First Alert has been making residential smoke detectors for decades, and the SMI100-AC is a direct response to newer safety standards. The big shift here is Precision Detection technology, which is designed to reduce those annoying false alarms from cooking steam or shower humidity while still catching a real fire quickly. That matters because a detector that goes off every time you toast a bagel often ends up disabled.

Installation is straightforward if you already have a hardwired setup. The unit slides onto the same mounting bracket and uses the same wiring harness as older First Alert models, so you can swap it in without calling an electrician. It includes a battery backup, so it keeps working if the power goes out. You can also interconnect multiple units to make the whole house sound when any single alarm triggers.

The trade-off is that this model is battery powered for backup only, not a standalone battery unit. If your home doesn’t have existing hardwire wiring, you’ll need to run new cable or look at a different style. For anyone replacing old interconnected alarms, this is a solid, code-compliant upgrade that cuts down on nuisance triggers without sacrificing detection speed.