Best Overall
Kidde Nighthawk Plug-In Carbon Monoxide Detector
AMAZON
- This attractive, best selling model includes a backup battery, extension cord, and tabletop stand.
This attractive, best selling model includes a backup battery, extension cord, and tabletop stand.
- Some of the other monitors on our list can also detect smoke or gas.
Some of the other monitors on our list can also detect smoke or gas.
Kidde is one of the most trusted brands in this space, known for creating incredibly dependable products. It’s no surprise that it produces the best carbon monoxide detector overall. You can install your new, sleek monitor in just a second: simply plug into a standard 120-volt outlet. In case of a power outage, there’s a 9-volt alkaline battery that will kick in.
With the included six-foot extension cord and tabletop stand, you can put the monitor on a table, counter, or shelf if you prefer. Unlike some of the other monitors on our list, this one exclusively looks out for carbon monoxide (no smoke or gas). But it does that very well. Upon detection, you’ll hear an 85-decibel alarm, while the digital LED display tells you how much carbon monoxide is in the air, updating every 15 seconds.
There’s a smart-hush button that you can use to test or quiet the monitor. With the latter, one push will silence it for eight minutes, giving you the opportunity to handle the issue if possible. The peak level memory lets you know the last time the device detected carbon monoxide or was tested.
Product Details: Detection Type: Carbon monoxide | Alert Type: Alarm | Dimensions: 6.06 x 3.75 x 1.75 inches | Power Source: Plug-in and backup battery | Warranty: 10 years
Best Budget
First Alert Battery-Operated Carbon Monoxide Detector
AMAZON
- There’s a pull-down action chart that tells you what to do in case the emergency alarm sounds.
There’s a pull-down action chart that tells you what to do in case the emergency alarm sounds.
- It’s very short on features like interconnectivity or remote control sync.
It’s very short on features like interconnectivity or remote control sync.
You don’t need all the frills to be effective, which is exactly why this is our best budget pick. It looks for carbon monoxide with an advanced electrochemical sensor, which can accurately detect levels from anywhere in the room. When it locates a dangerous amount, the monitor will sound the 85-decibel alarm.
Panicking? Just pull down the action chart that will tell you exactly what to do next. The device is operated by a replaceable 9 volt battery that works even when there’s a power outage. You’ll notice audio and visual alerts when it’s time for a fresh one. Because the monitor runs on battery power, no real installation is required unless you want to take advantage of the optional wall mount.
To test the monitor, use the test/silence button. You should hear a 5-6 second alarm sequence. With a five-year warranty, the permanent sensor can last up to five years. The end-of-life chirp will give you a heads up when it’s time for a replacement.
Product Details: Detection Type: Carbon monoxide | Alert Type: Alarm | Dimensions: 5 x 3.4 x 1.5 inches | Power Source: Battery | Warranty: 5 years
Best with Gas Detector
First Alert Explosive Gas and Carbon Monoxide Alarm
AMAZON
- The display shows both current and peak levels of carbon monoxide and explosive gasses. In addition to a button on the monitor, you can configure a remote to silence it.
The display shows both current and peak levels of carbon monoxide and explosive gasses. In addition to a button on the monitor, you can configure a remote to silence it.
- It has a more dated look than many other carbon monoxide detectors.
It has a more dated look than many other carbon monoxide detectors.
At all times, this monitor is searching for unsafe levels of carbon monoxide and explosive gasses (natural, methane, and propane). On the display, you can see current and peak levels of both, which helps you stay in the loop and identify any concerning patterns. If it finds them, you’ll be alerted by an 85-decibel alarm. You can mute the alarm one of two ways: by using the silence/test button on the monitor or configuring a standard remote control for use from afar.
It can be set up in just one step by plugging into any AC outlet. You can either keep it against the outlet or use the long attached wire to put it on a nearby surface for greater visibility. If this is your plan, just keep in mind that its appearance is more dated than many of the other detectors we’ve featured.
There’s also a 9-volt battery so if power goes off, you’re still in the know. If the battery needs to be replaced, you can do so via the easy-to-access battery drawer. You’ll know it’s time to replace your unit, not just the battery, when you hear the end-of-life timer. This shouldn’t be for a long time, considering the 10-year warranty.
Product Details: Detection Type: Carbon monoxide and gas | Alert Type: Alarm | Dimensions: 7.25 x 4.25 x 9.06 inches | Power Source: Plug-in and backup battery | Warranty: 10 years
Best Portable
Cekkiena Portable Mini Air Quality Monitor
AMAZON
- The monitor hangs off a lanyard so it’s easier to keep track of. In addition to carbon monoxide, the screen displays the temperature and humidity level.
The monitor hangs off a lanyard so it’s easier to keep track of. In addition to carbon monoxide, the screen displays the temperature and humidity level.
- The one-year warranty is the shortest on our list.
The one-year warranty is the shortest on our list.
In addition to being able to detect carbon monoxide with an electrochemical sensor, this device can also tell you the temperature and humidity level. The numbers are displayed on the color HD 1.9-inch screen. Data is refreshed every two seconds, so you always know what’s happening, when it’s happening.
When the carbon monoxide hits over 50 ppm (parts per million), you’ll hear the alarm loud and clear. The pint-sized detector is on a lanyard, providing maximum portability. This is helpful when you’re traveling to a hotel, Airbnb, or campsite.
The 1000 mAh battery is chargeable via a USB, and can operate for 50 hours straight once fully charged. This is admittedly less than some of the other carbon monoxide detectors run on battery, but makes sense given the size and portability. The other thing to consider is the warranty. At one year, it’s shorter than all the others on our list.
Product Details: Detection Type: Carbon monoxide, smoke, and gas | Alert Type: Alarm | Dimensions: 2 x 0.67 x 3.35 inches | Power Source: Battery | Warranty: One year
Best Hardwired
First Alert Hardwired Smoke and Carbon Monoxide Detector
AMAZON
- You’re able to connect up to 18 compatible devices. If there’s danger, every alarm in your home will sound versus just one.
You’re able to connect up to 18 compatible devices. If there’s danger, every alarm in your home will sound versus just one.
- The side battery compartment makes it tricky to open and replace the battery.
The side battery compartment makes it tricky to open and replace the battery.
This monitor pulls double duty, able to sense carbon monoxide (with an electrochemical sensor) and smoke (with an ionization sensor). If they notice anything, the relevant indicator light will turn on while the 85-decibel alarm issues a warning. Installation is fairly easy, with a quick plug-in power connector to secure the monitor to your hardwiring. It will automatically test its functionality so you know it’s ready to go. With the warranty, you’re covered for 10 years.
Although it’s hardwired, there’s also a 9-volt backup battery so your home is protected even during a power outage. If the battery is low, you’ll hear a chirp. There’s a large, easily noticeable button that’s for both testing the detector and silencing an alarm or low battery warning. If you do need to replace the battery, there’s a tamper resistant compartment on the side—though this can be surprisingly tricky to maneuver. The universal mounting brackets are also tamper resistant.
An especially valuable feature is its compatibility with other BRK or First Alert detectors, which means that if smoke or carbon monoxide are detected, every alarm will sound instead of just the one in the affected area. You can connect up to 18 compatible devices—12 detectors and six other devices like bells or door closers. There’s also a latching arm indicator, which can immediately identify the detector that sensed the danger.
Product Details: Detection Type: Carbon monoxide and smoke | Alert Type: Alarm | Dimensions: 5.6 x 5.6 x 1.9 inches | Power Source: Wire and backup battery | Warranty: 10 years
Best Smart Detector
Google Nest Protect Smoke and CO Alarm
AMAZON
- This monitor detects both carbon monoxide and smoke, and also acts as a nightlight. When something is wrong, you’re alerted via pulsing light, voice announcement, and phone notification.
This monitor detects both carbon monoxide and smoke, and also acts as a nightlight. When something is wrong, you’re alerted via pulsing light, voice announcement, and phone notification.
- Despite being able to last for 10 years, it only has a two year warranty.
Despite being able to last for 10 years, it only has a two year warranty.
What can’t Google do? In addition to all its other technological accomplishments, the brand also makes one of the best carbon monoxide detectors. When the Nest Protect lights up, it’s in one of five colors: blue when it’s first active, green when it’s been tested, yellow when there’s a little smoke or carbon monoxide, pulsing red when there’s a dangerous amount of smoke or carbon monoxide, and white when you walk under it in the dark as a nightlight.
If something is wrong, in addition to the pulsing red light, the Nest Protect speaks up in a friendly, human voice warning you and telling you where the problem is. It also sends a message to your phone (ditto if the batteries are low) and if there’s not actually an issue, you can silence the monitor on the Nest app.
The only downfall is that although the monitor can last for up to ten years, it only has a two-year warranty. This is the second shortest warranty on our list, and significantly lower than the average.
Product Details: Detection Type: Smoke and carbon monoxide | Alert Type: App, voice alert, and light | Dimensions: 5.3 x 1.5 x 5.3 inches | Power Source: Battery or wire | Warranty: Two years
Best Combination Smoke and Carbon Monoxide Detector
Kidde Battery Operated Smoke and Carbon Monoxide Detector
WALMART
- It has a thorough alert system including LED warning indicators, a beeping alarm, and an end-of-life announcement. It also has a 10 year warranty.
It has a thorough alert system including LED warning indicators, a beeping alarm, and an end-of-life announcement. It also has a 10 year warranty.
- You can’t connect this monitor to other ones so that alarms will sound everywhere if one area is affected.
You can’t connect this monitor to other ones so that alarms will sound everywhere if one area is affected.
This multi-tasking monitor is able to detect both smoke and carbon monoxide at the same time, with a photoelectric sensor for the former and an electrochemical sensor for the latter. It runs on batteries, with two AAs included, so it stays on even during a power outage and you can bring it with you while traveling.
The monitor is constantly performing self-checks to make sure it’s operating well (though you should still do manual push tests) and will let you know when it's reaching the end of its life by literally announcing “replace alarm.” This will likely occur at the end of the 10-year warranty. There are three LED warning indicators: green is normal, amber represents an operating error, and flashing red means there’s smoke or carbon monoxide.
When the 85-decibel alarm sounds, you’ll hear three long beeps every 1.5 seconds if the monitor detects smoke and and four quick beeps every five seconds if it detects carbon monoxide. There’s a hush button that will silence the alarm for eight minutes, in case something like burnt cookies triggers it. Note that you cannot interconnect other monitors with this one, so you’ll only hear the alarm in the affected areas.
Product Details: Detection Type: Carbon monoxide and smoke | Alert Type: Alarm | Dimensions: 1.93 x 4.95 x 4.95 inches | Power Source: Battery | Warranty: 10 years
Best Battery-Powered
First Alert Carbon Monoxide Detector
AMAZON
- This is one of the most attractive monitors on the market. It shows the temperature as well as the carbon monoxide concentration.
This is one of the most attractive monitors on the market. It shows the temperature as well as the carbon monoxide concentration.
- Only the temperature is on constant display.
Only the temperature is on constant display.
Part of what makes this one of the best options on the market is its surprisingly stylish design—it looks less like a monitor and more like a modern alarm clock. You can choose whether you want to set it on a surface or mount it on your wall. The backlit digital display shows the temperature at all times, and of course it can also show the carbon monoxide concentration.
Another plus is that you never need to change the batteries (or worry about a power outage), thanks to the built-in 10-year lithium battery. With a warranty of 10 years, the monitor basically has a lifetime warranty.
Using an electrochemical sensor, it accurately detects carbon monoxide better than any other kind. If the monitor detects too much carbon monoxide, an 85-decibel alarm will sound with a pattern of four beeps and a pause. One beep every minute means that the battery is low and five beeps every minute means that the monitor is at the end of its life. There’s also a button to silence or test the alarm whenever you want.
Product Details: Detection Type: Carbon monoxide and temperature | Alert Type: Alarm | Dimensions: 0.94 x 4.75 x 2.63 inches | Power Source: Battery | Warranty: 10 years
Best Plug-In
First Alert Dual-Power Plug-In Carbon Monoxide Detector
AMAZON
- If you lose power, the backup battery will kick in. The plug has an attached wire so you can put the monitor wherever you want.
If you lose power, the backup battery will kick in. The plug has an attached wire so you can put the monitor wherever you want.
- The monitor doesn’t have a built-in stand, so when it’s away from the outlet, you’ll need to pick it up to see the display.
The monitor doesn’t have a built-in stand, so when it’s away from the outlet, you’ll need to pick it up to see the display.
With the backlit digital LED display, you can see the level of carbon monoxide in parts per million, as well as the level of power that’s available, so you’re always informed. In addition to the 85-decibel alarm that goes off when significant levels of carbon monoxide is detected, the monitor has a test and silence button. It also has a seven-year limited warranty, and when it’s nearing the end of its life, a three-chirp alarm will tell you when you need to get a new one.
The plug is attached to a wire so the monitor itself can be located elsewhere than in front of the outlet, which could make detection easier. That said, there’s no built-in stand that will keep it up, so you won’t always be able to see the display.
If you lose power, the backup battery (you’ll receive two AAs) will kick in and take over for the plug. You’ll know it’s working because the display will light up when power comes back. To make sure it’s activated, press and hold the test button. While the battery will do the job for a little while, it’s not meant to work in the long-term. You’ll see and hear low battery signals when it’s time for a replacement, and there will also be a signal when the battery has been removed.
Product Details: Detection Type: Carbon monoxide | Alert Type: Alarm | Dimensions: 3.4 x 1.7 x 5 inches | Power Source: Plug-in and backup battery | Warranty: 7 years