10 Best Smoke Detector Carbon Monoxide Detectors Combo 2026 in the United States

The First Alert SMICO100-AC is a 3-pack combination smoke and carbon monoxide alarm designed to offer dependable home safety with several useful features. It uses ionization sensors, which are particularly sensitive to fast-flaming fires, making it effective for early smoke detection. Powered by corded electricity with a battery backup, it ensures continuous operation even during power outages—a critical plus. One standout feature is its interconnectivity: when one alarm detects danger, all compatible alarms in the system sound, providing thorough home coverage and early alerts throughout the house.

Installation is user-friendly thanks to a quick connect plug that eliminates complex rewiring, and each unit includes a test/silence button for easy maintenance and to reduce false alarms. The device incorporates First Alert's Precision Detection technology that helps reduce nuisance alarms caused by cooking smoke, which can be a common annoyance in kitchens. While the ionization sensor excels at detecting certain types of fires, pairing this with photoelectric sensors is generally recommended for the best smoke coverage; this model focuses on ionization only.

The alarms include 9V alkaline batteries which come included, but these will need periodic replacement like any battery-operated device. As a hardwired system with battery backup, it combines reliability with peace of mind. With strong popularity, this product suits homeowners looking for a straightforward, reliable smoke and CO alarm system that is easy to install and maintain. This combo alarm provides solid protection with convenient features for everyday home safety.

The Kidde Smoke & Carbon Monoxide Detector 2-pack is a practical choice if you're looking for an easy-to-use device that covers both smoke and carbon monoxide detection. It combines photoelectric and electrochemical sensors, which helps it detect smoke from fires and dangerous carbon monoxide gas effectively. One big plus is its 10-year battery life — you won't need to worry about changing batteries or annoying low-battery chirps for a decade, which also saves money over time. Installation is simple since it’s battery powered and wireless; just mount it on the ceiling and click it into place. It has clear LED lights to show its status, so you can easily see if everything's normal, if there's a problem, or if an alarm is sounding.

The 85-decibel alarm is loud enough to alert you even if you’re in another room. It also features a test and hush button, handy for checking the alarm works or silencing false alarms, which are less common thanks to its improved sensing technology that reduces alerts from normal cooking smoke. However, it doesn't support interconnectivity, so multiple alarms won't communicate with each other, which might be a drawback if you want whole-home coverage with linked alerts. Its operating conditions are quite standard, suitable for typical home environments.

This detector is ideal for homeowners who want a reliable, low-maintenance, combo smoke and CO alarm without complicated wiring or smart home features. It has a solid warranty and customer feedback supports its dependable performance, though after 10 years, the entire unit needs replacing, not just the battery.

The First Alert BRK SC9120B-3 is a solid choice if you're looking for a dependable smoke and carbon monoxide detector combo for your home. It uses two types of sensors: an electrochemical sensor for carbon monoxide, which is very effective at detecting this dangerous gas, and an ionization sensor that quickly spots smoke from fast-burning fires. This dual sensor setup means it covers both slow and fast fire types well.

Power is a strong point here since these detectors are hardwired into your home's electrical system but also include battery backup. That means they keep working even if the power goes out, giving you constant protection. Installation is straightforward with universal mounting brackets and tamper-resistant locking, which is helpful for peace of mind. The alarm itself is loud at 85 decibels, enough to wake most people, and the unit has clear indicator lights to show if smoke or carbon monoxide is detected. It also has a simple test and silence button, which makes maintenance easier. Plus, these alarms can be interconnected with other compatible First Alert units, so if one detects a problem, all alarms in your home will sound – a useful feature for larger houses.

While it comes with batteries included, these are 9-volt alkaline batteries which will need regular checking and replacements over time to ensure the backup power remains effective. The detectors have a standard lifespan typical for these devices, so you’ll want to replace them every 7-10 years to maintain safety. Some users might find the 5.6-inch size a bit bulky compared to newer, slimmer models. If you want a reliable, easy-to-use smoke and CO combo detector with hardwired power and battery backup, this 3-pack from First Alert offers great value, especially for families or multi-room setups. It balances strong detection technology with user-friendly features, making it well-suited for most homes seeking comprehensive safety monitoring.