Best Smoke and Carbon Monoxide Detectors of 2023

Consumer Reports' lab tests reveal the best ones for protecting you and your loved ones

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A smoke and carbon monoxide detector's ability to sense carbon monoxide (CO) can mean the difference between life and death. According to the Centers for Disease Control and Prevention, more than 400 Americans die from accidental CO poisoning every year, and about 100,000 end up in emergency departments. While most detectors look similar and come certified by a testing organization such as Underwriters Laboratory (UL) or Intertek Electrical Testing Labs (ETL), their efficacy isn't necessarily the same. "We need to test detectors because some fail at CO detection, and there are differences in how quickly different models respond to CO," says Bernie Deitrick, Consumer Reports’ test engineer for smoke and CO detectors. "I have never tested a model that failed our fire and smoke tests, and it is reassuring to know that such critical devices actually work."

For a look at all the models we’ve tested, see our smoke and carbon monoxide detector ratings. And to figure out the right detectors for your home, read the accompanying buying guide.

In the lab, we expose detectors to both flaming fires and smoldering, smoky fires to see how well they detect fire and smoke, respectively. For interconnected CO alarms—which react as a group when any one of them is triggered—we expose them to precise low CO levels (100 ppm, or parts per million) and high CO levels (400 parts per million) to see how accurately and how quickly they detect the deadly carbon monoxide. And for stand-alone CO detectors, we check the accuracy of the CO levels that they either display on their screens or read aloud via voice messages.

Generally, detectors are battery-powered, hardwired, or plugged into an outlet. To determine the type you need, remove the detectors in your home from their mounts.

Below are the best smoke and carbon monoxide detectors from our tests, arranged in alphabetical order, with hardwired and battery-powered picks for each type of detector: stand-alone smoke detectors, stand-alone CO detectors, combination smoke-CO detectors, and smart smoke-CO detectors that can send alerts to your smartphone.

First Alert 3120B

CR's take: The First Alert 3120B is a dual-sensor smoke detector, meaning it has both a photoelectric sensor for detecting smoky fires and an ionization sensor for detecting flames. Thanks to its use of both types of sensors, this First Alert receives top scores in our flaming fire and smoldering fire tests. It's hardwired with a battery backup, which makes it a good candidate for newer or remodeled homes that have wiring for detectors, and it features a hush button to silence nuisance alarms. It can be interconnected with additional detectors so that if one goes off, they all go off and alert you to danger even if you’re in a different room or on a different floor from the fire.

Kidde PI2010

CR's take: Another top performer in our tests is the Kidde PI2010, which receives the highest scores possible in our flaming fire and smoldering fire tests. This hardwired, dual-sensor alarm features a battery backup, a hush button, and the ability to interconnect with other compatible detectors. To determine which other models are compatible with this one, check with Kidde.

First Alert SA320CN

CR's take: The First Alert SA320CN is one of the best battery-powered dual-sensor detectors in our ratings, receiving high marks in both the flaming fire and smoldering fire tests. It features a hush button and runs on two AA batteries, but it can't interconnect with other alarms to make them all go off in the event of a fire.

First Alert Ultimate Protection SA3210 (Battery)

CR's take: First Alert's Ultimate Protection SA3210 received top marks for the flaming fire and smoldering fire tests. Like the SA320CN, the SA3210 features a hush button, but instead of two AA batteries, the SA3210 runs on a 10-year lithium battery. It also can't interconnect with other smoke detectors.

Kidde PI9010

CR's take: Another good choice for a battery-powered detector is the Kidde PI9010. This top-notch detector receives strong scores in our tests for flaming fires and smoldering fires. It features a hush button and runs on a single 9-volt battery, but it can't interconnect with other detectors. (Models made between Sept. 10, 2016, and Oct. 13, 2017, are subject to a recall due to a defect that prevents them from detecting smoke. This recall doesn't affect units currently available for purchase.)

Universal Security Instruments AMIB3051SC

CR's take: The Universal Security Instruments AMIB3051SC is one of the first smoke detectors designed to the latest UL 217 standard for smoke alarms, which makes smoke detectors better at reducing false alarms related to cooking. This model receives high scores in our tests for both flaming fires and smoldering fires, and it runs on a built-in 10-year alkaline battery. It also features a hush button, but it can't interconnect with other detectors.

Kidde KN-COSM-IBA

CR's take: The hardwired Kidde KN-COSM-IBA CO detector performs very well. It receives top-level marks in our low-CO-level test and for the accuracy of its CO-level display, and a near-top-level mark in the high-CO-level test. The model has the ability to log the highest CO levels it detects—referred to as peak memory—which is good for checking to determine whether there has been a problem when you’ve been away from home for a long period of time. It also has a battery backup and the ability to interconnect with other compatible alarms.

First Alert CO615

CR's take: The First Alert CO615 is one of the few plug-in CO detectors in our tests, and it beats out its hardwired and battery-powered brethren, with strong scores in our tests for detecting high and low CO levels quickly, as well as a respectable rating for the accuracy of its CO level display. It features a battery backup and peak memory, so you can check to see whether CO levels have been high after you’ve been gone for a long period of time.

First Alert OneLink SCO501CN

CR's take: If you need a battery-powered CO detector, check out the First Alert OneLink SCO501CN. It excels in our tests for detecting high and low CO levels, as well as for the accuracy of its CO readings. When the alarm detects CO, an 85-decibel siren and voice alarm (with 11 programmable locations) indicates where and what the development is. Aside from voice alerts, this model features the ability to wirelessly interconnect with other First Alert-enabled alarms. The alarm has a peak memory feature, which logs the highest CO reading so you can see if there was a problem while you were away from home.

Universal Security Instruments AMICH3511SC

CR's take: If you need a hardwired combination detector, the Universal Security Instruments AMICH3511SC is your best bet. It performs excellently in our low-CO-level test, as well as in our smoldering fire and flaming fire tests. It earned an adequate score for detecting high CO levels. It's rated to protect against smoke, fire, and carbon monoxide, and it comes with a sealed battery that should last for 10 years.

Universal Security Instruments MIC3510SB

CR's take: The Universal Security Instruments MIC3510SB is one of the few combination detectors that has both photoelectric and ionization sensors for smoldering and flaming fires (most combo models have only one of the two) in addition to a CO sensor. As a result, this USI detector is the only combination model to perform well across all our smoke and CO tests. This model runs on a sealed, 10-year battery and it has a hush button. But it can't interconnect to other detectors.

First Alert Onelink Smart 1042135

CR's take: For a smart smoke and CO detector that connects directly to WiFi, check out the First Alert Onelink Smart 1042135. This model receives strong scores in all our tests, with the exception of flaming fires because it lacks an ionization sensor. If you go with this detector, you may want to also consider purchasing a battery-powered ionization smoke detector, such as the Kidde RF-SM-DC. This First Alert comes in both battery-powered and hardwired versions, can interconnect with other compatible detectors, and works with Amazon Alexa and Apple HomeKit/Siri for voice and app control.

First Alert ZCOMBO

CR's take: The First Alert ZCOMBO is a smart smoke and CO detector that's certified to work with Ring's Home Security System, where you can work the detector through the Ring app on your phone. It received top marks in our smoldering fires test and was able to accurately and quickly detect low CO levels. It performed poorly when asked to detect flaming fires, though. The First Alert ZCOMBO is battery-powered.

Google Nest Protect: Smoke + Carbon Monoxide

CR's take: The Google Nest Protect is another WiFi-enabled combination smoke-CO detector that performs well in our tests. It receives strong scores in our tests for low CO levels and smoldering fires, as well as a good rating for detecting high CO levels. But like the First Alert Onelink, it falls short in our flaming fire test. If you go with this detector, you may want to also consider purchasing a battery-powered ionization smoke detector, such as the Kidde RF-SM-DC. The Google Nest Protect comes in both battery-powered and hardwired versions and can interconnect with additional Nest Protects.

Daniel Wroclawski

Dan Wroclawski is a home and appliances writer at Consumer Reports, covering products ranging from refrigerators and coffee makers to cutting-edge smart home devices. Before joining CR in 2017, he was an editor at USA Today's Reviewed, and launched the site's smart home section. In his spare time, you can find him tinkering with one of the over 70 connected devices in his house. Follow Dan on Facebook and Twitter @danwroc.