Best Carbon Monoxide Detectors of 2017

Carbon monoxide (CO) is called the silent killer because it cannot be detected. It is odorless, tasteless and invisible. Which makes it impossible for us humans to know when there is a CO leak. That is why it sits at the top of the list of deaths that occur from poisoning.

Carbon monoxide is created every time you burn something like wood, natural gas, wood, oil, propane or charcoal. When the burn is done outdoors there is not much to worry about as the carbon monoxide is released into the air and quickly dissipates. Which may not be great for the environment, but it isn’t harmful to you.

It is only when you have carbon monoxide in a confined space that you need to take additional precautions. The most common places where carbon monoxide poisoning occurs is in your home, garage or RVs. It is important that you take the proper steps to help you minimize the possibility of an undetected CO leak.

Having a CO detector is not an option, it is a requirement. When you are dealing with an odorless, tasteless and invisible poison, you need to do all you can to keep your family safe.

Here are a few steps you can take to make sure that you keep your family safe from CO poisoning:

  • Understand the risks of carbon monoxide: Risks include anything that burns a fuel like your fireplace or generator. This also includes your car and gas appliances. It is important that any device in your home that burns fuel is properly maintained and kept clean.
  • Keep Vents Clear: You should always make sure that your vents are open and clear. This includes vents for your dryer, stove, furnace and your fireplace. Vents should always be cleared of snow and ice, or any other debris that could block air from getting out.
  • Don’t run gas burning devices in a closed area: Don’t start your car in a closed garage and leave it running, or fire up gas operated lawn equipment indoors.
  • Install more than one CO alarm: Everywhere you could have a CO leak, you should have a CO alarm. They should be placed by the fireplace, the stove, in the basement, in the garage and anywhere else a leak could occur. If you can, choose ones that can communicate with each other. By communicating they can alert you to a leak in the basement while you are in the kitchen.
  • Keep CO alarms properly maintenance: Make sure that you have a battery backup should your power go out. And check the battery backup regularly to ensure it is functioning properly.

With over 400 carbon monoxide poisoning deaths and more than 20,000 emergency room visits a year, it is important to know how to identify the symptoms of carbon monoxide poisoning. While you can’t smell, see or taste carbon monoxide common symptoms of poisoning include dizziness, nausea, headaches, confusion and passing out.

Should you feel like you are suffering from any described symptoms and you have a fuel burning device in your home, you should seek help immediately.

Types of Carbon Monoxide Detectors

Similar to smoke detectors, carbon monoxide detectors work to identify levels of carbon monoxide that exist in your environment. There are three primary ways that they detect CO, the first is a metal oxide semiconductor, this is a three layer device constructed of a metal conductor, insulating silicon layer and a semiconductor silicon layer.

The second option is a biometric sensor, this uses colored gel to determine CO levels. The last option is an electrochemical sensor, this device measures the concentration of gas by oxidizing the target gas to measure it.

Much like there are several ways to detect CO, there are several detectors that you can choose from, these are the most common types of CO detectors:


If you are looking a basic CO detector, this is it. They lack some of the bells and whistles that the more advanced detectors have, but it you change the batteries every three months it should work just fine.


These carbon monoxide detectors are hardwired into your home and use your existing power grid. If you get one of these, look for one that allows a battery back-up. You will want to make sure that the detector still works even if your power has gone out.


Your carbon monoxide detector doesn’t have to work alone. You can get one detector that covers CO and smoke. It can save you from with installing and maintenance a bunch of detectors.


Smart carbon monoxide detectors and alarms are in my opinion worth the money. They do more than just tell you if there is a CO leak, they are also self-sufficient. They do regular checks to make sure they are working correctly, and they also sync with other smart devices in your home. Some also have apps that allow you to know when something has gone wrong even when you aren’t home. Which is awesome if you have pets.


Digital alarms aren’t the most advanced, but these detectors can show you current levels of CO in your home. They will sound an alarm should they detect an abnormal amount of CO.

Options Nest Protect 2.0 Halo Home Alert First Alert OneLink Kidde
Battery operated
Dual CO/Smoke Detector
Android/iOS App iOS
Battery Backup

Nest Protect 2.0

Nest Protect 2.0If you have decided to take the smart approach to CO detection, first good choice, and second the Nest Protect 2.0 is a great way to get started. This hybrid CO and smoke detecting device is not only effective, it’s also attractive. Not that the all white round ones aren’t, but let’s face it we all cringe a little when we see them on the wall or ceiling.

Nest Protect2.0 not only works to keep your home safe when you are there. You also have an app that will send you alerts when you are away. If there is a false alarm you can use the app to easily disarm it. It also has some of the most up to date detection sensors, which makes it our first choice when it comes to CO detectors.

We like the Protect2.0 because you will know the minute you have a leak. So you can get your family, including your furry ones to safety. It also works as a smoke detector which means you can have one lovely device, rather than two plastic disks. I know that looks aren’t everything and its what is inside that matters, but it’s not bad to get both looks and brains.

Nest also allows you to choose between a hard-wired or battery operated device. It can also talk to you. When it detects smoke or CO it will notify you using a human voice to ensure you know that there is an imminent threat. While that may freak you out the first time you hear it, hopefully, you won’t hear it too often.

Nest does care a bit more about aesthetics than some of their competition but that doesn’t mean that Protect 2.0 is lacking anything on the inside. It has a ring of colorful LEDs that alert you to its current status.

  • Blue is setup mode
  • Green is when it’s functioning as normally
  • White is an added nightlight feature
  • Yellow or Orange will indicate there may be a CO or smoke issue
  • Red means it has detected CO or smoke and you need to address it immediately

You don’t even need Wi-Fi to use the Nest Protect, it will still alert you if there it detects carbon monoxide or smoke. And while you should make sure it is running properly especially if you have the battery operated version, it will do its own diagnostics and if something should stop working it will let you know.

If you have more than one Protect they can also communicate with one another. However, if you don have Wi-Fi, which since you are buying a smart CO/Smoke detector you most likely do, you can do some other cool things that are only available using Wi-FI.

You can name your Protect, mine is named George Costanza (it’s a long story). You can a;spopt out of certain features, and receive notifications about software updates. You can also pair Protect with other Nest products like the Nest Thermostat and Nest Cam. Inside your Protect you can find a camera, a nightlight, sensors to detect heat, humidity, occupancy and a mic.

  • It is a refreshingly new design for a CO/smoke detector, and not just a plastic disc
  • You can manage your Nest Protect using iOS and Android apps
  • It plays well with other Nest devices and IFTTT
  • You can silence false alarms using the app from any location

  • It is a little expensive
  • It could use an upgrade that would allow it to store historical data

First Alert Onelink

First Alert OneLinkYou know how you see potential in someone and you are frustrated that they can’t seem to reach it. That is kind of how I feel about the First Alert Smoke and CO detector. While it is better looking (okay, okay looks may matter a little bit), than the traditional round plastic disc, it just comes in short. And the maddening thing is it doesn’t have to. It could live up to its potential.

It’s a smoke detector, and a CO detector, but to say its smart may be stretching things a bit. The thing is it has all of the features that could make it smart, they are all there, voice alerts, in-app silencing features, hard-wired options and notification and alerts, packed into a decent looking device.

It can even communicate with other devices. But for some odd reason, these features do not do what they are supposed to do. The First Alert will work as a smoke and CO detector, that it can do. It also has battery-powered and hard-wired options (which comes with a battery backup). It is backed by a company in First Alert that knows what it is doing when it comes to smoke detectors and other safety devices.

So if you want a smoke/CO detector that can set off an alarm when it detects one of those two options, this is a great device. If you bought it for its smarts, that is where things get a bit tricky. First, it only works with Apple. So if you don’t like or use Apple, you might want to keep looking.

But even if you love Apple, you may still want to keep on walking, the way it works with Homekit is lackluster at best. I am not even sure why it’s there. The app is basic and getting a notification on your smartphone isn’t as quick as it should be. When you are dealing with the possibility of smoke or CO in your home the last thing you want to do is wait even 2 minutes for a notification.

The potential is there, the company knows what it is doing when it comes to providing a solid smoke/CO detector, but it’s in the smart features where it seems to disappoint. I think in time this could be a Nest-like product but for now, it’s a lot to pay for a basic device.

  • It is great at detecting CO and smoke and sounding a loud alarm
  • It looks better than the traditional plastic disc
  • You can get a battery operated or hard-wired device

  • It is priced above what the device can do
  • It only works with Homekit and it doesn’t even do that very well.

Home Alert

Home Alert is not a CO or smoke detector, but it is a device that can make your existing carbon monoxide and smoke detectors smarter. Home Alert has a three part system, first, it listens to your other CO and smoke detectors by connecting to the Gateway, which is the main hub. Second, it provides sensors that can detect flood and freeze emergencies. You can use their app to monitor your home for CO and smoke alerts. You will also get email and mobile alerts if something goes wrong.

Home Alert doesn’t actually monitor for dangerous gas, it listens for your existing CO and smoke detectors to set off an alarm and then it reports the alarm to you. So if you need a CO or smoke detector, don’t buy this device. Alone it cannot detect anything. It only works if you have existing CO/smoke alarms that lack a notification feature.

This is a good option if you have older CO/smoke detectors that you don’t really need to replace. Home Alert can add a level of smart to your existing devices that will allow you to get notifications should one of your existing detectors sound an alarm.

It is a clever way to give you a few smart home features without having to replace your working alarms with more expensive smart alarms and detectors. But at a price of $99.99, you can probably buy a decent CO/smoke detector that comes with those features, and maybe even a few more. Their package does include a hub, and water and freeze sensors, as well as the app.

  • It can turn your existing CO/Smoke detectors into smart devices by reporting alarms to your smartphone
  • If you don’t want to replace your existing devices you can use this to be able to get alerts when ou aren’t home.

  • For $99.99 you can buy an actual smart CO/smoke detector
  • It’s not a CO or smoke detector it just listens for your detectors to sound an alarm then it tells you that an alarm has gone off.

Kidde KN-COPP-3

Kidde KN-COPP-3If you are in the market for an affordable device, the Kidde KN COPP 3 is a good place to start. With over 90 years of experience being one of the world’s largest fire safety device providers, they know what they are doing. In addition to fire safety, they also provide carbon monoxide detectors that allow you to see your CO levels using a digital display.

What makes this CO detector popular is the price, for around $30 you can get a capable device that can alert you when it detects even a small increase in particles in your home. This allows you to place CO detectors around your home without breaking your budget.

With CO detectors that refresh every 15 seconds, you will always know what your carbon monoxide levels are. And if something doesn’t look right you can take immediate action. But let’s say you don’t spend your entire day staring at the CO display, your Kidde will keep checking in and alert you with an 85 dB beep if it detects something unusual.

And unlike most detectors that only alert you in an emergency, the Kidde KN-COPP-3 lets you know if you have a small leak that may become more severe. This buys you time to get your family ready to go to a safe location.

This hard-wired detector comes with a built-in battery back-up and holds the distinction of being the most popular carbon monoxide detector on Amazon.  But if you are looking for a smart CO detector, this one isn’t the one for you.

It lacks the features of a smart device, it cannot send alerts to your smartphone. So you won’t be able to know if something has happened at your home when you are away. You also need to wire them to your electrical grid, which if you are like me, means you are going to need to contact an electrician.

However, if you have existing smoke detectors, and you are just looking for something simple and affordable, the Kidde is a good option, especially when you have elderly family members that live alone. Kidde is a great and affordable way to keep your family safe from CO poisoning. I mean you don’t climb to the top of Amazon by accident.

  • The Kidde KN-COPP 3 is the most popular CO detector on Amazon
  • Although it is hard-wired it comes with a battery backup
  • It’s an affordable sensor that shows your current CO levels
  • It sounds an alarm of 85 dB if it detects a rise in CO levels to alert you

  • It isn’t a smart device and it cannot connect to other devices in your home.
  • You have to hard-wire it into your electrical grid, which may mean that you need an electrician.
  • It doesn’t include a smoke detector.


Halo It’s time to get a little smarter, while Nest 2nd generation is a great smart carbon monoxide and smoke detector, it’s not the only smart alarm on the market. Halo, while one of the newer CO/smoke detectors, is one that you should get to know.

In addition to being a carbon monoxide and smoke alarm, it also knows the weather. Halo can send you weather alerts to your smartphone using the app. You can even choose which type of weather alerts you want to receive.

So if like me you live in a place that may have hurricanes but never snow, you can set Halo to update you should a hurricane form in the Atlantic. But if you are in Denver snow would be something that you would want to know about, so you can have your Halo alert you of a coming snowpocalypse.

Halo reads the temperature and humidity as well, it can also tell a house fire from burnt toast. So if your cooking usually ends up in a smokey mess, Halo won’t set off your smoke alarm unless you have started an actual fire. Like the time I forgot to take the pan off the stove before I tried to flambe some brandyand started a very small fire. Luckily it was easy to put out.

Halo is also a dual threat. It uses two different detection processes. First, it uses the photoelectric process which works to detect smoldering fires, and it also uses ionization that works to detect fast-flames. While both processes are found in other devices, Halo is the first CO/smoke detector that uses both in one device.

Your Halo CO/smoke detector is also very friendly. It has been created to work with as many other smoke and CO alarms as possible. It will even send an alert to other alarms and receive alerts as well.

  • Halo is new and friendly. It is designed to work with other alarms.
  • It gives you the weather, and it will let you decide what weather you want to see
  • It uses ionization to measure temperature and humidity
  • Halo knows when you have burned the pizza and it won’t embarrass you by setting off an alarm

  • Halo is new, so you can expect changes and updates as glitches are fixed.
  • While Halo wants to talk to other devices it’s off to a slow start so you can expect updates as some of the original bugs are worked out.

Understanding Ionization

I am a nerd. If you read my reviews and guides you know this. So as a nerd I need to know what makes things work. So the first thing we need to understand is the ionization process. It is a process by which an atom or a molecule acquires a negative or positive charge. This charge is from gaining or losing firm ions and happens most often in conjunction with other chemical changes.

So how does Halo figure ionization into the speed factor that they claim they have over Nest? First ionization is all about energy. Electrons are raised to higher energy levels by absorbing energy from an external source. If you continue the process over and over there will be a point in which the electron goes completely out of the nucleus, and then you have a positive ion. Electrons in an atom are attracted by the positively charged nucleus.

But how does this work in my CO/Smoke detector?

Ionization CO/smoke detectors have a small amount of radioactive material between two electrically charged plates, which works to ionize the air and cause current to flow between the plates. When smoke enters the chamber it disrupts the current and flow of the ions. This reduction in the flow of the current activates the alarm.

What about photoelectric detection?

The photoelectric effect is in reference to the emission or ejection of electrons from the surface of a metal in response to incident light. When electrons are emitted in this process they are referred to as photoelectrons. This theory implies that this effect can be attributed to the transfer of energy from the light to an electron.

So how does this work in your CO/Smoke detector?

When smoke enters the chamber, the smoke particles scatter the light causing some of the light to hit the sensor. The sensor then sets off the alarm. Photoelectric detectors work best on smoldering, or slow burning fires.

But does this mean Halo is faster than Nest, maybe not. But Halo is the only device that can monitor smoldering flames and fast-flame using one device.

Nest doesn’t currently support ionization and only uses photoelectric detection. This decision to forgo ionization was based on the fact that ionization detectors produce a small amount of radiation. Kidde does both but on different devices.

Halo is the only device that uses both photoelectric and ionization. Photoelectric is the preferred if you are going with just one option, but having both increases the device’s ability to detect both fast-flame and smoldering fires.

In conclusion

First, allow me to thank you for letting me have my moment of nerdiness, I find all of this so fascinating. Now back to what you need to keep your home safe. If you have working CO detectors and smoke detectors in your home, unless you really want smart devices, you should keep them.  You can use Home Alert or another similar product to turn your boring smoke detectors into something smarter that can alert you if something should happen while you are away.

Just make sure you change the battery, that incessant beeping drives my dog Ernie crazy, and it doesn’t put me in the best mood either. You should really consider replacing your detectors if they have been around since the 1970’s. It’s advisable that you replace them every 10 years.

If you want something that looks good Nest is probably the best option. Halo doesn’t look bad, but Nest has made an investment in creating smart home devices that look as good as they work. But if you want a CO/smoke detector that covers all the bases, Halo is a strong contender as it uses both photoelectric and ionization which can identify both smoldering fires and fast-flames.

You can also find more basic devices that will just sound an alarm that are less expensive. At the end of the day, it’s not just important to have both a CO and a smoke detector that works and that will keep your family safe, it’s imperative.

So go check your current detectors, and make sure that you have both a carbon monoxide detector and a smoke detector (or both in one device) and make sure they are working. If they aren’t you should look into a replacement that works for you. There is nothing that we shouldn’t do to keep our homes and families protected.

Jennifer Kelley is an author and technology blogger. She feels weird writing about herself in the third person, but does so when asked. A graduate of The Ohio State University she is a dedicated football fan and a total dork who loves all things written. You can follow her on twitter @theonlyjen

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