Data from the official First Alert and Google sites.
2026 verdict
Battery freedom or hardwired peace of mind?
The Google Nest Protect (Wired) wins this matchup on features and owner sentiment. It adds occupancy, temperature, humidity, ambient-light and motion sensing, a pathlight and a monthly self-test that the First Alert SC5 Battery Smart Smoke & CO Alarm lacks, and it runs on mains power with a battery backup. Both detect smoke and carbon monoxide, interconnect, voice an early warning, live in Google Home and support neither Alexa, Apple HomeKit nor Matter. The First Alert SC5 Battery Smart Smoke & CO Alarm answers with a lower price, a longer 10-year warranty against 2 years, and the freedom to install anywhere without wiring. Pick the Google Nest Protect (Wired) if you have existing wiring and want the smart extras, and the First Alert SC5 Battery Smart Smoke & CO Alarm for a no-wiring install at a lower cost.
Works with
Connectivity
- Wi-Fi 2.4 GHz
vs
Winner
Price unavailable right now
Works with
Connectivity
- Wi-Fi 2.4 GHz
- Bluetooth
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| Feature | First Alert SC5 Battery Smart Smoke & CO Alarm | Google Nest Protect (Wired) | Winner |
|---|---|---|---|
| Rating | 3.6 | 4.6 | Google Nest Protect (Wired) |
| Warranty | 10 years | 2 years | First Alert SC5 Battery Smart Smoke & CO Alarm |
| Connectivity | 2.4 GHz WiFi | 2.4 GHz WiFi, Bluetooth, Other | Google Nest Protect (Wired) |
| Sensors | Smoke, CO | Smoke, CO, Occupancy, Temperature, Humidity, Ambient Light, Motion | Google Nest Protect (Wired) |
| Built-in Light | NO | YES | Google Nest Protect (Wired) |
| Tests Itself | NO | YES | Google Nest Protect (Wired) |
| Pathlight | NO | YES | Google Nest Protect (Wired) |
| Integrations | Google Home | Google Home, Home Assistant | Tie |
| Screen | NO | NO | Tie |
| Alerts | Fire Alerts, CO Alerts, Low Battery Alerts | Fire Alerts, CO Alerts, Low Battery Alerts | Tie |
| Built-in Siren | YES | YES | Tie |
| Steam Check | YES | YES | Tie |
What the differences mean
Power
The First Alert SC5 Battery Smart Smoke & CO Alarm is battery-only, on six CR123A cells. The Google Nest Protect (Wired) runs on mains power with a 3 AA backup, so it never needs a routine battery change.
Placement
The First Alert SC5 Battery Smart Smoke & CO Alarm installs anywhere with no wiring, which suits rentals. The Google Nest Protect (Wired) needs an existing alarm circuit.
Sensors
The Google Nest Protect (Wired) adds occupancy, temperature, humidity, ambient-light and motion sensing. The First Alert SC5 Battery Smart Smoke & CO Alarm senses smoke and carbon monoxide only.
Pathlight and self-test
Only the Google Nest Protect (Wired) has a night pathlight and a self-test that emails a monthly report. The First Alert SC5 Battery Smart Smoke & CO Alarm has neither.
Warranty
Ten years on the First Alert SC5 Battery Smart Smoke & CO Alarm against two on the Google Nest Protect (Wired).
Price and availability
The First Alert SC5 Battery Smart Smoke & CO Alarm is the lower priced and still in production. The discontinued Google Nest Protect (Wired) is limited to remaining retail stock.
Which one to buy if
- you have no alarm wiring
The First Alert SC5 Battery Smart Smoke & CO Alarm installs anywhere on batteries.
- you have existing alarm wiring and want no battery changes
The Google Nest Protect (Wired) runs on mains power with a backup.
- you want a night pathlight
Only the Google Nest Protect (Wired) lights your way and senses when the room is dark.
- you want the lowest price and longest warranty
The First Alert SC5 Battery Smart Smoke & CO Alarm costs less and carries 10 years of cover.
- you want self-testing with a monthly report
The Google Nest Protect (Wired) checks itself continuously and reports monthly.
- + Warranty: 10 years
- - Rating: 3.6 vs 4.6
- - Connectivity: 2.4 GHz WiFi vs 2.4 GHz WiFi, Bluetooth, Other
Winner
Price unavailable right now
- + Rating: 4.6
- + Connectivity: 2.4 GHz WiFi, Bluetooth, Other
- + Sensors: Smoke, CO, Occupancy, Temperature, Humidity, Ambient Light, Motion
- - Warranty: 2 years vs 10 years
What owners say
Owners of both alarms agree that a spoken early warning naming the room and phone alerts when away are worth having, and both groups value hardwiring or long battery life ending the routine battery change. Google Nest Protect (Wired) owners single out the self-testing monthly report, the pathlight and the wireless interconnection that works even with Wi-Fi off, while some tire of it only linking to other Nest Protects and note the high price. First Alert SC5 Battery Smart Smoke & CO Alarm owners single out how easily it replaces a Nest Protect and the loud voice-guided siren, but miss the pathlight and describe a recurring share of nuisance false alarms.
Frequently Asked Questions
Which is better overall: First Alert SC5 Battery Smart Smoke & CO Alarm or Google Nest Protect (Wired)?
The Google Nest Protect (Wired) on features and owner sentiment, with extra sensors, a pathlight and self-testing. The First Alert SC5 Battery Smart Smoke & CO Alarm wins on price, warranty and the freedom to install it without wiring.
What is the biggest difference between the First Alert SC5 Battery Smart Smoke & CO Alarm and the Google Nest Protect (Wired)?
Power and sensing. The First Alert SC5 Battery Smart Smoke & CO Alarm is battery-only, while the Google Nest Protect (Wired) is hardwired and adds occupancy, temperature, humidity, light and motion sensors plus a pathlight.
Do the First Alert SC5 Battery Smart Smoke & CO Alarm and the Google Nest Protect (Wired) work with Alexa or Apple HomeKit?
No, neither does. Both connect through Google Home and neither supports Alexa, Apple HomeKit, SmartThings or Matter. The Google Nest Protect (Wired) also works in Home Assistant through a community integration.
Which one has a longer warranty?
The First Alert SC5 Battery Smart Smoke & CO Alarm, at 10 years against 2 years on the Google Nest Protect (Wired).
Are the First Alert SC5 and Google Nest Protect (Wired) both Wi-Fi alarms?
Yes. Both connect over 2.4 GHz Wi-Fi and are set up through their apps, the First Alert app for the First Alert SC5 Battery Smart Smoke & CO Alarm and the Nest app for the Google Nest Protect (Wired).
Who should buy the First Alert SC5 Battery Smart Smoke & CO Alarm?
Buyers with no alarm wiring, renters, or anyone wanting a lower-cost battery alarm with a 10-year warranty and Google Home alerts, who can do without the pathlight and extra sensors.
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