First Alert SMCO410 Smoke Detector & CO Alarm vs Shelly Plus Smoke Alarm

The First Alert SMCO410 Smoke Detector & 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 integration, but it detects smoke only.

The biggest difference is that the First Alert SMCO410 Smoke Detector & 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 SMCO410 Smoke Detector & CO Alarm adds a 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 SMCO410 Smoke Detector & CO Alarm uses Z-Wave and works with the Ring Base Station and Home Assistant.

Buy the First Alert SMCO410 Smoke Detector & CO Alarm if you want combined smoke and carbon monoxide detection with steam-check, CO and low-battery alerts and a 10-year warranty, and you run a Z-Wave, Ring or Home Assistant setup.

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.