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Head-to-head · Best Smart Smoke Detectors

First Alert SC5 Hardwire Smart Smoke and CO Alarm vs X-Sense SC07 Smoke & CO Alarm

Which is the better buy? Side-by-side on rating, price, strengths, and watch-outs — with the published ratings we averaged to get there.

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The short answer

X-Sense SC07 Smoke & CO Alarm comes out ahead by a narrow margin (4.2 vs 4.0). X-Sense SC07 Smoke & CO Alarm is best for: Homeowners with a 2.4GHz Wi-Fi network who want battery-powered smoke and CO alarms with phone alerts and no wiring. Read the strengths below before deciding.

First Alert SC5 Hardwire Smart Smoke and CO Alarm
Ranked #3 in Best Smart Smoke Detectors
First Alert SC5 Hardwire Smart Smoke and CO Alarm
1 sourceall derived$128.89as of Oct 6

The First Alert SC5 is engineered as a direct drop-in replacement for the discontinued Google Nest Protect, utilizing an included wiring adapter to fit existing ceiling mounts without requiring new electrical work. smarthomecompared found that its dual photoelectric and electrochemical sensors effectively distinguish between hazards like grease fires and carbon monoxide, while PureReviews noted that loud voice alerts specify both the danger type and device location for clear identification during emergencies. However, the unit lacks motion-activated pathway lighting and automated self-testing, forcing users to manually verify operation via a button press rather than relying on daily diagnostics. Because it works exclusively with the Google Home app and offers no Alexa or Apple HomeKit support, this alarm fits only households already invested in that ecosystem who prioritize easy installation over smart home versatility.

Strengths
  • — Designed as a drop-in replacement for discontinued Google Nest Protect, fitting existing ceiling mounts with included wiring adapter
  • — Features loud built-in siren with voice alerts that specify the danger type and device location
  • — Combines photoelectric smoke sensor and electrochemical CO sensor in one unit to reduce nuisance alarms
Watch-outs
  • — Lacks motion-activated pathway night light found on the Nest Protect it replaces
  • — Works exclusively with Google Home app, offering no Alexa, Apple HomeKit, or Matter support
  • — Missing self-testing automation feature, requiring manual button presses to verify operation
$128.89 · Check Price on AmazonFull review →
X-Sense SC07 Smoke & CO Alarm
Higher ratedRanked #1 in Best Smart Smoke Detectors
X-Sense SC07 Smoke & CO Alarm
1 source$35.98as of Oct 6

The Gadgeteer found that this Wi-Fi-connected detector offers valuable remote monitoring via smartphone push notifications and an LCD screen displaying carbon monoxide levels in parts per million. It supports interconnecting up to 24 units under a single account, though it is incompatible with 5GHz networks and requires users to verify their router settings for successful pairing. The device produces a deafening alarm of at least 85 decibels, but its replaceable battery means it does not satisfy rules such as New York's, which require ten-year sealed batteries or hardwiring, and Reviewed found the SC07-MR variant carried no UL label. This model fits homeowners with standard dual-band routers who prioritize app integration over hard-wired reliability, while those in jurisdictions requiring ten-year sealed batteries should look elsewhere.

Strengths
  • — Provides real-time smartphone push notifications via Wi-Fi connectivity when not at home
  • — Features an LCD screen that displays carbon monoxide levels in parts per million (ppm)
  • — Supports interconnectivity of up to 24 detectors within a single account for comprehensive coverage
Watch-outs
  • — Incompatible with 5GHz Wi-Fi networks, requiring connection to a 2.4GHz router
  • — Some variants lack UL certification and require an additional base station for smart features
$35.98 · Check Price on AmazonFull review →

Derived means the reviewer published no score, so one was inferred from their written verdict. Everything else is a number the publisher printed. How we rank.

How they stack up

First Alert SC5 Hardwire Smart Smoke and CO Alarm

The SC5 is hardwired with a lithium backup, like the Kidde Ring-Enabled detector, which uses AA backup batteries; the X-Sense SC07 runs on a CR123A lithium battery instead. The SC5 is controlled through the Google Home app, where the Kidde reports through the Ring app.

X-Sense SC07 Smoke & CO Alarm

The X-Sense SC07 Smoke & CO Alarm runs on a replaceable CR123A lithium battery, where the Kidde Ring-Enabled Smart Smoke and Carbon Monoxide Detector and the First Alert SC5 Hardwire Smart Smoke and CO Alarm are hardwired. It detects both smoke and carbon monoxide, unlike the smoke-only X-Sense XS01-M Interconnected Smart Smoke Alarm (FS31 kit), and its LCD shows CO levels in parts per million. It costs less than the Kidde and the First Alert.

Specs side-by-side

SpecFirst Alert SC5 Hardwire Smart Smoke and CO AlarmX-Sense SC07 Smoke & CO Alarm
Power SourceHardwired with Lithium backupCR123A Lithium Battery
Compatible EcosystemsGoogle Home app only—
Lifespan10 years10 Years
Sensor TypePhotoelectric smoke, Electrochemical COPhotoelectric smoke, Electrochemical CO
Dimensions5.75"D x 1.6"W x 5.75"H5.7"D x 5.7"W x 2"H
Detection TypeSmoke and Carbon MonoxidePhotoelectric Smoke / Electromechanical CO
ConnectivityFirst Alert App / Google Home—
Alarm Volume85dB at 10 feet≥85dB at 3 meters
Material—Heat-Resistant PC Plastic Material
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