Breathe Easy with the 12 Best Carbon Monoxide Detectors

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Carbon monoxide (CO) is a colorless, odorless, and tasteless gas that is toxic, and the risk for exposure to it increases during this time of year—when temperatures take a turn and colder weather prompts us to run heaters in our homes.

CO can be found in fumes produced by items like power generators, stoves, lanterns, grills, wood-burning fireplaces, gas ranges, or furnaces, and also the vehicles we drive every day. If CO builds up indoors or in your car, it can overcome you quickly and without warning, which is why it's not surprising that every year more than 400 people in the U.S. die from accidental carbon monoxide poisoning, according to the Centers for Disease Control and Prevention. The most common symptoms of CO poisoning are headache, dizziness, weakness, nausea, vomiting, chest pain, and confusion.

As grim as this all sounds, prevention is possible and costs less than $20. Here are our recommendations for carbon monoxide detectors along with valuable advice before you shop.

Best Carbon Monoxide Detectors

• Best Overall: First Alert Hardwired Talking Smoke and CO Detector

• Best Upgrade: Kiddie Carbon Monoxide Detector AC-Powered with Battery Backup

• Best Value: Kiddie Battery Operated CO Alarm

• Best Digital Display: First Alert Dual-Power Plug-in CO Alarm

• Best Mounting Option: Kiddie Nighthawk AC Plug-in with Battery Backup
  
  The Expert: I’ve worked in the home security industry for the better part of a decade testing, reviewing, and writing about home security and home safety equipment. Along with writing disaster preparedness guides for homeowners, I’ve also done extensive research on air quality and pollution. As a parent of young children, I’ve used and regularly tested environmental monitoring devices like smoke and carbon monoxide alarms on every level of my home.

How to Choose a Carbon Monoxide Detector

Power Sources

Carbon monoxide (CO) detectors can be battery-operated, plug-in, or hardwired (with backup batteries for power failures). Battery-operated alarms are easy to install and budget-friendly, but have disadvantages.

In exchange for the work of wiring in a carbon monoxide alarm, you’ll get an extended lifespan of 7 to 10 years. Battery-powered devices, however, may need to be replaced every 3 to 5 years. Double-check city building codes because hard-wired smoke and carbon monoxide detectors are increasingly required in new construction.

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Sensor Types

Carbon monoxide alarms use a variety of detection methods, and the kind of sensor is often directly related to the power source. Keep in mind that carbon monoxide alarms can also include smoke detectors, which have ionization sensors for detecting fast-burning fires or photoelectric sensors to detect smoldering fires. Some smoke detectors have both and are therefore called dual-sensor alarms.

Interconnected

If you live in a multilevel home, consider hard-wired or smart carbon monoxide alarms that can be interconnected. By placing several units around the house, you create a network for better coverage and detection. According to the U.S. Consumer Product Safety Commission (CPSC), carbon monoxide alarms should be placed about 5 feet off the ground on every level of the house (except basements and attics) and outside of sleeping areas.

UL Certified

UL-certified carbon monoxide alarms are recommended because they’ve been third-party tested and meet the UL-standards for consumer safety and effectiveness. This is important in carbon monoxide detection as alarms are required to sense CO levels consistently at a fairly low threshold.

Extras

Basic detectors are simple alarms, but sophisticated models come with features like digital displays, LED warning lights, voice alerts, location detectors that pinpoint the source of a leak, or memory functions that record levels of carbon monoxide over time. There are also smart carbon monoxide detectors that connect to your home's digital ecosystem.

How We Evaluated Carbon Monoxide Detectors

We researched carbon monoxide detection through the US Consumer Safety Commission and connected with a fire protection expert from UL Standards (Underwriter’s Laboratory) to better understand critical features in residential carbon monoxide detection.

We also relied on the research of Rachel Klein, who sifted through user reviews to determine how these detectors performed in the real-world. The results of our combined efforts are high-quality, four-star rated models that offered a variety of desirable features. Each device we reviewed and recommended below is UL-certified and also specifies dimensions so you can map out how much space is required for installation. These are the best carbon monoxide detectors to buy now.

Hardwired Talking Smoke and Carbon Monoxide (CO) Detector

Combining carbon monoxide and smoke detection into one device makes sense. This talking model from First Alert is packed with even more functions, like programmable locations and voice alerts, into a relatively affordable package.

Since this combination CO and smoke alarm is hard-wired, it comes with a 10-year warranty and can connect with other First Alert detectors to provide whole-home environmental monitoring. Watch out for triggering false alarms though. At 85-decibels, the neighbors are definitely going to notice.

Carbon Monoxide Alarm AC-Powered with Battery Backup

This carbon monoxide detector is another customer favorite. The plug-in unit is well-priced, fairly compact, has a memory feature that records carbon monoxide readings, and includes an 85-decibel alarm.

In the event of a power failure, two included AA batteries serve as backup. Given the smaller footprint, its test button is a thin bar that isn’t designed as well as that of some other units, but the easy plug-in installation is a major perk.

Battery-Operated Carbon Monoxide Alarm

If you’re looking for a reliable yet budget-friendly carbon monoxide detector, this a good bet. It checks the boxes for basics you need for continuous monitoring, including a pulsing red LED warning light and an 85-decibel alarm that trigger simultaneously if carbon monoxide is detected.

There’s also a sizable test-and-reset button to ensure the unit is working. It runs on two AA batteries, which are included.

Dual-Power Carbon Monoxide Plug-In Alarm

The blue backlit LED display on this plug-in carbon monoxide detector makes it easy to see CO readings—a definite plus in an emergency situation—and power level of the two backup AA batteries. It also has a peak memory feature that records readings.

Other highlights include a test-silence button to ensure the unit is functioning properly, an 85-decibel alarm, and a limited 7-year warranty.

Nighthawk AC Plug-in Operated Carbon Monoxide Alarm

Even without a backlit display, the popular plug-in Kidde Nighthawk ranks highly for ease of reading, plus it has a memory feature for recording peak CO levels. It has an extension cord that allows you to set it on a shelf if you'd prefer that type of placement over keeping the entire unit wherever your outlet is.

Included with the Nighthawk is a 9-volt backup battery so you don’t have to worry about protection during a power outage. It has a standard 85-decibel alarm, and there’s a blinking dot in the corner of the display to let you know the device is functioning properly.

Carbon Monoxide Alarm with 10-Year Battery and Digital Temperature Display

Sleek and slim, this battery-operated carbon monoxide detector packs in plenty of features. It also doubles as a digital clock, so it's right at home on a nightstand or placed on a shelf. Its bright blue backlit LED display shows the temperature as well as carbon monoxide levels.

Other highlights include a 10-year lithium battery, an 85-decibel alarm, and a 10-year limited warranty. It doesn’t provide the kind of comprehensive coverage that full-size carbon monoxide detectors deliver, but it’s a nice supplemental device for extra peace of mind.

Wireless Interconnected Carbon Monoxide Alarm with Voice and Location

Although this battery-powered carbon monoxide detector comes with a big jump in price compared to some of our recommendations, it packs some great features. It has a voice alarm, plus it can be connected to other units to create a wireless network for blanket coverage in your home.

Once the exact location of carbon monoxide is detected, it pings the other units and triggers the voice alarm. What is missing is an LED warning light, a feature included on detectors that cost much less than this First Alert. Two AA batteries are included for installation.

Battery-Powered Smoke & Carbon Monoxide Detector

This combination smoke detector and carbon monoxide alarm features voice alerts, LED lights, and a low-battery warning—all for a similar price point to other devices that only offer CO detection. If that doesn’t convince you, this Kidde alarm runs on AA batteries instead of the typical (and more expensive) 9-Volt.

A few reviewers reported that the unit was very sensitive to any type of heat and threw more false alarms than other detectors—just something to keep in mind as you do your own further research.

3-in-1 Smoke, Fire, and Carbon Monoxide Smart Alarm

There are many carbon monoxide detectors that come with smoke detectors that have single sensors—either ionization or photoelectric—but this one features a dual sensor to detect both fast-burning and smoky fires. The device is powered by a sealed 10-year battery and features microprocessor technology to cut down on false alarms, and a hush button in the event that they happen.

Overall, it gives you great bang for your buck in terms of complete protection, minus extras like a voice alarm and digital display.

Nest Protect

If you have a Google Home ecosystem, this is the carbon monoxide and smoke detector combo you'll want. It sounds the alarm for dangerous levels of carbon monoxide and has a split-spectrum sensor that detects fast-burning fires and smoky, smoldering ones by combining a traditional infrared photoelectric sensor with a blue LED.

When the alarm is triggered, you’ll get notifications on your phone, plus the app allows you to test alarms and get performance reports.

You won’t have to worry about checking the battery or sensors, as the Nest Protect runs diagnostics 400 times daily. It also doubles as an optional hallway light that’s triggered when you walk underneath. The device also comes in a hardwired version if you prefer that to batteries.

Hardwired Carbon Monoxide Detector

This might not be the best looking carbon monoxide detector in the bunch, but safety comes first—and on that, it delivers. The hardwired unit has a 9-volt battery backup in case of a power outage, with an advanced electrochemical sensor and microprocessor that helps cut down on the frequency of false alarms. It’s also interconnectable with up to 18 compatible devices for blanket coverage.

Other highlights include a visual indicator that shows which unit triggered the alarm within the network, an 85-decibel alarm, and a test and silence button. The drawbacks are no voice alarm or LED warning light.

Portable Carbon Monoxide Detector

This ingenious little keychain is a carbon monoxide detector in disguise. It has an electrochemical sensor, with a combined microprocessor and pump that produce CO readings on the display.

If levels are dangerously high (200ppm or more), the device sounds a 90-decibel alarm—along with a flashing red light and strong vibration. It’s powered with a 9-volt battery and made for outdoor use, with an IP67 waterproof rating. It’s ideal for travel, but is also suitable for camping, motorhomes, tents, and basements.

Combination Smoke and Carbon Monoxide Detector (6-Pack)

It makes sense that wireless interconnected carbon monoxide and smoke detector combos, often sold in sets of three or more, are gaining popularity. After a short installation process, you’ll have a network for coverage across your home.

X-Sense detectors are relatively new to the market and generally highly rated. It features an electrochemical carbon monoxide detector and a photoelectric sensor for smoky fires, though it does lack an ionization sensor for fast-burning fires.

Still, the bright blue backlit LED display shows real-time carbon monoxide levels, battery life, and operational status, plus the unit self-tests its battery and sensors every 60 seconds. There’s also a test and silence button and a standard 85-decibel alarm.

Expert Kaz Weida Finds Out How Often a Carbon Monoxide Alarm Should Be Replaced. The Answer Might Surprise You.

Where should carbon monoxide alarms be placed in a home for optimal detection?

It’s critical that consumers follow the manufacturer’s instructions on where and how to install the CO alarm. Failing to do so could introduce variables that comprise the alarm’s performance and effectiveness—and with carbon monoxide, there can be serious consequences.

Time is also an important consideration. CO alarms should be replaced within seven years of the manufacture date marked on the product because the CO gas sensing element of the device is considered a limited-life component.

Which features are absolutely essential for homeowners to have in a carbon monoxide alarm?

You can choose a combination smoke and carbon monoxide alarm, and you can choose among battery-powered, hardwired, or plug-in power sources. If the alarm is being used in a residence, it’s important to look for one that is third-party certified to UL standards and to follow the manufacturer’s instructions on where and how to install the device.

We call them carbon monoxide detectors, but that’s sort of a misnomer. What’s the difference between carbon monoxide detectors and carbon monoxide alarms?

While both alarms and detectors sense whether carbon monoxide concentrations have reached unsafe levels, the key difference between the two is often dependent on where they are commonly used—in a residential or commercial setting.

Most consumers are buying carbon monoxide alarms for their homes. Carbon monoxide detectors are devices connected to an alarm control unit with a sensor that responds to carbon monoxide, and are typically found in a commercial setting where they are installed, maintained, and inspected by a professional.

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