Google Nest Protect (Battery) vs Shelly Plus Smoke Alarm

The Google Nest Protect (Battery) is better overall as a life-safety alarm because it detects both smoke and carbon monoxide, adds occupancy, temperature, humidity, light and motion sensing, tests itself, and carries a higher owner rating. The Shelly Plus Smoke Alarm is smoke-only but wins on price, a longer battery rating, a 3-year warranty and broader platform integrations.

The biggest difference is hazard coverage and smart home reach. The Google Nest Protect (Battery) is a combined smoke-and-CO alarm with self-test and a pathlight, while the Shelly Plus Smoke Alarm detects smoke only but plugs into more platforms (Google Home, Alexa, SmartThings and Home Assistant) with automations.

The Shelly Plus Smoke Alarm supports Google Home, Amazon Alexa, Samsung SmartThings and Home Assistant plus automations. The Google Nest Protect (Battery) works only with Google Home and Home Assistant, so the Shelly is the more flexible choice for a mixed-platform or automation-heavy home.

The Shelly Plus Smoke Alarm is rated for about 5 years on its CR123A battery and carries a 3-year warranty, while the Google Nest Protect (Battery) runs on 6 AA batteries rated for roughly 2 years with a 2-year warranty. The Shelly leads on both battery rating and warranty length.

Buy the Google Nest Protect (Battery) if you want one alarm that covers both smoke and carbon monoxide with spoken early warnings, phone alerts, self-testing and a pathlight, and you prioritize that combined protection over price or platform breadth.

Buy the Shelly Plus Smoke Alarm if you want an affordable, automation-friendly WiFi smoke sensor with a long battery rating and broad support for Google Home, Alexa, SmartThings and Home Assistant, and you can pair a separate CO detector for carbon monoxide.