Best Carbon Monoxide Detector of 2020—Protect Your Family from Invisible Dangers

Best CO Detector
Kidde Nighthawk Nighthawk Carbon Monoxide Alarm
Pro Bullet AC power with battery backup
Pro Bullet Continuous CO readings
Pro Bullet 85 decibel alarm
Best Combo CO/Smoke Detector
Nest Protect Smoke and Carbon Monoxide Detector
Pro Bullet Battery power or wired connection
Pro Bullet Mobile notifications
Pro Bullet Smoke and CO monitoring
Best Battery-Powered Detector
First Alert 2-1 Smoke Detector and CO Alarm
Pro Bullet Battery-powered
Pro Bullet Combination CO/smoke detection
Pro Bullet Mobile alerts
Best Cheap CO Detector
First Alert Carbon Monoxide Detector
Pro Bullet Battery-powered
Pro Bullet Affordable
Pro Bullet Electrochemical CO sensor


Carbon monoxide (CO) is a colorless, odorless, and tasteless gas that’s poisonous to humans. Because a lot of common household devices––like furnaces, gas dryers, and fireplaces––produce carbon monoxide, you want to make sure your air is clean and safe from contamination.

Our favorite carbon monoxide detectors

Compare carbon monoxide detectors

* price as of 12/20/2019 at 5:06 p.m. (MST).

Kidde Nighthawk: Best carbon monoxide detector


    Kidde Nighthawk pros and cons

    • Pro BulletAC power with battery backup
    • Pro BulletContinuous CO readings
    • Pro Bullet85 decibel alarm when CO levels become unsafe
    • Pro BulletLED screen with exact CO levels in ppm (parts per million)
    • Con BulletLimited placement options with wired connection

    Why the Kidde Nighthawk is the best carbon monoxide detector

    The Kidde cabon monoxide alarm has a strong reputation for reliable detectors, and that’s important when monitoring for the silent killer carbon monoxide.

    A small LED screen displays continuous CO levels, even at less-than-dangerous levels, so you can catch any rises in carbon monoxide early instead of waiting for the 85-decibel alarm to go off.

    The device’s powered connection gives you fewer placement options, but you won’t have to change the batteries or listen to incessant low battery alerts.

    ASecureLife’s recommendation: We recommend the Kidde Nighthawk if you already have smoke detectors and want to add CO detectors to your home.

    >>Buy the Kidde Nighthawk

    Nest Protect: Best combination smoke/CO detector


      Nest Protect pros and cons

      • Pro BulletMobile notifications
      • Pro BulletSmoke and CO monitoring
      • Pro BulletHome automation connectivity via Zigbee and Z-Wave
      • Pro BulletBattery power (AA batteries) or wired connection
      • Pro BulletLocation-specific alerts
      • Pro BulletMotion sensor light
      • Con BulletHigh price

      Why we recommend the Nest Protect

      The Nest Protect is one of the priciest detectors on the market. But in this case, you get what you pay for.

      This cutting-edge device is a combination smoke detector and carbon monoxide alarm all in one. It sends mobile alerts so you’re immediately notified when there’s smoke or unsafe carbon monoxide levels at home. That can ease a lot of anxiety for parents and pet owners as you leave your loved ones at home.

      Nest Protect integrates with other Nest equipment, like its smart thermostat and the Nest Hello Video Doorbell. So if the Nest Protect picks up on smoke or CO, it will tell the Nest Thermostat to turn off the furnace. And you can fully control it with your voice using Amazon Alexa. It also comes with a built-in motion sensor that helps you better navigate the house at night.

      ASecureLife’s Recommendation: We recommend the Nest Protect if you want a fully integrated smart home. Get this detector if you want your CO monitoring to connect with your other Google or Nest devices and apps.

      >>>Buy the Nest Protect or check out our full review of the Nest Protect.

      First Alert 2-in-1: Best battery-powered carbon monoxide detector


        First Alert pros and cons

        • Pro BulletCombination CO/smoke detection
        • Pro BulletPhotoelectric smoke sensor to reduce false alarms
        • Pro BulletMobile alerts
        • Pro BulletZ-Wave compatibility
        • Con BulletFrequent battery changes

        Why we recommend First Alert 2-1

        If you like the smart aspects of the Nest Protect but want to spend less, you might like this First Alert combination smoke and CO detector.

        The Z-Wave compatible unit works with smart home systems like Samsung SmartThings and Wink, so you can get mobile alerts whenever something happens while you’re away from home. And its battery-powered design gives you nearly unlimited placement options around your home.

        ASecureLife’s recommendation: The First Alert 2-in-1 is our favorite battery-powered carbon monoxide detector for its affordability, combination CO/smoke detection, and Z-Wave compatibility for mobile alerts.

        >>Buy the First Alert.

        First Alert Carbon Monoxide Detector: Best cheap carbon monoxide detector

          • Pro BulletAffordable reliable CO detection
          • Pro BulletBattery power for almost unlimited placement options
          • Pro BulletElectrochemical CO sensor for reliable monitoring
          • Con BulletFrequent battery changes

          Why we recommend the First Alert Carbon Monoxide Detector

          We like this First Alert carbon monoxide detector for its simplicity and reliability. It’s affordable but dependable, unlike a lot of cheaper carbon monoxide detectors that aren’t up to industry standards. Its electrochemical sensor is cutting edge and eliminates false alarms or faulty readings.

          ASecureLife’s recommendation: The First Alert Carbon Monoxide Detector is our favorite affordable CO unit that still exceeds the industry standard for CO monitoring.

          >>Buy the First Alert.

          More about carbon monoxide

          What levels of carbon monoxide are considered dangerous?

          CO concentration is measured in ppm (parts per million). While small traces of carbon monoxide, between one and 50 ppm, are common, you likely won’t experience any symptoms until the CO concentration reaches upwards of 150–200 ppm, at which point it’s extremely dangerous.

          >>Check out our article on what to do when your CO detector is beeping.

          What are the symptoms of carbon monoxide poisoning?

          Serious CO exposure can cause dizziness, disorientation, shortness of breath, fatigue, or nausea, all of which resemble symptoms of the flu. Because these symptoms aren’t unique to CO poisoning, you might not immediately associate the symptoms with the immediate threat of carbon monoxide exposure. That’s part of what makes it so dangerous, and it’s why we strongly recommend you monitor for carbon monoxide in your home.

          Where to install carbon monoxide detectors

          For the most accurate readings, you need to install at least one carbon monoxide detector on every floor. Do your best to situate the unit roughly five feet from the floor. If you have a gas furnace, gas dryer, water heater, or in-home fireplace, consider placing CO detectors close to these appliances so you can catch elevated CO levels before it spreads throughout the rest of the home.

          Our recommendation

          Having a reliable carbon monoxide detector is just as important as having good smoke detectors in your home. A reliable carbon monoxide detector can help you stay safe from the tasteless, odorless, and invisible killer that is carbon monoxide. Furnaces, fireplaces, and gas appliances all produce carbon monoxide, and a reliable CO device can help you catch CO contamination before it reaches dangerous levels.

          >> If you have smoke detectors and want to add CO detectors to your home, go with the Kidde Nighthawk.

          >>If you want the best combination CO/smoke detector out there, we recommend the Nest Protect.

          >>>If you want to see more of our favorite smoke and carbon monoxide detectors, check out our Kidde detectors review.