The Best Carbon Monoxide (CO) Detectors of 2019

From smart, energy-saving carbon monoxide detectors to ones that simply plug into an outlet, we found the best CO detectors available to keep your home and family safe.
Written by | Updated September 13, 2019
Best Overall
Nest ProtectGoogle Nest Protect Smoke/CO Detector
  • Smart home compatibility
  • Dual functionality
  • Smart home compatibility
  • Dual functionality
Best Value
Kidde Carbon Monoxide DetectorKidde Plug-In CO Alarm
  • Affordable price tag
  • Digital display
  • Affordable price tag
  • Digital display
Best Voice Control
First Alert Carbon Monoxide DetectorFirst Alert Onelink Safe & Sound
  • Amazon Alexa integration
  • Long battery life
  • Amazon Alexa integration
  • Long battery life

SafeWise News Alert: September 2019

On September 10, 2019 the House unanimously passed a $300 million bill that requires carbon monoxide detectors in all federally subsidized housing units. The move comes after more than a dozen residents died from carbon monoxide poisoning over the past 16 years. Four of those deaths occurred in 2019. 

The bill allows for $300 million over three years to purchase and install CO detectors in public housing—where more than four million Americans live. A similar proposal is on the slate for Senate review.

Bottom Line: Google Nest Protect Offers More Than Basic CO Protection

Nest was one of the first companies to combine a smoke alarm, CO detection, and smart tech. Because both hazards can be devastating, we like that you can get double the protection in one device. The addition of mobile alerts via the Nest app ensures you’ll get early warning of danger no matter where you are.

But you’ll pay for the Nest Protect’s extra protections—it starts around $120, which is a lot compared to simpler CO detectors that are under $20.

Compare CO Detectors and Alarms

After hours of research and testing, we’ve found the best carbon monoxide detectors available. From basic battery operated to smart devices, you can find the top options here.

Smart Features
Digital Display
Learn More
Best Overall
Best Value
Best Voice Control
Budget Pick
Easy Installation
Best Basic Protection
Nest Protect Kidde Carbon Monoxide Detector First Alert Carbon Monoxide Detector First Alert CO400 Carbon Monoxide Alarm Kidde Battery Powered CO Detector First Alert CO605 Carbon Monoxide Detector
Nest Protect Kidde Nighthawk First Alert Onelink First Alert C0400 Kidde Battery-Operated First Alert CO605
$115.00 $26.84 $175.49 $13.99 $54.49 $24.77
Electrochemical sensor Electrochemical sensor N/A Electrochemical sensor Electrochemical sensor Electrochemical sensor
Yes No Yes No No No
Yes Yes No No Yes No
View on Amazon View on Amazon View on Amazon View on Amazon View on Amazon View on Amazon

Data effective 9/13/2019. Offers and availability subject to change.

CO Detector and Alarm Reviews

Google Nest Protect: Best Overall Carbon Monoxide Detector

Best Overall
Nest Protect

Nest Protect combines smoke and carbon monoxide detection and works with an app. When you download it, you can get alerts to your phone and even silence alarms if necessary. With state-of-the-art sensors for both fire and carbon monoxide, this alarm is one of the best for homeowners or renters.

You can’t change the batteries in this unit, so you’ll need to replace the whole thing once it expires. But at $120, Nest Protect is still a good value if it lasts for its full life expectancy of 10 years


  • Works with other smart home devices
  • Doubles as smoke detector
  • Comes with battery or hardwire capabilities
  • Features voice notifications


  • When the battery dies, you'll need a new alarm

Kidde Nighthawk: Best Value

Budget Pick
Kidde Carbon Monoxide Detector

As the world’s largest fire safety product manufacturer, Kidde also produces high quality carbon monoxide detectors. While it’s not the cheapest option on our list, the Nighthawk packs in the most features for the best price.

With a digital display, you can read your home’s carbon monoxide levels easily. Plus, the device refreshes its data every 15 seconds so you’ll know if something isn’t right. If your device sounds, you’ll definitely hear it. This carbon monoxide alarm lets out an 85 db beep that’s as loud as a blender.


  • Affordable price
  • Digital display
  • Positive customer reviews
  • Backup battery


  • Not compatible with home automation
  • Hardwired only
Best Voice Control
First Alert Carbon Monoxide Detector

This smart smoke and carbon monoxide detector can do a lot. Using your home’s wifi, the alarms can talk to one another and synchronize to alert you if there is a gas leak or fire. You can also control it from your Apple device through an app, so you can silence the alarm or get notifications on your phone.

Onelink doesn’t have a battery compartment that you can access, so when it dies you’ll need to get a new CO detector. With a price tag over $200, that steep replacement cost might be more than some want to pay.


  • 10-year battery
  • Mobile app
  • Voice alarm
  • Syncing system
  • Built-in smoke alarm


  • Big price tag
  • When the battery dies, you'll need a new alarm

First Alert CO400 Alarm: Best for Your Budget

Budget Pick
First Alert CO400 Carbon Monoxide Alarm

This sweet little unit ensures that money stays in your pocket and your family stays safe—all while keeping safety on the down-low with its slim design. The First Alert CO400 Carbon Monoxide Detector doesn’t require an outlet, so it can be placed anywhere, which gives you a lot of options.

It’s nice that you can change the batteries in this CO alarm, but the battery compartment is difficult to get into. Our advice: take a few deep breaths before swapping out the batteries.


  • Cheap price tag
  • Dependable readings
  • Basic design


  • Tricky battery compartment
  • No smart home features

Kidde Battery-Operated: Easy Installation

Easy Installation
Kidde Battery Powered CO Detector

Kidde’s battery-operated CO detector is equipped with an electrochemical sensor, which is the best way to detect CO in your home. The digital display makes it easy to monitor levels of carbon monoxide. Plus, an 85 dB alarm ensures you won’t miss an alert.

You’ll appreciate the simple setup and operation of this device. All you have to do is pop in some batteries and mount it on the wall. But simplicity comes with drawbacks—there’s no smart home compatibility in this detector.


  • Digital display
  • Frequent readings
  • Easy installation
  • Affordable price


  • No home automation

First Alert CO605 Detector: Best Basic Detection

Best Basic Protection
First Alert CO605 Carbon Monoxide Detector

This stripped-down alarm doesn’t come with any extras, but the First Alert CO65 gets the job done. Several user reviews praise this simple device for saving their lives. If you’re looking for a straightforward CO detector that has a good track record for detecting dangerous gas levels and sounding the alarm, this device is a solid choice.

The cheap price makes it easy to buy multiple units for full coverage throughout your home. But if you want smart home features or a digital display, keep looking.


  • Small size
  • Easy installation
  • Backup battery


  • No frills

Types of Carbon Monoxide Detectors

There are several types of carbon monoxide detectors available for purchase. While they all have varying levels of sophistication, all models will alert you if dangerous levels of carbon monoxide accumulate. Some include multiple functions. Here are the different types out there:

  • Dual-function
    These devices have a digital screen to show you levels of carbon monoxide in your home.
  • Digital
    These devices have a digital screen to show you levels of carbon monoxide in your home.
  • Smart
    Smart carbon monoxide alarms are the most advanced option available. They do their own diagnostics to make sure they’re working properly and sync with home automation apps so you can monitor your home from afar.
  • Hardwired
    Instead of using batteries, these carbon monoxide detectors are wired into your home’s electrical grid. Unless the power goes out, you won’t have to worry about devices losing battery and failing to work.
  • Battery-operated
    This type is as basic as they come. Battery-operated carbon monoxide detectors may or may not have a digital screen. You’ll need to check your batteries once every three months to ensure your detectors are working properly.

Things to Consider When Buying A Carbon Monoxide Detector

Before you buy, it’s good to break down exactly what to look for in a carbon monoxide detector. We’ll highlight several key factors that were part of our decision-making process to help you become a more informed consumer, but if you’d like to skip to the details on our recommended models, you can do that here.

What Are the Symptoms of Carbon Monoxide Poisoning?

If you have carbon monoxide poisoning, you may feel dizzy, become nauseous, throw up, develop a headache, get confused, or pass out. It’s often been said that the signs of CO poisoning might resemble the flu.

Every year, 400 Americans die from accidental carbon monoxide poisoning (from fuel burning, not fires), and 20,000 are admitted to the emergency room.1 If you become unconscious while carbon monoxide is filling your home, it can be life threatening.

That’s where carbon monoxide detectors come into play. Once installed, they can alert you about high levels of carbon monoxide in your home, which will give you more time to get to safety.

Who Is Most Susceptible to CO Poisoning?

Everyone is susceptible to carbon monoxide poisoning.

But, according to the Centers for Disease Control and Prevention (CDC), children, older adults, people who are physically ill, and pets are more likely to be affected by CO.2 The Mayo Clinic adds that unborn babies’ blood cells take in more CO than adult blood cells, which makes them more susceptible to poisoning.3 Older adults who experience high levels of CO could be more likely to incur brain damage.

When it comes down to it, a CO detector can help save your life and the lives of the people you love. If you want to find out more information about CO detectors, check out our frequently asked questions page.

What to Do If You Suspect High Levels of Carbon Monoxide

If you or your family members experience carbon monoxide poisoning symptoms, quickly walk outside for fresh air and call 911. Even if you start to feel better, you can still have toxic levels of CO in your system and might require medical help. In this situation, it’s a good idea to have your whole family checked for poisoning, including your pets.

Signs of carbon monoxide poisoning don’t always happen right away—it can happen over the period of days and possibly even weeks, depending on the levels of CO in your home.

What Is a Carbon Monoxide Detector?

Carbon monoxide detectors are a lot like smoke detectors, but instead of looking for signs of fire, they detect levels of carbon monoxide. Depending on the brand, detectors operate in one of three ways: with a biomimetic sensor, metal oxide semiconductor, or electrochemical sensor.

Biomimetic detectors use gels that change color after absorbing a certain amount of carbon monoxide—and then a sensor sounds an alarm. Metal oxide semiconductors have silica chips that detect CO and send electrical signals to trigger an alarm.

Electrochemical sensors are considered to be the best in the industry. They use electrodes in chemical solutions that sense changes in electrical currents when carbon monoxide is present, and they sound an alarm.

If you have a professionally monitored security system installed, it should come with a CO detector. Check out our top security providers to see which home security systems include CO detectors with their monitoring plans.

Where to Install Carbon Monoxide Detectors

The Consumer Product Safety Commission recommends putting a carbon monoxide detector outside every separate sleeping area in your home.4 You might also want to add a carbon monoxide detector in your kitchen and basement for added safety. Also, make sure you install detectors close to bedrooms so alarms will wake you up if you’re sleeping.

If you have an attached garage, you’ll want to place a CO detector by the entranceway. A vehicle that’s been left running in a closed space is a common cause for CO poisoning. In the grand scheme of things, it’s better to be overly cautious by placing CO detectors in every room, floor, and hallway than suffering CO poisoning.

Check out our full guide on where to install your own carbon monoxide detectors.

How to Maintain a Carbon Monoxide Detector

Most carbon monoxide detectors last an average of five years. Although the product’s lifetime will vary depending on your make and model, you can still get the most out of your detector by wiping it down weekly to keep it clean from dust and debris.

It’s also a good idea to test your CO detector monthly. Start by pressing the “test” button to ensure the siren works. If your detector is older, you can purchase a carbon monoxide meter to find out if your detector is still fully functional. If the detector doesn’t go off when you test it, it’s probably time to buy a new one.

Know What Can Make Carbon Monoxide Gas

Carbon monoxide (CO) has been called the “silent and invisible killer” because it doesn’t have a smell, color, or taste. It’s one of the most prevalent causes of death due to poisoning in America. Any time you burn something—like gasoline, natural gas, wood, oil, propane, or charcoal—carbon monoxide is released into the air.

In outdoor spaces, this usually isn’t a health hazard because there is enough area for the CO to dissipate, so particles never amount to a toxic level. The danger comes when carbon monoxide is released in a contained area like your home, RV, or garage.

Anything that burns will create carbon monoxide. It’s not just your stove, fireplace, or grill either. Here are some of the things that can create carbon monoxide when turned on:

  • Appliances
  • Gas grills
  • Gas stoves
  • Gas or oil-burning furnaces
  • Fuel-burning water heaters
  • Non-electric space heaters
  • Tools
  • Snowblowers
  • Lawnmowers
  • Pressure washers
  • Generators
  • Non-electric cars, trucks, and boats
  • Chain saws

Know What To Do and What Not To Do

Lighting a fire in your fireplace is okay if it’s properly ventilated. However, if you do the following, you could cause dangerous levels of carbon monoxide to build in your home.


  • Always vent gas appliances properly
  • Get your chimney checked annually to ensure proper ventilation

Fireplace image


  • Never burn gas grills inside your home
  • Don’t use your gas stove/oven for heating
  • Don’t leave the car running with the garage door closed
  • Don’t patch or seal vent pipes with tape or unapproved products or carbon monoxide could leak into your home
  • Don’t ever burn charcoal inside
  • Never run a generator in your home or within 20 feet of your home’s doors, windows, and garage
  • Don’t turn on your car if the tailpipe is blocked (by snow or anything else)

Written by Rebecca Edwards

Rebecca has honed her safety and security skills as both a single mom and a college director. Being responsible for the well-being of others helped her learn how to minimize risk and create safe environments. Learn more

Share this article.
  • Scott T.

    What do you think of our picks for best carbon monoxide detectors and alarms? Is there something we missed, or what else would you like to know?

  • joeandmilly

    Nest is compatible with both Android and Apple, not sure why she wrote only compatible with Apple. nest is owned by Google, which produces the Android OS along with Google Home

    also First Alert is compatible with both iOS and Android as well.

    • Scott T.

      Nice catch! We try to keep things updated, but sometimes tech moves faster than we do. We’ll update it!

  • Sumit

    Check: The Home Security Solution Blog

  • Sumit

    to know more about the digital home security solution check: The Home Security Solution Blog