First Alert has been the default choice for home fire safety for decades. The SMI100 updates that formula with Precision Detection, a sensing system designed to cut down on false alarms from cooking steam or shower humidity. That alone makes it worth a look if you’ve ever been yanked out of bed by a chirping detector triggered by toast.

The two-pack runs on batteries, so there’s no hardwiring required. Mounting takes about five minutes with a drill and a screwdriver. The front-access battery compartment is a small but meaningful detail—you don’t have to twist the whole unit off the ceiling to swap in fresh AAs. The alarm itself is loud enough to wake a heavy sleeper on the opposite end of a 1,200-square-foot floor. It meets the latest UL 217 standards, which means it responds faster to smoldering fires than older models.

The trade-off is that this is a straightforward smoke alarm. There’s no carbon monoxide detection, no voice alerts, and no smart connectivity. If you want app notifications or integration with a home hub, you’ll need to look elsewhere. But for a reliable, no-fuss replacement or first-time install in bedrooms and hallways, the SMI100 does exactly what it should without adding complexity.