Head-to-head · Best Carbon Monoxide Detectors

Kidde Smart Smoke + Carbon Monoxide Alarm vs X-Sense SC07-WX Smart Smoke and 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

Kidde Smart Smoke + Carbon Monoxide Alarm comes out ahead by a clear margin (4.5 vs 4.2). Kidde Smart Smoke + Carbon Monoxide Alarm is best for: buyers seeking affordable smart home integration. Read the strengths below before deciding.

Higher ratedRanked #1 in Best Carbon Monoxide Detectors

Kidde Smart Smoke + Carbon Monoxide Alarm

4.5

2 sourcesall derived$75as of Oct 17

The Kidde Smart Smoke + Carbon Monoxide Alarm is a strong pick for 2026, praised for its reliable fire and CO detection, easy installation, and ability to send instant smartphone alerts. Reviewers noted it effectively reduces false alarms that might lead to battery removal, and it can interconnect with older Kidde models. While it lacks some advanced features of the discontinued Nest Protect, it offers a cost-effective smart home safety solution. It's ideal for those seeking a balance of functionality and affordability, though users with existing Nest systems may find better integration elsewhere.

Strengths

— Sends speedy notifications to smartphone when triggered, per Wirecutter
— Can interconnect with non-smart Kidde hardwired alarms, per Wirecutter
— Easy to install with included wiring harness and battery backup

Watch-outs

— Requires Wi-Fi connection for smart features

$75 · Check Price on Amazon Full review →

Ranked #2 in Best Carbon Monoxide Detectors

X-Sense SC07-WX Smart Smoke and CO Alarm

4.2

1 source$36.54as of Oct 10

The X-Sense SC07-WX is a battery-powered combination smoke and carbon monoxide alarm with built-in Wi-Fi and a 1.2-inch LCD that shows the CO level in parts per million. PCMag rated it 4.0 out of 5, calling it reasonably priced and easy to install, with push and email alerts and optional professional monitoring with fire dispatch. PCMag's criticisms are that it does not work with Alexa, Apple HomeKit or Google Home, has no voice alerts, and cannot be interconnected with other alarms.

Strengths

— Reasonably priced for a Wi-Fi alarm, per PCMag
— LCD shows the CO level in ppm and the battery level
— Push and email alerts, with an in-app button to silence the alarm

Watch-outs

— Does not work with Alexa, Apple HomeKit or Google Home
— No voice alerts
— Standalone: cannot be interconnected with other alarms

$36.54 · Buy at x-sense.com Full 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

Kidde Smart Smoke + Carbon Monoxide Alarm

The Kidde Smart Smoke + Carbon Monoxide Alarm is hardwired with battery backup and sends smartphone notifications, where the Siterwell Wireless Interconnected Smoke & CO Alarm runs on a built-in 10-year lithium battery. It lists Amazon Alexa and Google Home connectivity, which the X-Sense SC07-WX Smart Smoke and CO Alarm does not work with. It costs more than both, and its smart features require a Wi-Fi connection.

X-Sense SC07-WX Smart Smoke and CO Alarm

Unlike the Kidde Smart Smoke + Carbon Monoxide Alarm, which is hardwired with battery backup and lists Amazon Alexa and Google Home connectivity, the SC07-WX runs on a single replaceable battery and, per PCMag, works with no smart home platform. It is a standalone unit, whereas the Siterwell Wireless Interconnected Smoke & CO Alarm links to other alarms. Its $36.54 price is well under the Kidde Smart alarm's $130.10.

Specs side-by-side

Spec	Kidde Smart Smoke + Carbon Monoxide Alarm	X-Sense SC07-WX Smart Smoke and CO Alarm
Detection Type	Smoke and carbon monoxide	Smoke and carbon monoxide
Power Source	Hardwired with battery backup	One CR123A battery (included)
Connectivity	Wi-Fi, Amazon Alexa, Google Home	Wi-Fi (2.4GHz), Bluetooth
Alert Type	Smartphone notifications	—
Installation	Simple Setup	—
Dimensions	1.6"D x 5.22"W x 5.22"H	5.7 x 5.7 x 2.0 in
Sensor Type	—	Photoelectric smoke, electrochemical CO
Alarm Volume	—	85 dB
Display	—	1.2-inch LCD (CO ppm, battery level)
Rated Life	—	10 years

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