The affordable appliance could save your life.

By Jon Patrick Hatcher
Updated February 21, 2020
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Dubbed the “invisible killer”, carbon monoxide, or CO, is a deadly, odorless gas that can be omitted from any type of malfunctioning gas-burning appliance. According to the Centers for Disease Control and Prevention, accidental carbon monoxide poisoning claims the lives of more than 400 people per year and hospitalizes over 4,000 others. 

What’s worse, the flu-like symptoms that people experience after a carbon monoxide leak are often mistaken for a real case of the flu or another sickness, which can lead to delayed or misdiagnosed treatment. And while the possibility of some type of appliance failure happening in your home always exists, there is one simple way to make sure you and your loved ones stay safe: investing in a carbon monoxide detector. 

Why you need a carbon monoxide detector

“Carbon monoxide detectors are becoming required by various states and municipalities, with 27 states currently having [it as] a legal requirement for new construction, remodels, and rentals,” said Randy Smith, home contractor and founder of The Handyman Company. However, laws vary by state when it comes to the requirement of detectors in hotels, apartments, or rental properties. If you’re moving into an older home, it’s typically your responsibility to ensure there is one installed (or check with the landlord if you’re renting). 

While many people recognize the importance of having a reliable carbon monoxide detector in their living space, some overlook the need for one while traveling, too. “Hotels, motels, and Airbnb’s within and outside of the U.S. often have improperly serviced or malfunctioning appliances and furnaces,” said David King Jr., Captain of the Chesapeake, Virginia fire department. “[This could] result in potential CO exposure.”

How to choose a carbon monoxide detector

There are a few different types of detectors available. Some come as separate units, while others are combined with smoke alarms. You can also choose between battery-powered or plug-in options. Battery-powered detectors are often installed in houses and apartments, while plug-in options come in handy for use in hotels and vacation rentals. There are also compact and portable battery-powered versions that can be used while traveling. 

If you go with a plug-in model, Karla Crosswhite, a spokesperson for the Consumer Product Safety Commission (CPSC), recommends having a battery backup on hand in case of power outages. What’s more, it’s crucial to regularly check and replace batteries as needed, just as you would with a battery-powered smoke detector. “Carbon monoxide alarms typically have a life expectancy of 5 to 7 years, and many have an end-of-life indicator,” said Crosswhite. “Test CO detectors every month, and replace the batteries every 6 months or whenever clocks are changed during the spring and fall.”

Based on guidelines from the CPSC and other experts, we outlined the 7 best carbon monoxide detectors you can buy online from Amazon, Walmart, and the Home Depot. Whether you’re looking for combination smoke and CO detectors, battery-powered options to install in your home, Bluetooth-enabled detectors that connect to your phone, or portable plug-in devices for travel, you’ll find what you need in the list below. Since carbon monoxide poisoning comes on suddenly and unexpectedly, having a trusted CO detector in your home is an absolute necessity—it could be a matter of life or death.

Best Overall: Google Nest Protect Wired Smoke and Carbon Monoxide Detector 

HomeDepot

Our top pick for a carbon monoxide detector, the Google Nest Protect is designed to detect smoke and carbon monoxide in residential environments for up to 10 years. This highly-rated smart device not only acts as both a smoke and carbon monoxide alarm, but it’s also WiFi and Bluetooth-enabled, so it conveniently sends alerts to your phone through the corresponding Nest app. The 2-in-1 appliance reliably alerts you to the presence of smoke or carbon monoxide by speaking in a clear, human voice, and even goes as far as telling you the exact location it was detected. Its battery-powered and consistently checks its own batteries, letting you know they're working with a subtle green glow, or calmly alerting you if they’re not. What’s more, this customer-loved device has more than 3,000 5-star reviews, so you can trust that you’re making a smart purchase. 

Available at homedepot.com, $119 

Best Value: Kidde Battery Operated Carbon Monoxide Detector 2-Pack

Home Depot

Smith recommends Kidde and said his company typically chooses the brand for CO detectors because “they specialize in first-defense efforts and have a proven track record of producing consistent detectors.” This particular version will give you the best value; you’ll get a 2-pack of battery-powered alarms for just $40. What’s more, the Kidde Nighthawk has great features for the price—it uses an electrochemical sensor to detect CO levels and the digital display updates the reading every 15 seconds, so you’ll know right away if levels change. With an average 6-month battery life, the compact and inconspicuous device is suitable for any room in your home and comes with a 10-year warranty.

Available at homedepot.com, $40

Best 2-in-1: First Alert ZCombo Smoke Detector & Carbon Monoxide Alarm

Amazon

First Alert is another expert-recommended brand that Smith and his company prefer when it comes to CO detectors. This 2-in-1smoke and carbon monoxide combination detector from First Alert uses a smoke sensor and electrochemical CO sensor to detect levels and alert you instantly if either are present. The wireless, battery-powered device is super easy to install and is compatible with certain smart home systems, including Samsung SmartThings, so it can send updates directly to your phone. Along with residential use, the top-rated appliance is also designed to protect office buildings, hotels, and other public spaces. 

Available at amazon.com, $37 (was $50)

Best Plug-In Carbon Monoxide Detector: Kidde Nighthawk 

Amazon

Another top choice from Kidde, this super affordable CO alarm can be plugged into any electrical outlet to offer protection no matter where you are. The easy-to-use detector has a digital LED screen that clearly displays the CO level in the room, along with a test and reset button. Aside from the under-$30 price point and the 2,800 positive customer reviews, the most impressive part of this device is that it comes with a built-in short-term battery backup—so it’ll keep you safe even in the case of a power outage. 

Available at amazon.com, $29

Best Smart Alarm: Onelink Safe & Sound by First Alert 

Amazon

The Onelink combination CO and smoke alarm from First Alert keeps you protected and connected to what’s going on in your home, even when you’re not there. It connects to the corresponding app via Bluetooth, so you can control the device entirely through your phone—whether that’s receiving notifications of the CO levels in your house while you’re away, keeping track of battery levels, or being alerted about a potential fire. What’s more, it also has Alexa capabilities, so you can choose to control it through voice technology, and the 10-year sealed battery backup means you won’t have to worry about battery replacements for the life of the alarm.

Available at amazon.com, $178 (was $250)

Best for Travel: Forensics Detectors CO Gas Alarm

Amazon

While it may not be the first thing on your mind while traveling, CO poisoning is a very real threat when staying in hotels, rental homes, or any other type of lodging. This compact and well-designed travel sensor is a simple way to make sure you stay safe no matter where you are. The portable device has enough sensitivity to alert you when you’re exposed to lower levels of CO that many other alarms don’t detect yet. It has a red light that goes off in combination with the alarm sound, a clear digital display that shows the CO level, and a battery life indicator that makes it clear when it’s time to replace the batteries (usually after 8-12 months of operation). Plus, the single-button operation makes it super easy for anyone to use.

Available at amazon.com, $100

Best Portable: Sensorcon CO Inspector

Amazon

If you're looking for a handheld, portable sensor to have on hand in any situation—whether that’s monitoring a building or construction site, testing around certain appliances, or bringing with you on a boat, airplane, or RV—this is your best bet. Sensorcon’s professional-grade detector uses a high-performing electrochemical sensor to measure CO levels and offer real-time updates on the small LED screen. The battery-powered gadget is also lightweight and waterproof.   

Available at amazon.com, $129

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