The 6 Best Carbon Monoxide Alarms to Buy in 2018

Shop for the best carbon monoxide alarms from brands like First Alert and Nest


You can’t see or smell deadly carbon monoxide. That makes a carbon monoxide detector an absolute must for any home with a fuel-burning appliance of any kind, whether that’s for heating, cooking or something else. Common examples include oil furnaces, wood-burning fireplaces or gas ranges.

Carbon monoxide alarms generally fall into two types: Those that can connect to smoke alarms and other carbon monoxide alarms, and units that work independently. The independent units are usually the most...MORE inexpensive and easy to install, but you may need several for complete coverage. Interconnected units often function as smoke detectors as well – a nice bonus – and can trigger an alert on all of a home’s alarms. These may require a bit more installation know-how, especially if they are hard-wired instead of battery-operated. 

Here are some good bets if you’re shopping for a reliable carbon monoxide alarm:

  • First Alert SCO501CN-3ST ONELINK Battery Operated Combination Smoke and Carbon Monoxide Alarm with Voice Location

    Best Overall: First Alert OneLink SCO501CN-3ST Smoke and Carbon Monoxide Alarm

    When it comes to carbon monoxide alarms, reliability and accuracy are the most important buying criteria. Reviewers say this reasonably priced First Alert OneLink model, a combination smoke and carbon monoxide alarm, has both in spades. It uses electrochemical sensors that get top marks from experts for recognizing both high and low carbon monoxide levels, and testers say it has a very accurate display. This is a ceiling-mounted alarm that requires two AA batteries. 

    As a OneLink device, this model wirelessly connects to any other First Alert OneLink devices in the home, triggering all other alarms as well. Other features include a voice alarm with 11 programmable locations to tell users where an alarm was triggered, an 85-decibel siren, a test/silence button, and indicator lights for both smoke and carbon monoxide. Owners say these units are easy to set up without expert help, and they especially like them for protecting larger homes. Some reviewers say they have had issues with false alarms or the units not linking properly, however. Warranty is seven years.  

  • Kidde KN-COPP-3 Nighthawk Plug-In Carbon Monoxide Alarm with Battery Backup

    Runner Up, Best Overall: Kidde KN-COPP-3 Nighthawk Plug-In Carbon Monoxide Alarm

    If you don’t need a dual-function carbon monoxide and smoke detector, check out the Kidde Nighthawk KN-COPP-3, which plugs right into a standard outlet. This carbon monoxide detector gets top marks for detecting high levels of carbon monoxide and very good ones for detecting lower levels. Display accuracy is good, though not top-notch like the First Alert. Though this is a plug-in unit, it includes a 9-volt battery backup to keep working during power outages.

    Features on this Kidde include an LED display, a level button that lets users see the peak carbon-monoxide level detected since the last reset, a sensor-on indicator, and a test/reset button. A 6-foot power cord allows it to be displayed on a table or shelf, too. Unlike the First Alert, it doesn’t link to other units, and one should be placed on every floor of the house. Users love how exceptionally easy to use this installation-free alarm is, though some warn that they were shipped older units. It’s backed by a five-year warranty. 

  • Kidde KN-COB-B-LPM Carbon Monoxide Alarm

    Best Budget: Kidde KN-COB-B-LPM Carbon Monoxide Alarm

    A bare-bones carbon-monoxide protector like the Kidde KN-COB-B-LPM will still do its job, so if you don’t have a lot of money to spend, don’t fret. It uses the same electrochemical sensor as pricier units and can be either mounted on the wall or left free-standing on a table or shelf. It does not plug into the wall and requires three AA batteries to use.

    This Kidde has two indicators: One to reassure users that the sensors are working, and another to alert them that the alarm has sounded. There is a test/reset button and low-battery signal as well. A battery lockout system means owners won’t be able to shut the battery compartment unless all batteries have been properly installed – great for preventing absent-minded slip-ups. Reviewers love how compact and easy to use these alarms are, and few report false alarms or any other issues. It’s backed by a five-year warranty.

  • Nest Protect Smoke & Carbon Monoxide Alarm, Battery (2nd gen)

    Best High-End: Nest Protect Smoke & Carbon Monoxide Alarm

    If it’s bells and whistles you’re after, the Nest Protect is the carbon monoxide detector for you. The Nest is actually a combination smoke and carbon monoxide detector that connects to Wi-Fi and alerts your smartphone or tablet if there’s a problem. It comes in hard-wired or battery-powered versions and should be mounted to the wall or ceiling. Most importantly, it works well, notching above-average marks for detecting high and low carbon monoxide levels as well as accurately reporting them.

    The Nest has a ton of features: Like the First Alert OneLink, it links to other Nests and can tell you where a problem is both audibly and with phone alerts. You can even use your phone to “hush” the alarm, which periodically tests itself for proper power and operation. Nest even acts as a nightlight, lighting up as users walk under it when it’s dark, and connects to other Nest products such as the Nest Thermostat and Nest Cam. Despite all of this technology, users say it’s easy to set up. They also say the units are attractive, and they love getting phone alerts instead of middle-of-the-night low-battery chirps. As with all Wi-Fi devices, some reviewers say they’ve had problems keeping their Nests online. It’s backed by a two-year warranty.

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  • First Alert CO710 10-Year Carbon Monoxide Alarm with Temperature

    Best Design: First Alert CO710 10-Year Carbon Monoxide Alarm with Temperature

    If you want something a little sleeker than the typical carbon monoxide detector, the First Alert CO710 delivers without forcing you to spend big. This glossy white unit can sit on a shelf or tabletop, or if you’d rather mount it on the wall, you can do that, too. It also has a large, easy-to-read backlit display. Powered by a 10-year lithium battery, it doesn’t require an endless stream of AAs, either.

    The CO710 has an electrochemical sensor and an 85-decibel alarm that sounds once carbon monoxide reaches dangerous levels. A peak-level memory feature makes it easy to see how high levels have gotten in the past, and there is a test/silence button. An end-of-life alarm notifies users when the unit needs to be replaced. Users love the CO710, saying it’s attractive, unobtrusive and easy to use. It’s backed by a 10-year warranty. 

  • Onelink GLOCO- WiFi Environment Monitor with Temperature, Humidity, and Lo-level Carbon Monoxide Sensors, Apple HomeKit-enabled

    Runner Up, Best High-End: First Alert OneLink Wi-Fi Environment Monitor

    Like the Nest, the First Alert OneLink Environment Monitor is more than a carbon monoxide detector. This little Wi-Fi connected device also tracks temperature and humidity and pushes alerts straight to a user’s phone. Unlike most other detectors, it also has a visual alarm as well as an audible one, with a glowing ring that will turn red if it senses low levels of carbon monoxide. This free-standing unit plugs into the wall and has a CR2 battery backup for power outages.

    One of the most interesting features on the OneLink Environment Monitor is the LED ring on the unit, which provides a visual alert for certain conditions. Aside from glowing red for carbon monoxide, it turns blue if it’s too cold in a room and amber if it’s too warm. It works with Apple HomeKit, so iPhone users can even ask Siri to check room temperature with this device. Users love the way this detector looks and say it’s especially great for a nursery, though a few say they have issues getting it to connect with their phones. 

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