Carbon Monoxide (CO) Detector Buyers Guide

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 May 8, 2019
Best Overall
Nest ProtectNest Protect Smoke/CO Detector
  • Smart home compatibility
  • Dual functionality
  • Smart home compatibility
  • Dual functionality
Budget Pick
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 Safety Alert: 19,000 Firman P03615 portable generators have been recalled—just ahead of hurricane season when portable generators are heavily relied upon. Portable generators are also a source of carbon monoxide poisoning danger. Make sure your portable generator is safe and outfit your home with up-to-date carbon monoxide detectors with backup battery power as part of your prep for the coming storm season.

Read the full recall notice for details about refunds, free inspections, and repair options.

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.

Compare CO Detectors and Alarms

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

Best Overall
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
Check Price on Amazon Check Price on Amazon Check Price on Amazon Check Price on Amazon Check Price on Amazon Check Price on Amazon
Electrochemical sensor Electrochemical carbon monoxide sensor N/A
Electrochemical carbon monoxide sensor
Electrochemical carbon monoxide sensor Electrochemical carbon monoxide sensor
Smart, digital, home automation, dual-sensor with smoke detection, hardwire, battery operated Digital display, hardwire Smart, digital, home automation, dual-sensor with smoke detection, 10-year battery, Apple compatible Battery-operated, test/silence button, end-of-life timer
Battery operated, digital display

Fits any standard outlet, battery backup, single test/silence button
Carbon monoxide + smoke detection
App and home automation
Advanced technology
Hardwires into electrical
Backup battery
Digital display
Carbon monoxide + smoke detection
App and home automation
Advanced technology
Affordable price
Dependable readings
Basic design
Digital display
Frequent readings
Easy installation
Affordable price
Easy installation
Small size
Battery backup
More expensive than others No home automation
Not a dual smoke detector
Most Expensive Difficult battery compartment No home automation No frills

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?

Carbon Monoxide doesn’t have a smell or taste, so you might not know right away that you’re being poisoned, but your body will. 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 the top five security providers, all of which provide 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.

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 test kit to ensure that it’s fully functional. If the detector doesn’t go off when you test it, it’s probably time to buy a new one.

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.

CO Detector and Alarm Reviews

Nest Protect - Best Overall Carbon Monoxide Detector

Best Overall
Nest Protect

Nest Protect is leading the way with home automation and safety products. This particular model 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.


Home Automation
Nest protect works with an app and all other devices in your house, so if there’s a leak, you’ll know about it immediately—wherever you are. Then, you’ll be able to quiet the alarm from your phone.

Doubles As Smoke Detector
Your device will also alert you if it detects smoke in your home, so you get two-in-one. Plus, it’ll be able to tell where the fire is coming from.

Comes With Battery or Hard-Wire Capabilities
You can choose whether you’d like traditional battery operated devices or Nest Protect’s with wires you can connect to your electrical system.

Voice Notification
When Nest protect detects smoke or carbon monoxide, a human voice will notify you of the danger.

Compatible Products
You can order Nest’s camera to keep an eye on your home and see what’s going on during an emergency.


When the battery dies, you’ll need a new alarm
Since you can’t change the batteries yourself or hardwire this unit, you’ll need to replace the whole thing once it expires. Its life expectancy of 10 years is still a good value.

Kidde Nighthawk - Best For Your Budget

Budget Pick
Kidde Carbon Monoxide Detector

This company has been making fire safety products for over 90 years. As the world’s largest fire safety product manufacturer, it also produces high quality carbon monoxide detectors. With a digital display, you can read your home’s carbon monoxide levels easily. Plus, the device refreshes its data every 15 second 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.


You can bring one of these devices home for about $30.

Digital Display.
Some alarms only tell you if your carbon monoxide levels have reached critical mass. This one will tell you if any particles are in your home, so you’ll know if there’s a leak that’s getting worse and get to safety faster.

#1 Best Seller on Amazon.
Customers love this device and it’s the most popular carbon monoxide detector on Amazon.Backup Battery. This is a hardwired carbon monoxide detector, but it has a backup battery in case you lose power.

Backup Battery.
This is a hardwired carbon monoxide detector, but it has a backup battery in case you lose power.


No Home Automation.
This isn’t as advanced as Nest Protect. You won’t get phone alerts or the ability to see where in your home the carbon monoxide is being detected.

Must Hard-Wire.
You have to wire this device into your electrical system for it to work—even though it has a backup battery.

Single Sensor.
This is only a carbon monoxide alarm. You’ll have to buy smoke alarms separately.

First Alert Onelink - Best Voice Control

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. They’re also controllable from your Apple device through an app, so you can silence them or get notifications on your phone.


10-Year Battery.
You won’t have to change batteries or hardwire this alarm. It comes with a 10-year battery that won’t annoy you with chirps.

This is the first smart alarm to work with Apple’s HomeKit technology. If you have an apple device, you can get notifications from your First Alert alarms and control them from wherever you are.

Voice Alarm.
Expect to hear a human voice when this alarm goes off.

Syncing System.
If one alarm goes off, all alarms in your home will sound.

Doubles As Smoke Alarm.
You’ll have double the life-saving power in one alarm.


When the battery dies, you’ll need a new alarm.
Since you can’t change the batteries yourself or hardwire this unit, you’ll need to replace the whole thing once it expires. Its life expectancy of 10 years is still a good value.

First Alert CO400 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 can easily be placed in any room with an outlet, which gives you a lot of flexible placement options.


Affordable Price
The First Alert CO400 rings in just shy of $20, which makes it an affordable choice for renters, homeowners, and landlords who are looking for an effective CO detector that won’t break the bank.

Dependable Readings
Thanks to the device’s electrochemical sensors, the readings are accurate and timely.

Basic Design
The CO400 has a no-frills, simple silhouette that blends in effortlessly with your home.


Difficult Battery Compartment
Users said they had a tough time opening and closing the battery compartment when the device needed more juice.

Kidde Battery-Operated

Kidde’s battery-operated CO detector is equipped with the best sensor in the industry, an electrochemical sensor, to detect carbon monoxide in your home. And the digital display makes it easy to monitor your home’s levels of carbon monoxide. Plus, an 85 dB alarm will sound if dangerous levels accumulate without your knowledge.


Digital Display
You’ll know exactly how much carbon monoxide is in the air with this digital display.

Frequent Readings
The device will recalculate levels of carbon monoxide every 15 seconds and post them on the digital display for you to read.

Easy Installation
No wires come with this alarm, so you’ll only need to put batteries in and mount it on the wall.

Affordable Price
This alarm only costs around $20 on Amazon.


No Home Automation
These alarms don’t have smart capabilities, so you can’t control them from your phone.

First Alert CO605 Detector

This stripped-down carbon monoxide detector doesn’t come with any extras, but it gets the job done. A number of 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, the First Alert CO605 is a solid choice.


Easy Installation
All you have to do to set up this CO detector is plug it into a wall outlet. Once it’s plugged in, give the test button a try to make sure everything is in working order.

Small Size
You’ll like that the First Alert CO605 won’t hog all the space on the outlet you use. It’s small enough to leave the second plug free for a lamp, nightlight, or anything else you want to plug in.

Battery Backup
You don’t have to worry about losing protection if there’s a power outage. Even though this CO detector plugs into the wall, it has built-in battery backup to make sure you’re never left without continuous monitoring of carbon monoxide levels.


No Frills
There really are no extras on the First Alert CO605. There’s no digital display, voice alert, or smart home capability.

Know What To Do And What Not To Do

Lighting a fire in your fireplace is okay because 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)

Remember What Can Make Carbon Monoxide Gas

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
  • Chain saws
  • Pressure washers
  • Generators
  • Non-electric cars, trucks, and boats

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