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Smoke & CO Detectors · Head to head

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

Full Smart Smoke & CO Detectors comparison in 2026

Updated September 2026
Data from Amazon and official First Alert and Shelly sites.
2026 verdict
The First Alert SMCO410 Smoke Detector & CO Alarm wins this smoke alarm comparison on the strength of its combined smoke and carbon monoxide sensing, its broader alert set, and its 10-year warranty and sealed battery.
First Alert SMCO410 Smoke Detector & CO Alarm
Winner
First Alert SMCO410 Smoke Detector & CO Alarm
$57.99$64.9811% OFF
Buy on Amazon USACheck price
It adds a CO sensor, CO and low-battery alerts and steam-check nuisance filtering, and it connects over Z-Wave with Ring and Home Assistant support, covering a hazard the smoke-only Shelly Plus Smoke Alarm cannot, while outlasting the Shelly's 5-year battery rating. The Shelly Plus Smoke Alarm is a strong runner-up, though: it is the more affordable and better-rated unit, pairs hub-free over Wi-Fi, works with Google Home, SmartThings and Home Assistant and adds a built-in light, making it the automation-friendly pick when CO coverage is not needed. Buy the First Alert SMCO410 for combined smoke and CO safety with a long warranty; buy the Shelly Plus for a cheaper, well-rated, integration-rich smoke alarm.
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FeatureFirst Alert SMCO410 Smoke Detector & CO AlarmShelly Plus Smoke AlarmWinner
Price$57.99€39.95Shelly Plus Smoke Alarm
Rating3.54.4Shelly Plus Smoke Alarm
Warranty10 years3 yearsFirst Alert SMCO410 Smoke Detector & CO Alarm
Battery Life10 years5 yearsFirst Alert SMCO410 Smoke Detector & CO Alarm
ConnectivityZ-Wave2.4 GHz WiFi, BluetoothShelly Plus Smoke Alarm
IntegrationsSamsung SmartThings, Home AssistantGoogle Home, Samsung SmartThings, Home AssistantShelly Plus Smoke Alarm
SensorsSmoke, COSmokeFirst Alert SMCO410 Smoke Detector & CO Alarm
AlertsFire Alerts, CO Alerts, Low Battery AlertsFire Alerts, Low Battery AlertsFirst Alert SMCO410 Smoke Detector & CO Alarm
Built-in LightNOYESShelly Plus Smoke Alarm
Steam CheckYESNOFirst Alert SMCO410 Smoke Detector & CO Alarm
ScreenNONOTie
Built-in SirenYESYESTie

Price history compared

Every price change of both, in the same store, so the gap between the two lines is what one costs more than the other.

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

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Frequently Asked Questions

Which is better overall: First Alert SMCO410 Smoke Detector & CO Alarm or 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.

What is the biggest difference between the First Alert SMCO410 Smoke Detector & CO Alarm and the Shelly Plus Smoke Alarm?

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, SmartThings and Home Assistant.

Does the Shelly Plus Smoke Alarm detect carbon monoxide?

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.

Which alarm integrates with more smart-home platforms?

The Shelly Plus Smoke Alarm integrates with more platforms, working with Google Home, 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.

Who should buy the First Alert SMCO410 Smoke Detector & CO Alarm?

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.

Who should buy the Shelly Plus Smoke Alarm?

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, SmartThings and Home Assistant, and you do not need carbon monoxide detection.

Full comparison table

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  • 24 Smoke & CO Detectors
  • 44 specs compared
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