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

The First Alert SC5 Battery Smart Smoke & CO Alarm is better overall as a safety device because it adds carbon monoxide detection, more alerts and a 10-year warranty. The Shelly Plus Smoke Alarm counters as the more affordable, better-rated unit with hub-free Wi-Fi and wider integrations, but it detects smoke only.

The biggest difference is that the First Alert SC5 Battery Smart Smoke & CO Alarm detects both smoke and carbon monoxide, while the Shelly Plus Smoke Alarm detects smoke only. The Shelly makes up ground with a lower price, higher rating and integration with Google Home, Alexa, SmartThings and Home Assistant.

No. The Shelly Plus Smoke Alarm is a smoke-only device with fire and low-battery alerts and no CO sensor. The First Alert SC5 Battery Smart Smoke & CO Alarm adds an electrochemical carbon monoxide sensor plus CO alerts, covering both hazards from one unit.

The Shelly Plus Smoke Alarm integrates with more platforms, working with Google Home, Alexa, Samsung SmartThings and Home Assistant over hub-free Wi-Fi. The First Alert SC5 Battery Smart Smoke & CO Alarm works with Google Home and focuses on standalone smoke and CO protection.

Buy the First Alert SC5 Battery Smart Smoke & CO Alarm if you want combined smoke and carbon monoxide detection with steam-check, CO and low-battery alerts, voice alerts naming the danger, and a long 10-year warranty and battery life.

Buy the Shelly Plus Smoke Alarm if you want the more affordable, better-rated option with hub-free Wi-Fi setup and integration with Google Home, Alexa, SmartThings and Home Assistant, and you do not need carbon monoxide detection.