First Alert SC5 Hardwire Smart Smoke & CO Alarm vs Shelly Plus Smoke Alarm

The Shelly Plus Smoke Alarm comes out ahead overall, winning on price, owner rating, and broader WiFi/Bluetooth connectivity plus a wider integrations list (Google Home, Alexa, Samsung SmartThings and Home Assistant). The First Alert SC5 Hardwire Smart Smoke & CO Alarm still wins on hazard coverage and warranty length.

Hazard coverage and power source. The First Alert SC5 Hardwire Smart Smoke & CO Alarm detects both smoke and carbon monoxide and runs on mains power with a battery backup, while the Shelly Plus Smoke Alarm is smoke-only and runs entirely on a replaceable battery with no wiring needed.

No. It is a smoke-only detector with no CO sensor or CO alerts, so a household that needs carbon monoxide protection would need a separate device, unlike the First Alert SC5 Hardwire Smart Smoke & CO Alarm, which covers both hazards in one unit.

The Shelly Plus Smoke Alarm connects to Google Home, Amazon Alexa, Samsung SmartThings and Home Assistant. The First Alert SC5 Hardwire Smart Smoke & CO Alarm integrates only with Google Home.

Homeowners with existing hardwired alarm circuits who want one unit covering both smoke and carbon monoxide, plus steam-check tuning to reduce cooking and shower false alarms, and who are already invested in Google Home.

Smart-home enthusiasts who already have carbon monoxide detection covered and want a hub-free WiFi smoke alarm that plugs into Home Assistant, MQTT automations, or a broader mix of Alexa and SmartThings routines.