First Alert has been the default choice for home safety for decades. The SMICO105-AC 3-pack solves a specific headache: you need protection from two threats, but you don’t want to clutter your ceiling with separate devices. These units combine smoke and carbon monoxide detection into one hardwired alarm, which simplifies installation and keeps your hallways looking clean.

The real value here is the 10-year battery backup. If your power goes out—or a fire cuts the wiring—these alarms stay online. They also interconnect with other compatible First Alert units, meaning if a smoke alarm triggers in the basement, every connected alarm in the house sounds. That early warning buys you critical seconds. The operating humidity range (10-95% RH) means they handle steamy bathrooms and damp basements without false alarms.

One thing to note: these are hardwired, so you need existing 120V AC wiring and a junction box for each unit. They aren’t a plug-and-play solution for renters. But for homeowners building a whole-home safety network, this 3-pack covers three key zones out of the box. The white housing is low-profile and unobtrusive, and the test button is easy to reach without a ladder. Reliable, straightforward, and built to last a decade without battery swaps.