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Smoke & CO Detectors · Head to head

First Alert SMCO410 Smoke Detector & CO Alarm vs Google Nest Protect (Battery)

Full Smart Smoke & CO Detectors comparison in 2026

Updated October 2026
Data from Amazon and official First Alert and Google sites.
2026 verdict
When a smoke and carbon monoxide alarm has to do more than beep, the Google Nest Protect (Battery) is the stronger pick of these two.
Google Nest Protect (Battery)
Winner
Google Nest Protect (Battery)
$399.99
Buy on Amazon USACheck price
It is the better reviewed of the pair and the only one that speaks an early warning naming the room, senses occupancy, motion, temperature, humidity and ambient light, lights a pathlight, tests itself hundreds of times a day and interconnects wirelessly. The First Alert SMCO410 Smoke Detector & CO Alarm answers with a much lower price, a 10-year sealed battery matched by a 10-year warranty and Z-Wave connectivity that reaches Ring Alarm and Home Assistant. Both detect smoke and carbon monoxide and reduce cooking nuisance alarms. Pick the Google Nest Protect (Battery) for early spoken warnings and Google Home, and the First Alert SMCO410 Smoke Detector & CO Alarm for a long-life alarm inside a Z-Wave system.
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FeatureFirst Alert SMCO410 Smoke Detector & CO AlarmGoogle Nest Protect (Battery)Winner
Price$64.99$399.99First Alert SMCO410 Smoke Detector & CO Alarm
Rating3.54.4Google Nest Protect (Battery)
Warranty10 years2 yearsFirst Alert SMCO410 Smoke Detector & CO Alarm
Battery Life10 years2 yearsFirst Alert SMCO410 Smoke Detector & CO Alarm
ConnectivityZ-Wave2.4 GHz WiFi, Bluetooth, OtherGoogle Nest Protect (Battery)
SensorsSmoke, COSmoke, CO, Occupancy, Temperature, Humidity, Ambient Light, MotionGoogle Nest Protect (Battery)
Built-in LightNOYESGoogle Nest Protect (Battery)
Tests ItselfNOYESGoogle Nest Protect (Battery)
PathlightNOYESGoogle Nest Protect (Battery)
IntegrationsSamsung SmartThings, Home AssistantGoogle Home, Home AssistantTie
ScreenNONOTie
AlertsFire Alerts, CO Alerts, Low Battery AlertsFire Alerts, CO Alerts, Low Battery AlertsTie

What the differences mean

Warnings and sensing

The Google Nest Protect (Battery) speaks an early warning that names the room and adds occupancy, motion, temperature, humidity and ambient-light sensors. The First Alert SMCO410 Smoke Detector & CO Alarm detects smoke and CO with a built-in siren, but has no spoken voice and no extra environmental sensing.

Self-testing and light

The Google Nest Protect (Battery) runs a monthly self-test over 400 times a day and lights a pathlight when you walk under it at night. The First Alert SMCO410 Smoke Detector & CO Alarm has neither a self-test function nor a pathlight.

Battery and warranty

The First Alert SMCO410 Smoke Detector & CO Alarm carries a sealed lithium battery rated for 10 years behind a 10-year warranty. The Google Nest Protect (Battery) runs on six AA cells rated for about 2 years with a 2-year warranty, then disables itself at the end of its fixed life.

Smart home reach

The First Alert SMCO410 Smoke Detector & CO Alarm connects over Z-Wave to Ring Alarm, SmartThings and Home Assistant. The Google Nest Protect (Battery) joins Google Home and Home Assistant over Wi-Fi, with no Z-Wave.

Price

The First Alert SMCO410 Smoke Detector & CO Alarm costs noticeably less than the Google Nest Protect (Battery), which is the premium alarm of the pair.

Which one to buy if

What owners say

Google Nest Protect (Battery) owners lead with the spoken early warning that names the room before the loud alarm, and with phone alerts when they are away, several describing catching a real toaster-oven fire or a carbon monoxide leak in time. They value that it tests itself and emails a monthly report, that units interconnect, and that the automatic pathlight doubles as a night light. Their complaints run to the high price, a fixed 10-year life, batteries that must be specific lithium AAs, an abrupt low-battery warning, and the sense that it stays inside the Google Home and Home Assistant world rather than Alexa, HomeKit or Matter.

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
  • Google Nest Protect (Battery)

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Frequently Asked Questions

Which is better overall: First Alert SMCO410 Smoke Detector & CO Alarm or Google Nest Protect (Battery)?

The Google Nest Protect (Battery) is the more capable alarm, with an early spoken warning, self-testing, a pathlight and a deeper sensor set. The First Alert SMCO410 Smoke Detector & CO Alarm wins on price, a 10-year battery and warranty, and Z-Wave support for Ring and Home Assistant.

What is the biggest difference between the First Alert SMCO410 Smoke Detector & CO Alarm and the Google Nest Protect (Battery)?

The warnings. The Google Nest Protect (Battery) speaks the room name before the alarm and self-tests daily, while the First Alert SMCO410 Smoke Detector & CO Alarm sounds a siren with no voice and no self-test, but runs 10 years on a sealed battery.

Do these alarms work with Alexa or Apple Home?

No. The First Alert SMCO410 Smoke Detector & CO Alarm connects over Z-Wave to Ring Alarm, SmartThings and Home Assistant. The Google Nest Protect (Battery) works with Google Home and Home Assistant. Neither supports Alexa, Apple HomeKit or Matter.

Which alarm lasts longer, the First Alert SMCO410 Smoke Detector & CO Alarm or the Google Nest Protect (Battery)?

The First Alert SMCO410 Smoke Detector & CO Alarm, with a sealed battery and warranty both rated for 10 years. The Google Nest Protect (Battery) runs about 2 years on six AA cells and disables itself at the end of its fixed 10-year life.

Who should buy the Google Nest Protect (Battery)?

Households that want combined smoke and CO protection with spoken early warnings, phone alerts away from home, self-testing and a pathlight, especially those already in Google Home.

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

A Z-Wave or Ring Alarm household that wants smoke and CO reporting into its hub, with a 10-year sealed battery and lower upfront cost.

Full comparison table

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