Carbon Monoxide Detector 1

Best Carbon Monoxide Detector

Whether you live in a home or apartment, there are several important measures you need to take to ensure your family’s health and safety, most notably installing a carbon monoxide detector.

Carbon monoxide (CO) is a dangerous gas, and what’s more concerning is the fact that it is colorless, tasteless, yet poisonous, and completely undetectable without a manmade appliance i.e. a carbon monoxide detector.

Research indicates that more than 10,000 people affected by this poisonous gas require medical treatment each year, and more than 400 people die annually due to carbon monoxide poisoning in the United States.

Carbon monoxide is produced when fuels such as wood, coal, oil, gas don’t fully burn, and in the home is caused by appliances such as furnaces, water heaters, boilers, ovens or gas dryers. Now that you know the utmost importance of buying the best carbon monoxide detector, here are four reliable options you can count on to keep you safe around the clock.

*I hope you’ll love the products I recommend! Just so you know, Plumb and Lined may collect a share of sales or other compensation from some of the links on this page. 

My Top Pick

KIDDE 21008873

Best Overall

My Rating




My Rating


#1. Best Overall Pick

KIDDE 21008873

My Rating

The Kidde 21008873 leads the pack when it comes to the best carbon monoxide detectors for home use owing to several reasons, starting with its ability to provide protection against CO even in the event of power outages. Furthermore, it is fitted with a digital display, which indicates the levels of carbon monoxide in PPM (parts per million) detected by the device, and updates the reading automatically every 15 seconds.

When the Kidde 21008873 device detects 70 ppm of CO for 60 to 240 minutes, 150 ppm for 10 to 50 minutes, or 400 ppm for 4 to 15 minutes, it sounds an alarm at 85 decibels at 10 feet. It features a freestanding design, and is powered by 3 AAA batteries (included), which can be easily replaced by sliding out the door cover of the dedicated battery compartment.

The battery safeguard feature of the Kidde 21008873 carbon monoxide detector makes it difficult to close the battery compartment without the batteries inside, making this device a great choice for senior living communities. Apart from the digital display at the front, the Kidde 21008873 CO detector features a Test/Reset button that allows you to test the alarm’s circuitry and horn, and immediately silence the device after the alarm goes off.

Adding to this, it is appointed with two LED lights – red for alarm and green for normal operation, where the latter flashes once every 30 seconds to indicate that the unit is operating properly, and the red light will start flashing when CO is detected, and can only be turned off manually when the carbon monoxide threat is eliminated. The Kidde 21008873 CO detector offers an impressive 7-year service life, and is backed by a 5-year manufacturer limited warranty.


  • Digital display
  • 7-year service life
  • Battery operation
  • 85 decibel alarm
  • Works even during power outages
  • Can be set on counter, nightstand or mounted on a wall


  • Can’t be plugged into electric outlet (battery operation only)

#2. Best Budget


My Rating

If you’re looking for a budget friendly carbon monoxide detector, and one that doesn’t scrimp on key features for its affordable price tag, the First Alert CO400 CO device is worth a second look. This battery-operated carbon monoxide detector is embedded with an advanced electrochemical carbon monoxide sensor that provides superior accuracy of CO levels regardless of where the device is placed.

Additionally, it provides continuous CO level monitoring even in the event of power failure, and sounds a rather loud 85 decibel alarm when CO reaches dangerous levels. It features several different styles of beep alerts, where four beeps and a pause indicate CO detection, one beep every minute indicates low battery, and five beeps means end of service life (five years) of the device.

The First Alert CO400 CO alarm features a Test/Silence button, which when pressed allows you test the device’s functionality, and ensure it’s in good working order. It showcases a compact and attractive design, can be placed anywhere you see fit, and can even be wall mounted with the included mounting bracket. The First Alert CO400 CO detection device is UL listed, and is backed by a 5-year limited warranty.


  • Battery operated – works in during power outages
  • 85 decibel alarm
  • Several types of alerts
  • Includes wall mounting bracket
  • UL listed and 5-year warranty


  • Lacks digital display

#3. Best AC Plug-In

KIDDE Nighthawk KN-COPP-3

My Rating

Another hit from the Kiddie portfolio of products is the Nighthawk KN-COPP-3 CO detector, which unlike the 21008873 is powered by connecting it to an electrical outlet. It also provides continuous CO level monitoring even during power outages, thanks to its onsite 9-volt battery. Furthermore, the Nighthawk KN-COPP-3 is equipped with a digital display that indicates CO levels from 30 to 999 parts per million, refreshes every 15 seconds, and also alerts you when the battery needs to be replaced.

The Nighthawk KN-COPP-3 device features an electrochemical sensor, which provides highly accurate data, so you can rest assured you’re protected at all times. But that’s not all, the peak level memory feature of the Nighthawk KN-COPP-3 displays the last CO level recorded since the device was last reset or unplugged, allowing you to keep tabs on how and when CO levels change.

Designed for home use, the Nighthawk KN-COPP-3 CO detector by Kiddie also features a Test button at the front, which when pressed ensures the unit is working smoothly, and resets the device after the alarm goes off. Speaking of which, the device sounds four beeps every five seconds when unhealthy levels of CO are detected.

Take note that the alarm will only turn off when the CO levels decrease or when the reset button is pressed. It will also beep twice every 3o seconds approximately 10 years after initial power up to indicate that it’s time to replace the device. The Nighthawk KN-COPP-3 also features an LED light located at the bottom right hand corner of the device that let’s you know that the device is working as it’s supposed to.


  • Electric power operation with battery backup
  • Digital display and LED light
  • Records last CO level
  • Audible beeps when high CO levels detected
  • Includes mounting hardware, 9V backup battery and 10-year warranty


  • Limited to 1 color option

#4. Best High Tech

NEST Protect S3000BWES

My Rating

The Google S3000BWES carbon monoxide detector is a little pricey, but does come with a rich set of innovative features such as the ability to detect high levels of smoke and CO. Designed in the USA, this CO detector by Google unlike other devices in this segment alerts you via voice when a high level of CO or smoke is detected, and even tells you exactly where it is, so you can act quickly.

With regards to alerts, the Nest Protect S3000BWES carbon monoxide detector even sends you a text message on your phone when a problem is detected or when the battery is low. It can be ordered in two different variants – wired 120v or battery powered, and features a Split-Spectrum Sensor, which is engineered to detect both slow and fast burning fires.

The Nest Protect S3000BWES can be connected with your home WiFi to receive alerts on your phone, and even be turned off remotely if it goes off while you’re away. The light of the device turns on only when you walk underneath it, allowing you to use it as a pathway motion light. The Nest Protect S3000BWES by Google does not have a test button, but rather checks itself automatically, and comes with a 2-year manufacturer warranty.


  • Wireless phone alerts and voice capability
  • Tests itself automatically
  • Serves as a pathway light
  • Detects smoke and CO
  • Comes with long-life batteries (Energizer® Ultimate Lithium “L91” AA)
  • 10-year lifespan


  • Motion nightlight is not that bright
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When on the shopping trail for the best carbon monoxide detector, you will be spoilt for choice given the myriad options available. But here are a few factors to consider to ensure you invest in the right CO detection device for your needs.


Perhaps the most important factor to consider when shopping for the best carbon monoxide detector is its accuracy, because the gas takes just 30 minutes to affect the human body.


CO detectors can either work on electric or battery power, but in the case of the former, look for a device that offers battery backup to ensure it works even during power outages.


The sound of the alarm should be loud and clear, and there are come CO detection devices that offer both audible and voice alarms.

Digital Display

Not really a must, but nice to have to give you a clear indication of CO levels with a quick glance.


Most of the best carbon monoxide detectors for apartments and home use are easy to install right out of the box, so you don’t have to worry about calling in professional help. It is also important that you install the CO detection device in the right location, and if you aren’t sure where, this handy CO detector installation guide should set you on the right track.

Final Thoughts

Carbon monoxide is an undetectable and dangerous gas, so installing a carbon monoxide detector in your home or apartment shouldn’t be an option. The four models mentioned on this list are the best you can buy in this space, and offer the superior protection for you and your family against high carbon monoxide levels.

Carbon Monoxide Detector Battery Model

Steve Wright

Steve Wright is a general contractor who over the last 30 plus years has built hundreds of new homes, ranging from first time affordable homes to multi-million dollar custom homes and everything in between.