10 Best Carbon Monoxide Detectors 2026 in the United States

The First Alert BRK SC9120B-3 is a reliable choice for anyone looking to protect their home from both smoke and carbon monoxide hazards. It uses two types of sensors: an electrochemical sensor for detecting carbon monoxide, and an ionization sensor that reacts quickly to fast-burning fires. This dual-sensor approach enhances safety by covering different types of fire and gas risks.

One of the standout features is its hardwired design combined with a battery backup. This means the alarms will keep working even during a power outage, giving you peace of mind around the clock. The unit’s alert system includes an 85-decibel siren—loud enough to wake most people—and indicator lights that clearly show what kind of danger is detected.

Installation is straightforward thanks to universal mounting brackets and a tamper-resistant design, making it suitable for use in various locations around the home. The detector can also be interconnected with other compatible First Alert alarms, so if one unit senses danger, all alarms will sound, improving safety. The display is simple, with indicator lights and a single test/silence button that makes it easy to check the system or temporarily quiet a false alarm. It also comes with a dust cover to help keep the sensor clean. This 3-pack is ideal for homeowners who want dependable, long-term monitoring of both smoke and carbon monoxide with backup power, especially in larger homes or multiple rooms. Note that installation requires wiring, which might need professional help if you’re not comfortable with electrical work.

The First Alert Combination Smoke & Carbon Monoxide Alarm (SMICO100-AC) is a solid choice for home safety, combining smoke and CO detection in one device. It uses an ionization sensor, which is good at detecting fast-flaming fires but may be less sensitive to slow, smoldering fires compared to other sensor types. This alarm is powered by a corded electric source with a battery backup, meaning it stays active even during power outages, which adds an important layer of reliability.

Installation is made easier with a Quick Connect Plug, allowing for straightforward setup without rewiring, and it supports early warning interconnect, so if one alarm goes off, all linked alarms sound as well—great for larger homes. The unit includes a test/silence button for easy maintenance and nuisance alarm reduction, especially around cooking areas. Its compact size and white color help it blend into most home environments.

This alarm requires a 9V battery, which is included but will need replacing over time. The ionization sensor, while effective, might not be the best option if you want the most sensitive detection of all types of fires. For someone seeking dependable dual-function protection with easy installation and clear alerts, this First Alert model is a very practical and well-regarded choice.

The Kidde Carbon Monoxide Detector is a plug-in device with a 9-volt battery backup, ensuring reliability even during power outages. It uses an electrochemical sensor, which accurately detects carbon monoxide and certain explosive gases like propane and methane. The digital LED display shows the current CO levels or indicates when explosive gas is detected, providing real-time information beyond just an alarm. The alarm volume is 85 decibels, loud enough to alert you effectively. Installation is simple—you just plug it into a standard 120V outlet, suitable for most homes.

The unit includes a peak level memory function that records the last CO detection or test, which is useful for monitoring safety history. However, since it relies on plugging into an outlet, it might not be ideal for locations without nearby power sockets, such as some basements or garages. Also, the temperature operating range tops at 100°F, so very hot environments might affect performance. It weighs about a pound and is compact enough to fit discreetly on a wall.

This Kidde detector covers both carbon monoxide and certain gas alarms but does not detect natural gas specifically, so checking your fuel sources is important. Backed by a 5-year limited warranty and positive customer feedback, this device is a solid choice for typical home use, especially if you want combined gas and CO detection in one unit.