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The Best Carbon Monoxide Detectors and Alarms – Top Picks and Buying Guide

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Quick Overview

Carbon monoxide (CO) is colorless, odorless gas that’s deadly to humans and animals. Your best defense against CO poisoning is to install carbon monoxide detectors and alarms throughout your home – on every floor and outside all bedrooms.

Best Carbon Monoxide Detectors and Alarms

Today’s CO detectors and alarms are easy to use and easy to install. You can buy ones that double as smoke detectors, or you can buy standalone CO alarms. You can even get smart-home CO detectors that alert you on your smartphone when the levels get too high. There are types to meet all needs and budgets, with prices ranging from $25 to $125.

Check out our top picks for carbon monoxide detectors and alarms. Then read our Buyer’s Guide to find the best one to keep you and your loved ones safe.

Our Top 5 Picks

The Best Carbon Monoxide Detectors – Reviewed

Editor's Pick – First Alert Combination Alarm

Editor's Pick – First Alert Combination Alarm


  • Battery-operated
  • Combination smoke/carbon monoxide alarm
  • Wireless
  • Interconnects with other First Alert alarms
  • Voice alarm
  • 7-year warranty
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Editor’s Choice Overview

The First Alert SCO501CN-3ST is a combination smoke and carbon monoxide alarm. You can connect it with other OneLink First Alert alarms to create a system of CO monitoring in your home. When one alarm sounds, all the others will, too.

The Voice Alarm is its standout feature. You can program up to 11 locations within your home, and the alarm will verbally alert you precisely where the danger is. You’ll be warned when the battery is low, and one-touch buttons make it easy to hush false alarms and test the device.

The First Alert SCO501CN-3ST is battery operated, with 2 AA batteries and mounting hardware included, so you can easily install it yourself on a wall or ceiling. This alarm packs a lot of functionality into a single device, which is why it’s our Editor’s Choice.

Best Plug-In – Kidde Nighthawk

Best Plug-In – Kidde Nighthawk


  • Plug-in with battery backup
  • Standalone carbon monoxide alarm
  • Digital display
  • 10-year warranty
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Best Plug-In Overview

The Kidde Nighthawk combines the reassurance of a digital display with the easiest installation option available – a wall plug-in. Users can plug the device directly into the wall, or use the included 6-foot retractable power cord to mount it on a wall or place it on a table top. If the power goes out, the 9-volt battery backup kicks into gear, so you’re never without monitoring.

The Kidde Nighthawk’s digital display shows the current CO levels in the house, with sensitivity as low as 11 ppm. LED lights indicate whether the sensor is working properly, and one-touch test buttons make additional confirmation easy. Users can touch the Peak Level button to see the highest CO level recorded since the last time the unit was reset or unplugged.

2-, 4-, and 6-pack versions are also available.

Best Display – First Alert Dual-Power

Best Display – First Alert Dual-Power


  • Plug-in with battery backup
  • Standalone carbon monoxide alarm
  • Digital display
  • 7-year warranty
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Best Display Overview

As a plug-in carbon monoxide detector, the First Alert CO615 is easy to mount, and comes with a 6-foot power cord if you want to place it higher on a wall or ceiling. Users can install batteries using a front-load flap, so you’re still protected even if the power goes out.

At 85 decibels, this alarm is definitely loud enough to wake you up. One-touch buttons make testing the alarm and silencing false alarms quick and easy, too.

The digital display provides more information than most carbon monoxide alarms, not only displaying the levels, but also indicating the CO levels and battery life graphically. Additionally, the device will read “EVACUATE” if the CO levels are unsafe.

Best Smart Alarm – Nest Protect

Best Smart Alarm – Nest Protect


  • Battery-operated or wired
  • Combination smoke/carbon monoxide alarm
  • Wireless, smart home-enabled
  • Voice alarm
  • 10-year warranty
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Best Smart Alarm Overview

The big selling point of the Nest Protect is that it makes everything crystal clear in the smartphone app. Instead of tearing your hair out over an annoying chirp, or wondering whether your device is still working, you can tell instantly from your smartphone. The app notifies you whenever the battery is low and self-checks the alarm regularly to ensure it’s still working properly. You can hush alarms from your phone, too.

As a smart device, the Nest Protect connects with other smart devices in your home, so it may flash the lights if the alarm is going off and the voice alarm will tell you from which room the CO is coming from. This is the combination smoke/carbon monoxide alarm for the smart home era.

The Nest Protect is available in battery-operated and wired versions, and shoppers can purchase expert installation direct through Amazon. At over $100, this carbon monoxide detector isn’t cheap, but for those who want the security of monitoring their CO levels anywhere with their smartphone, the price may be worth it.

Best Budget – Kidde KN-COPP-B-LPM

Best Budget – Kidde KN-COPP-B-LPM


  • Battery-operated
  • Standalone carbon monoxide alarm
  • Digital display
  • 10-year warranty
Click below to get the best price on the Kidde KN-COPP-B-LPM.
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Best Budget Overview

The Kidde KN-COPP-B-LPM includes a digital display so homeowners can monitor the CO levels in their home throughout the day. The high-sensitivity carbon monoxide alarm detects levels from 11 to 999 ppm, and updates the reading every 15 seconds. Additionally, colored LED lights indicate when levels are safe (green) or unsafe (red).

The Kidde KN-COPP-B-LPM is easy to mount and once installed, batteries can be replaced using a sideout door with no dismounting required. With a 10-year warranty, this is one of the longest lasting models you’ll find.

For less than $50, shoppers can get a two-pack of the Kidde KN-COPP-B-LPM, which is a great value. 4, 6, and 8-pack options are also available so you can affordably equip your home.

Buying Guide – How to Choose a Carbon Monoxide Detector

Carbon monoxide is deadly. Since we can’t smell or see carbon monoxide, it’s important that you can rely on your carbon monoxide detector or alarm to alert you if it senses carbon monoxide in your home.

To find the best carbon monoxide detector for your home, familiarize yourself with the key features below.

  • Types: There are two main types of carbon monoxide alarms – interconnected units and independent units. Interconnected units will sound an alarm on all the other alarms in the home, so you’re alerted wherever you are in the house. However, they are trickier to install, typically being hard-wired, and more expensive, due to their interconnected functionality. Independent units work just as well and are just as safe, but you will have to install more of them to ensure you have full coverage in your home. Being battery-powered, they’re easier to install and less expensive.
  • Carbon Monoxide/Smoke Detector Combination Alarms: Some CO alarms double as smoke detectors, detecting both unsafe levels of carbon monoxide as well as smoke in your home. Combination devices are typically more expensive than standalone CO detectors, but may end up being more affordable since you have to buy a lower amount of devices overall.
  • Power Source: Carbon monoxide detectors and alarms are either hardwired, battery-operated, or plug-in. Hardwired units are the toughest to install on your own, but once installed, you don’t have to worry about them. They usually include a battery backup in case your power goes out. Battery-operated and plug-in carbon monoxide detectors are easier for DIYers to install and can be placed in more areas of your home. Plug-in models typically have a battery backup as well.
  • Safety Certification: Carbon monoxide detectors and alarms that are certified by Underwriters Laboratories Standard have met global safety standards. They will also feature a label on the device letting you know the expected lifespan and expiration date of the alarm. Most states that require CO alarms in homes require that the alarm be UL certified. Besides being required by some state laws, it’s also safer for you. When the alarm nears its end of life, you will be alerted. Always buy a CO detector that has a UL certification.
  • Warranty: Most carbon monoxide detectors will last at least 5 years, although some may last as long as ten. The extra peace of mind usually comes for a higher price.
  • Digital Display: A carbon monoxide detector with a digital display will let you know how high the current level of carbon monoxide concentration is in your home, as well as the trend over time (giving you insight into whether there may be a potential leak). This offers additional reassurance for people who really want to monitor the levels in their home, and can be an important safety measure for those who live with people at increased risk of CO poisoning. At-risk individuals include infants, older adults, or anyone with heart disease, anemia, or other health conditions that affect their breathing.
  • PPM Sensitivity: The level of carbon monoxide in your home is measured in parts per million (ppm). Most carbon monoxide detectors can detect levels 30 ppm or above, and the alarm will go off when the levels reach 70 ppm. However, there are more sensitive models available, which can detect levels as low as 10 ppm. These are a good choice for those living with people at higher risk of carbon monoxide poisoning.
  • WiFi Connectivity: Some combination smoke and carbon monoxide detectors are smart home-enabled. These may use your home’s wireless connection to send notifications through a smartphone app about the current CO levels in your home and the device’s battery life. Smart carbon monoxide detectors are usually more expensive, but they come with the added benefit of being able to monitor your CO levels even when you’re not home, and to hush false alarms quickly from your phone.

Important Shopping Considerations for Carbon Monoxide Detectors

What else do you need to know when shopping for a carbon monoxide detector? Below we answer the frequently asked questions people have about these important safety devices.

What is Carbon Monoxide?

Carbon monoxide is an odorless, colorless gas that’s deadly to humans and animals. Carbon monoxide is a byproduct of gas and oil fuel-burning devices, like cars, engines, portable generators, stoves, charcoal grills, and fireplaces. When carbon monoxide builds up in an enclosed indoors area, like your home, it can be deadly.

Why Do I Need a Carbon Monoxide Detector?

Because it’s invisible and doesn’t have a smell, we rely on carbon monoxide detectors and alarms to let us know when we’re at risk of CO poisoning. According to the CDC, unintentional carbon monoxide poisoning causes over 400 deaths and 4,000 hospitalizations each year.

Any home that has fuel-burning appliances, including stoves, grills, water heaters, furnaces, and engines, should have carbon monoxide detectors installed. Even if the devices in your home are electric, but your home is connected to a garage that contains cars, you should use a carbon monoxide detector to alert you if CO ever gets into the house.

How Do I Know if Have Carbon Monoxide Poisoning?

When we breathe in carbon monoxide, we’re at risk of CO poisoning. Too much carbon monoxide can cause you to pass out or die. If you have a headache or upset stomach, vomit, feel dizzy or weak, or experience chest pain, you may have carbon monoxide poisoning.

If you suspect you have carbon monoxide poisoning, leave the area immediately to get outdoors and call 911.

How Do Carbon Monoxide Detectors Work?

Carbon monoxide detectors have a sensor that measures the levels of carbon monoxide in your home. When the levels reach an unsafe amount, the device will sound an alarm to alert you.

How Much Do Carbon Monoxide Detectors Cost?

Depending on the type and included features, carbon monoxide detectors range from $25 to $125. When budgeting, remember that you’ll need to purchase an alarm for each floor of your home, as well as for each bedroom.

Where Should I Place My Carbon Monoxide Detector?

Place your carbon monoxide detector in an area where you’ll be able to hear it if it sounds off. If it goes off while you’re sleeping, you want it to be close enough to your bedroom for it to wake you up.

If you have people sleeping in multiple bedrooms, place a CO detector outside each bedroom. If you have multiple floors in your home, there should be at least one detector on each floor.

A majority of states have legislation dictating where you must install the carbon monoxide detector. You can view your state’s laws here.

When Should I Replace My Carbon Monoxide Detector or Alarm?

Your carbon monoxide detector will come with safety instructions that tell you how long you can expect the alarm to function properly. This will also be clearly indicated on the box.

Unless your alarm is designed to work for longer, you should plan to replace your carbon monoxide detector every five years. Check the battery at least twice a year to ensure it’s still working properly, and replace it if not.

How Else Can I Prevent Carbon Monoxide Poisoning in My Home?

One of the best ways you can prevent carbon monoxide poisoning is by installing carbon monoxide alarms and maintaining them properly.

You should also never use generators or grills indoors, and never use a gas-powered stove to heat your home. The CDC offers additional CO poisoning prevention tips on their website, such as how to maintain and safely use your fuel-burning appliances.