First Alert SC5 Battery Smart Smoke & CO Alarm vs First Alert SC5 Hardwire Smart Smoke & CO Alarm

Neither wins outright, it is a tie. Both share the same smoke and CO sensing, Google Home integration, alerts, and warranty length. The choice comes down to whether you want a hardwired unit or a fully battery-powered one.

Power source. The First Alert SC5 Hardwire Smart Smoke & CO Alarm connects to mains power with a lithium battery as backup and needs existing alarm wiring, while the First Alert SC5 Battery Smart Smoke & CO Alarm runs entirely on six CR123A batteries and needs no wiring at all.

Yes. Both combine a photoelectric smoke sensor with an electrochemical carbon monoxide sensor, send the same fire, CO and low-battery alerts, and include the same steam-check technology to reduce nuisance alarms.

The First Alert SC5 Battery Smart Smoke & CO Alarm, since it runs entirely on replaceable batteries and does not require an electrical connection or wiring adapter.

Homeowners who already have hardwired alarm circuits, especially anyone replacing an aging or discontinued Google Nest Protect on an existing mount, and who prefers not to rely solely on batteries.

Buyers installing an alarm in a room without existing wiring, or anyone who wants a simple battery-only install while keeping the same smoke and CO protection and Google Home alerts as the hardwired version.