and a green LED light will indicate if all is functioning as it should. This device has a lifespan of 10 years. While I haven’t personally used this device for such a long time, I have consulted several past users and they all agree that it lives up to the stated lifespan. Furthermore, when the device starts dying, you’ll receive a message “ERR” or “END” in the display. This basically means “End of Life” and you have to get a new detector. However, 10 years is an extremely good lifespan for such a cheap and reliable product.

This carbon monoxide doesn’t have a lot of issues. It does everything that it’s supposed to do. There are no false alarms, there are no quality issues, everything works as it should. The only issues I have are in relation to this type of carbon monoxide detector and this particular product can’t be faulted for them. For one, I’m not a huge fan of hardwired carbon monoxide detectors because they lack portability. Even though this model has taken steps to remedy that by providing an extension cord, I’m still not comfortable with long wires dangling from this device. This device also doesn’t provide printouts of its readings, so if you want to track the readings, you’ll have to take note of them manually.


  • Has a digital display.
  • They’ve provided a long extension cord to make it a little more portable.
  • Has a battery backup so it doesn’t turn off in case of a power cut.
  • Has a loud alarm.
  • Incredibly wide range of CO detection.
  • Can self-test.
  • Has a long lifespan.
  • Gets updated every 15 seconds.
  • Can check the peak levels.
  • Extremely reliable and no complaints of false alarms.


  • Even with an extension cord, it’s not as portable as completely battery-powered devices.
  • Doesn’t provide printouts of readings.
  • Can’t monitor this device from distant locations because it doesn’t have smartphone or WiFi compatibility.

4. First Alert CO400

First Alert CO400 is a battery-powered carbon monoxide detector equipped with an electrochemical sensor, which is widely considered to be the most advanced and accurate means of detecting carbon monoxide levels. As a battery-operated device, it is completely portable and you can install it anywhere you want. This is ideal because you don’t have to worry about tripping on any wires and you can easily keep it out of your children and pets’ reach. However, since this is battery-operated, you’ll have to keep an eye on the device and keep checking on it every couple of months to make sure it’s still working. You don’t have the liberty to completely forget about it.

Setting up and installing this device is extremely easy. You won’t even need an instruction manual, though one is provided. You can place it on a shelf or use the provided hardware to mount it on the wall. The buttons on the device can be used to control the device and are fairly self-explanatory. As soon as you place the batteries inside, it will automatically get turned on. Whenever carbon monoxide levels rise to a critical level, it will set off an 85dB sound that can warn you wherever you are. There’s a ‘Silence’ button the device which you can use to turn the alarm off. However, if you silence it and the problem continues, the alarm will simply start up again.

As such, you can’t completely turn the device off as long as it has batteries. This is a safety feature since it negates the possibility that you might hit silence and forget to turn it back on, thus putting you at risk the next time carbon monoxide levels get critical. However, as necessary as this feature may be, it can also be annoying in certain situations when you hit silence but the alarm simply comes back on over and over.

The biggest and most annoying issue, however, is the display. It only reveals the CO level when it reaches critical levels. You can’t choose to see the carbon monoxide levels under normal situations. As such, this device isn’t useful if you want to keep track of the CO levels over an extended period of time. Furthermore, there have also been complaints that the battery compartment doesn’t shut properly, which leads to the device malfunctioning. This is another pretty serious manufacturing issue.

Finally, this is a one-use device. It will last as long as the battery lasts. After that, you’ll simply have to get a new carbon monoxide detector. However, this battery can luckily last several years, so you don’t have to worry about that for a while. It is also pretty cheap so the cost of replacing the device isn’t steep. When the battery is running low, the device starts beeping to let you know.


  • As a battery-operated device, it’s completely portable.
  • Has the most accurate electrochemical sensor.
  • Extremely easy to install and use.
  • Extremely cheap.
  • Loud alarm.


  • Battery compartment isn’t strong.
  • Needs to be replaced after the battery dies.
  • You have to keep checking to make sure it’s working since it relies on a battery.
  • Hitting ‘Silence’ won’t work if the conditions haven’t gotten better. This can be annoying.
  • You are only warned of the CO level after it reaches critical levels. You can’t check what the CO levels are under normal situations.

5. Kidde KN-COPP-B-LPM

Kidde KN-COPP-B-LPM is a battery-operated carbon monoxide detector with a clear digital display. The display reveals the CO levels in ppm and updates the levels every 15 seconds so you always have accurate data. This device is equipped with electrochemical sensors so it is more accurate than most other carbon monoxide detectors on the market. It has an extremely wide range that can detect CO as little as 11 ppm and as high as 999 ppm.

It sets off an 85dB alarm if it detects 70ppm of carbon monoxide for 60 to 240 minutes, or 150ppm of carbon monoxide for 10 to 50 minutes, or 400ppm of carbon monoxide for 4 to 15 minutes. As such, the urgency of the alarm increases with the levels of CO. In addition to sounding the alarm, the LED light in the device will also start pulsing red when the carbon monoxide level is critical. The alarm is loud enough to hear even in your sleep and the time periods for the alarm ensure that you don’t get false alarms if there’s a sudden temporary spike in CO levels for some reason.

This is a battery-operated device so you can install it anywhere you want. You can keep it on a shelf or mount it on the wall, whatever suits you best. This carbon monoxide detector also has functions for Test and Peak Level. The ‘Test’ button will engage the self-test mode so the detector will analyze all of its functions to make sure it’s working as it should. The ‘Peak Level’ button will display the highest recorded CO levels since the previous reset. This allows you to keep track of CO levels over an extended period of time.

The sensor on this carbon monoxide detector has a lifespan of seven years and the battery has a lifespan of about 5 years. As such, it has a pretty decent lifespan and the battery can simply be replaced after it runs out, you don’t have to replace the entire device.


  • As a battery-powered carbon monoxide detector, you can install and set it up anywhere at all.
  • You don’t need to replace the entire device when the battery dies.
  • You get a warning when the battery starts running low.
  • The internal memory can retain all the information regarding past CO levels in case you ever need to refer to it.
  • You can view the peak CO levels whenever you want.
  • Displays the CO level all the time, even under normal situations.
  • Only sets off the alarm under conditions of sustained critical levels of carbon monoxide.
  • Easy to use.
  • Alarm is loud.


  • The batteries aren’t rechargeable.
  • You can’t simply install and forget about the device. You have to keep occasionally checking to make sure that the battery is working.

What are the different types of Carbon Monoxide Detectors?

The following are all the different types of carbon monoxide detectors based on their functionality and power source.

Digital Carbon Monoxide Detectors

These carbon monoxide detectors are equipped with a digital screen that can show you the level of carbon monoxide in your home. As such, you can monitor the levels regularly instead of only being alarmed when the levels rise to a critical condition.

Smart Carbon Monoxide Detectors

These are the most advanced carbon monoxide detectors on the market. In addition to a digital screen for you to monitor the CO levels, they can also be paired with a smartphone so you can monitor the device from afar. The associated smartphone app conducts its own diagnostics and you can monitor the carbon monoxide levels even when you’re not in the house. This is ideal if you have to go away from your home for extended periods, leaving your children or pets behind.

Hardwired Carbon Monoxide Detectors

These carbon monoxide detectors are permanently connected to your home’s electrical grid. They can work 24/7 as long as there are no power cuts. You also don’t have to worry about replacing the batteries regularly.

Battery-Powered Carbon Monoxide Detectors

These carbon monoxide detectors are pretty basic. They don’t always come with digital screens, and they necessitate that you check the batteries every 2-3 months to make sure they’re still working. However, they are a lot more portable so you can carry them around with you. This is suitable for people who travel a lot or those who live in mobile homes like RVs.

Which Factors to Consider when Buying Carbon Monoxide Detectors?

You should take the following factors into consideration when buying carbon monoxide detectors.

StandAlone Unit or Combination Unit

You can purchase carbon monoxide detectors either as an individual unit or as a combination. A standalone unit is one that can only detect carbon monoxide levels and nothing else. Combination units, however, are overhead devices that can detect both smoke and carbon monoxide levels. As such, in addition to carbon monoxide, they can also detect smoke from a fire.

Combination units don’t come with digital displays and are more difficult to monitor as they are installed overhead. However, they are more cost-effective as they can function as a smoke and carbon monoxide detector.

Power Source

As mentioned earlier, carbon monoxide detectors come in various types based on their power source. You have hardwired carbon monoxide detectors and battery-powered ones. The former can function 24/7 without running out and the latter offers portability. Choose the model that suits your needs better.


Carbon monoxide detectors with digital displays allow you to monitor where the CO levels are at all times. Some even allow you to check the history of CO levels over the past couple of weeks or months since the previous reset.


Carbon monoxide levels are measured in parts per million (ppm). Most carbon monoxide detectors start from levels of 30-40 ppm and trigger the alarm when the levels exceed 70 ppm. However, there are some carbon monoxide detectors out there that can also detect levels as low as 10 ppm.


Modern carbon monoxide detectors come with WiFi connectivity so you can pair them with your smartphone app. As such, no matter where you may be, if the carbon monoxide level reaches a critical level, you will immediately receive a push notification in your phone. You can also access the app at any time to monitor the device’s battery level or the current carbon monoxide levels. Furthermore, if you believe that an alarm has triggered erroneously, you can also turn the alarm off remotely.


You should test the carbon monoxide detector’s alarm and sirens to make sure it’s sharp, loud, and clear.  Some detectors also come with beepers or voice alarms. Whatever the alarm method may be, it should be loud and effective. Most people who die from carbon monoxide do so because they have lost their consciousness or because they’re asleep at the time of carbon monoxide poisoning. As such, the alarm should be loud enough to wake you up if you are asleep.

Sensor Life

The sensors in the carbon monoxide detectors generally have a lifespan of 5 to 10 years. You should get a model with a long sensor life so you don’t have to worry about replacing them too often.


Get a carbon monoxide detector that’s easy to install and operate. It should also be clearly visible so you can read the digital display for the CO levels whenever necessary. However, it should also be kept out of reach from kids and pets so they can’t tamper with it.

If you are using a hardwired carbon monoxide detector, your options regarding installation are fairly limited. However, if you are using a battery-powered detector, you can install it anywhere you want to keep it safe.

Safety Certification

Safety devices like carbon monoxide detectors and smoke alarms should always be certified by Underwriters Laboratories Standard to ensure that they meet global standards of safety. As such, make sure that the carbon monoxide detector has been UL certified.


Most carbon monoxide detectors last at least 5 years. As such, you should get a model with a warranty for that period. This will also confirm how much faith the manufacturer has in their product.

Frequently Asked Questions about Carbon Monoxide Poisoning and Carbon Monoxide Detectors

The following are answers to some of the most frequently asked questions about both CO poisoning in general and carbon monoxide detectors in specific.

What are the symptoms to identify Carbon Monoxide Poisoning?

Carbon Monoxide is called the “Silent and Invisible Killer” because it can’t be seen, tasted, or smelt. However, your body will feel its impact so you should be mindful of the following symptoms:

  • You might suddenly feel dizzy or nauseous for no discernible reason.
  • You might want to throw up.
  • You might get a splitting headache.
  • Your cognitive functions might not work correctly as you get confused and forget things.
  • Finally, you or someone around you might pass out.

All of the aforementioned symptoms also resemble those of simple flu, which is exactly what makes it so dangerous. However, if you notice these symptoms and you have some gas appliances working in your home, you should turn them off and get some fresh air.

Which appliances can increase Carbon Monoxide levels?

The following are some common sources of carbon monoxide:

  • Household appliances like gas grills or stoves.
  • Gas or oil-burning furnaces.
  • Water heaters.
  • Space heaters (the non-electric kind).
  • Gas-powered chainsaws.
  • Cars, trucks, motorbikes, boats, and other non-electric automobiles.
  • Pressure washers.

This list is by no means comprehensive. Basically, anything that exudes gas or uses gas/oil/fuel for functioning can potentially release carbon monoxide and cause CO poisoning.

Which groups of people are most susceptible to Carbon Monoxide Poisoning?

Everyone is susceptible to carbon monoxide. However, some groups and demographics are more susceptible than others:

  • According to the Centers for Disease Control and Prevention (CDC), the most susceptible individuals are children, senior citizens, pets, and those who are already suffering from physical illnesses.
  • According to the Mayo Clinic, carbon monoxide can more readily affect unborn babies as their blood cells can absorb carbon monoxide faster than adult cells.
  • Senior Citizens are more likely to suffer from brain damage if exposed to carbon monoxide.

What to do if you detect high Carbon Monoxide?

If you suspect that you have been exposed to high levels of carbon monoxide, take the following steps:

  • Get your entire family out of the house and into fresh air.
  • Call emergency services.
  • Go to the nearest hospital for medical help even if you feel better because the carbon monoxide could still be in your system.

You should note that signs of carbon monoxide poisoning may manifest gradually over the course of several days or weeks as well, especially if the carbon monoxide leak is slow and gradual. This is even more dangerous as you will most likely get used to the gradually-developing symptoms over the course of the weeks.

What’s the best place to install Carbon Monoxide Detectors?

According to the Consumer Product Safety Commission, you should install carbon monoxide detectors in the following locations around your house:

  • Outside all the bedrooms and sleeping locations in the house.
  • In the kitchen and basement as they are most susceptible to carbon monoxide accumulation.
  • Entranceway of an attached garage as a vehicle that’s left running might continue releasing carbon monoxide.

How do you maintain a Carbon Monoxide Detector?

Carbon Monoxide Detectors have an average lifespan of at least 5 years, though it may vary based on the model. However, to maximize the detectors’ lifespan, you should wipe it down on a weekly basis in order to prevent it from collecting dust and debris.

Additionally, you should trigger the “test” button once a month to make sure the siren and the detector works as it should. You can also purchase a separate carbon monoxide detector test and use it once a month to make sure it’s working perfectly.

When to replace a Carbon Monoxide Detector?

Carbon Monoxide Detectors generally have a lifespan of 5-10 years, which is determined by the lifespan of the sensor used in the carbon monoxide detector. You should test your detector regularly to make sure it works well and replace the device when the sensor finally wears out.

How to prevent Carbon Monoxide levels from rising?

You should follow these precautionary tips to prevent carbon monoxide levels from rising:

  • If you light a fireplace, make sure there’s plenty of ventilation around the room.
  • All gas appliances should be properly vented.
  • Get professionals to check your chimney once a year to make sure they’re not clogged.
  • Don’t operate gas grills inside your home or in closed spaces.
  • Don’t use your ovens or gas stoves for heating purposes.
  • Never leave the car running, especially not in a closed garage.
  • Vent pipes should not be sealed or fixed in a DIY-style using tape or other unapproved products as it may cause a carbon monoxide leak.
  • Don’t burn charcoal in closed spaces.
  • Don’t run a generator either in or close to your home.
  • Before operating your car, make sure the tailpipe isn’t clogged with debris, snow, or anything else.


I hope this article has helped you find the best carbon monoxide detector for your personal use. So now you can go to sleep knowing that everyone in your family will be safe from carbon monoxide poisoning.