You need a carbon monoxide detector to protect against accidental poisoning; here are our suggestions
Best Carbon Monoxide (CO) Detectors
Whether you want the cheapest option or the finest technological advancements, we’ve got recommendations for the best carbon monoxide detector.
Our top pick for CO detection is a more traditional Kidde alarm. We’ve also got the ultra-smart Google Nest Protect smoke and carbon monoxide detector and the Alexa-compatible Onelink Safe & Sound, among other recommendations.
Let’s jump into our list of the best carbon monoxide detectors.
We looked at nearly 40 different carbon monoxide detectors and winnowed it down to five top choices.
- : Best traditional option
- : Best combo
- : Best for Google Assistant
- : Best for Alexa
- : Budget pick
|Kidde KN-COPP-3|| |
|View on Amazon|
|Kidde KN-COSM-BA|| |
|View on Amazon|
|Nest Protect|| |
Battery or wired
|View on Amazon|
|Onelink Safe & Sound|| |
|View on Amazon|
|Kidde Battery-Operated KN-Copp-B-LPM|| |
|View on Amazon|
Amazon.com List Prices (as of 05/09/2023 11:05 MST). Offers subject to change.
What to look for in a carbon monoxide detector
In the US, at least 450 people die of carbon monoxide (CO) poisoning each year. Another 50,000 wind up in the emergency room because they’ve inhaled the odorless but deadly gas.¹ You can keep yourself from being one of these numbers by installing a carbon monoxide detector.
Carbon monoxide detector features:
- Smoke alarms
- Voice alarms
- Battery options
- Digital displays
- Smart home compatibility
- Accessible false alarm buttons
You’ll notice that our recommendation for the best carbon monoxide detector doesn’t have most of these features. CO detectors are one of the few home safety items where we don’t see a huge need for super smarts. A garden variety CO detector should do a fine job. But just in case, we’ve included a range of functionality in recommendations.
Kidde Nighthawk KN-COPP-3 Carbon Monoxide Alarm Detector: Best traditional option
The Kidde KN-COPP-3 is the best conventional carbon monoxide sensor. It’s plain, but it does what needs to be done.
We picked this Kidde detector largely because of its reputation. This device may be old school, but it’s one of the (if not the) best-reviewed carbon monoxide alarms we considered.
Both customers and experts alike gave this alarm high ratings, and for good reason. It has a digital display and a generous five-year warranty. And, yeah, it’s plug only, but the six-foot cord means it doesn’t have to be right by an outlet. And because it is a plug in carbon monoxide detector, you won't have to worry about replacing batteries.
Looking for a reliable combo alarm that’s not crazy expensive? We’ve found one.
For those who want the two-in-one safety of a smoke alarm-carbon monoxide detector combo, the KN-COSM-BA is a solid choice. This detector isn’t too expensive, and it runs on batteries rather than needing a plug or wires.
Our favorite feature, though, is the voice warnings aka voice alarm. When the alarm goes off, it vocally announces either “Fire,” or “Warning: carbon monoxide,” so you know what you’re dealing with.
Not necessarily. Carbon monoxide gas doesn’t rise or fall, so it can usually be found in equal concentrations throughout a home.² So while you should put your smoke detector on the ceiling, you might want to disperse carbon monoxide alarms at different levels throughout your home. In that case, it might make sense for some or all of your devices to detect carbon monoxide only.
What if it breaks? Like the KN-COPP-3 carbon monoxide detector, this Kidde device comes with a five-year limited warranty.
The Kidde KN-COSMA-BA doesn’t have a digital display. That means there’s no screen to show the carbon monoxide levels or other metrics. And, like the KN-COPP-3, it wasn’t made for smart home use. You can’t hook it up to your other devices.
Nest Protect Smoke and Carbon Monoxide Detector: Best for Google Assistant
For all you Google Assistant users out there, this one’s for you.
If you swear by your Google Home, or if you’ve already invested in a Google Nest Secure security system, the Nest Protect is a safe bet. It's the best carbon monoxide detector for Google Assistant incorporation. It’ll integrate smoothly with your existing setup. It’s also flexible; you can have it hardwired or just use batteries.
This high-tech smart device features a smoke detector and voice warnings, similar to the Kidde KN-COSMA-BA. You’ll get mobile notifications for alarm events and when the batteries need to be changed. And if you need to turn the alarm off, you’ll tap the Nest app to silence the system from anywhere.
Your device has a two-year limited manufacturer warranty to protect your Nest Protect.
It’s convenient to use remote access to silence your carbon monoxide detector/smoke alarm. But we wish there was also a more obvious button on the Nest Protect for times when your phone isn’t handy.
It took us some digging to realize that the circle in the middle, which lights up when the alarm goes off, is also the silence button. If you forget that little detail, you’ll be forced to listen to the incessant beeping of the alarm while you search for a way to turn it off.
Similarly, the device doesn’t have a digital display to show you the carbon monoxide levels. You’ll have to go to the app.
Onelink Safe & Sound by First Alert: Best for Alexa
Onelink is our pick for Amazon Alexa users.
Onelink is the best option if you want something to work with your Alexa-enabled smart home. The Onelink Safe & Sound is quite similar to the Nest Protect, right down to the smoke detector combo and voice warnings.
But the Onelink offers a little more than the Nest Protect. It has an Alexa speaker built right into it. The speaker doesn’t just control the carbon monoxide detector either; you can use it for other Alexa voice commands.
Lastly, with a Onelink Safe & Sound, you get a three-year warranty. It’s not as extensive as the Kidde detectors’ warranties, but it’s better than Nest Protect’s.
This bad boy’s extremely expensive. For the price of a Onelink, you could buy two and a half Nest Protects and still have enough money to get lunch from the McDonald’s dollar menu.
The Onelink also shares Nest Protect’s lack of a digital display. We think it’s cool to control your detector from a mobile app, but again, it’s also nice to look at the device and immediately know its status.
Also, this is a plug in carbon monoxide detector. The battery backup is for power outages, not for day-to-day use.
Kidde Battery-Operated KN-Copp-B-LPM: Budget pick
The Kidde Battery-Operated KN-Copp-B-LPM is very cheap but minimalistic.
If finances are tight, this is the pick for you. The Kidde KN-COB-LP2 9CO5-LP2 is very inexpensive. But it also comes from Kidde, one of the top carbon monoxide detector manufacturers, so it should be quality even with the price cut.
This battery-powered alarm has a ten-year limited warranty. It takes just two AA batteries, which makes it relatively inexpensive to operate and keeps it safe from a power outage.
To get that low, low cost, Kidde stripped away any extras. This alarm doesn’t have a smoke detector and the digital display is tiny. And it’s not a smart product; you can’t mesh it with your connected home network.
Recap: Best carbon monoxide detectors
Still deciding? Let’s run through each of our recommendations one last time.
- If you seek a basic, traditional option, then the Kidde KN-COPP-3 is what we recommend.
- Try this Kidde KN-COSM-BA alarm to harness the power of both carbon monoxide and smoke detection.
- We recommend Nest’s homegrown product, Nest Protect, for Google Assistant enthusiasts.
- Likewise, the Onelink Safe & Sound is perfect for Alexa lovers.
- If you don’t want to spend much money, try this super cheap Kidde Battery-Operated KN-Copp-B-LPM option.
If you’re looking for a straight-up smoke alarm, check out this guide. Or, if you want more robust protection, consider a full security suite.
Carbon monoxide gas is measured in PPM (parts per million). 101 PPM and over are considered dangerous levels.⁴
According to the CDC, symptoms of CO poisoning are as follows:
- Upset stomach
- Chest pain
These might seem like pretty distinct symptoms at first blush, but things aren’t always so straightforward in the moment.
There’s a famous Reddit tale about a man who believed his landlord was leaving him mysterious notes around his apartment. Turned out, he was actually confused due to high carbon monoxide levels in his rental—he’d written the notes himself.
Having a carbon monoxide detector means that your bewildered brain doesn’t have to play detective. You’ll know that you’re being poisoned and can get out.
Get out. You need to get some fresh air to recover. If someone is experiencing major symptoms, call 911. If not, call your local fire department.⁵
Ring Alarm also has an Alexa-compatible offering called a smoke and CO “listener.” Install this little beauty near your previously existing alarms. When one goes off, the listener lets you know through a mobile notification.
Put a sensor in areas susceptible to CO buildup, like in your garage or RV or near fuel-burning furnaces, stoves, water heaters, fireplaces, and generators.
It’s also smart to put detectors in bedrooms and highly trafficked living areas. You want the detectors to be where you are so that you’ll be notified of high levels immediately.
Yes. For instance, you could try this Forensics Car and Aircraft Carbon Monoxide Sensor. It’s meant for vehicles, but you might be able to use it elsewhere.
There’s also the waterproof, shockproof Sensorcon. You can carry this CO alarm throughout different rooms in your house if needed—though we recommend it primarily for hotels.
A limited warranty can be tricky. It’s left to the retailer’s discretion to decide what the warranty covers. So your warranty might cover accidental damage but not normal wear and tear. Or it might include the hardware but not the repair labor.⁶ Or it might be utterly void if you purchased the product through a third party, even on a reputable site like Amazon.
Be smart about your carbon monoxide detector’s warranty. Read the conditions and terms thoroughly and follow them so you aren’t on the hook for repair and replacement costs.
Fire and rescue departments recommended that you should, at the very least, have one carbon monoxide detector on every floor of your house, even the basement. And if you have an attached garage, you should place a carbon monoxide detector near or above the garage space.
Most Carbon monoxide detectors cannot detect natural gas, as they are entirely different types of gas. Carbon monoxide is generated when fuel burns in low levels of oxygen, while natural gas occurs naturally under high pressure.
- Centers for Disease Control and Prevention, “Carbon Monoxide (CO) Poisoning Prevention.” Accessed December 1, 2021.
- Jason M. Carlton, Intermountain Healthcare, “Protect Your Family: Install Carbon Monoxide Alarms.” February 26, 2014. Accessed December 1, 2021.
- Centers for Disease Control and Prevention, “Frequently Asked Questions.” Accessed December 1, 2021.
- Kidde, “What Are the Carbon Monoxide Levels That Will Sound the Alarm?” October 4, 2019. Accessed December 1, 2021.
- Kidde, “Carbon Monoxide Poisoning FAQs.” Accessed December 1, 2021.
- FindLaw, “What Is the Difference Between a Full Warranty and a Limited Warranty?” Accessed December 1, 2021.
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