The Best 5Aggregated review·12 sources·updated October 10, 2026·checked October 6, 2026

Best Carbon Monoxide Detectors

Top 5 carbon monoxide detectors reviewed and ranked.

This guide aggregates 12 published reviews across 5 products; the thinnest-sourced pick rests on 2. No publisher printed a score for the top pick — its rating is derived from what reviewers wrote. How we rank.

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Quick answer

Kidde Smart Smoke + Carbon Monoxide Alarm is our top pick for carbon monoxide detectors — an averaged 4.5/5 across 2 published reviews at about $75. Runner-up: X-Sense SC07-WX Smart Smoke and CO Alarm (~$36.54).

Read the Kidde Smart Smoke + Carbon Monoxide Alarm review →$75 · Check Price on Amazon

At a glance

Tap any product for the full review

#	Product	Rating	Price	Best for
1	Kidde Smart Smoke + Carbon Monoxide AlarmTop Pick	4.5 2 sourcesall derived	$75	buyers seeking affordable smart home integration	$75 · Check Price on Amazon
2	X-Sense SC07-WX Smart Smoke and CO Alarm	4.2 1 source	$36.54	Renters and homeowners who want phone alerts for smoke and CO without hardwiring	$36.54 · Buy at x-sense.com
3	First Alert SC5 Battery Smart Smoke & Carbon Monoxide Alarm	4.2 1 source	$125	google home households who want smoke and co alerts on their phone without wiring	$125 · Check Price on Amazon
4	Kidde Battery-Operated Carbon Monoxide Alarm	4.0 2 sourcesall derived	$25.99	families wanting a simple battery-powered CO alarm	$25.99 · Check Price on Amazon
5	Siterwell Wireless Interconnected Smoke & CO Alarm	Unrated3 sources	$41.99	renters or temporary living situations seeking affordable interconnected protection	$41.99 · Check Price on Amazon

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.

At a glance5 products ▾

1Kidde Smart Smoke + Carbon Monoxide AlarmTop Pick

4.5

2 sourcesall derived

$75Best for: buyers seeking affordable smart home integration

$75 · Check Price on Amazon

2X-Sense SC07-WX Smart Smoke and CO Alarm

4.2

1 source

$36.54Best for: Renters and homeowners who want phone alerts for smoke and CO without hardwiring

$36.54 · Buy at x-sense.com

3First Alert SC5 Battery Smart Smoke & Carbon Monoxide Alarm

4.2

1 source

$125Best for: google home households who want smoke and co alerts on their phone without wiring

$125 · Check Price on Amazon

4Kidde Battery-Operated Carbon Monoxide Alarm

4.0

2 sourcesall derived

$25.99Best for: families wanting a simple battery-powered CO alarm

$25.99 · Check Price on Amazon

5Siterwell Wireless Interconnected Smoke & CO Alarm

Unrated3 sources

$41.99Best for: renters or temporary living situations seeking affordable interconnected protection

$41.99 · Check Price on Amazon

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.

Reviews aggregated from

CNETBobvilaThe New York TimesPCMagThe SpruceJustadadtipsThegadgetflow

The full ranking

How we rank →

Kidde Smart Smoke + Carbon Monoxide Alarm

#1 · Top Pick

Best for: buyers seeking affordable smart home integration

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

Watch-outs

— Requires Wi-Fi connection for smart features

▾Why it's ranked here

Strengths

— Sends speedy notifications to smartphone when triggered, per Wirecutter
— Can interconnect with non-smart Kidde hardwired alarms, per Wirecutter

Watch-outs

— Requires Wi-Fi connection for smart features

$75 · Check Price on Amazon Full review →vs. X-Sense SC07-WX Smart Smoke and CO Alarm →

Best for: Renters and homeowners who want phone alerts for smoke and CO without hardwiring

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

Watch-outs

— Does not work with Alexa, Apple HomeKit or Google Home
— No voice alerts

▾Why it's ranked here

Strengths

— Reasonably priced for a Wi-Fi alarm, per PCMag
— LCD shows the CO level in ppm and the battery level

Watch-outs

— Does not work with Alexa, Apple HomeKit or Google Home
— No voice alerts

$36.54 · Buy at x-sense.com Full review →vs. Kidde Smart Smoke + Carbon Monoxide Alarm →

First Alert SC5 Battery Smart Smoke & Carbon Monoxide Alarm

★ Premium Pick

Best for: google home households who want smoke and co alerts on their phone without wiring

First Alert SC5 Battery Smart Smoke & Carbon Monoxide Alarm

4.2

1 source$125as of Oct 17

The First Alert SC5 is a battery-powered combination smoke and carbon monoxide alarm, measuring 5.75 x 5.75 x 1.6 inches, with an electrochemical CO sensor, a photoelectric smoke sensor and Google Home connectivity. CNET named it the best overall carbon monoxide detector in its lab-tested roundup, citing accurate sensors, phone alerts through Google Home and voice alerts that state what the alarm is sensing. Bob Vila rated it 4.5/5, reporting a three-minute setup with preinstalled batteries and a large centre button that silences cooking false alarms. It suits Google Home households that want smoke and CO coverage in places without wiring; homes where codes require hardwired alarms, or buyers fitting many rooms on a tight budget, should look elsewhere.

Strengths

— Detects smoke and carbon monoxide in one unit, with voice alerts that say which hazard it senses
— Links to the Google Home app via Nest Protect integration for phone alerts away from home

Watch-outs

— Battery-only power may not satisfy building codes that require a wired alarm
— Costs far more than standard alarms, which adds up when equipping a whole house

▾Why it's ranked here

Strengths

— Detects smoke and carbon monoxide in one unit, with voice alerts that say which hazard it senses
— Links to the Google Home app via Nest Protect integration for phone alerts away from home

Watch-outs

— Battery-only power may not satisfy building codes that require a wired alarm
— Costs far more than standard alarms, which adds up when equipping a whole house

$125 · Check Price on Amazon Full review →vs. Kidde Smart Smoke + Carbon Monoxide Alarm →

Best for: families wanting a simple battery-powered CO alarm

Kidde Battery-Operated Carbon Monoxide Alarm

4.0

2 sourcesall derived$25.99as of Oct 2

The Kidde Battery-Operated Carbon Monoxide Alarm offers a 10-year service life with end-of-life beeping. The unit includes a low battery alarm and green operate light. Reviewers noted it's simple to use and reliable for family safety. This alarm is ideal for households seeking a simple battery-powered CO detector.

Strengths

— Battery-operated with 10-year service life and end-of-life beep indicator
— LED status lights plus a Test/Reset button that also silences the alarm

Watch-outs

— Potential for nuisance or false alarms

▾Why it's ranked here

Strengths

— Battery-operated with 10-year service life and end-of-life beep indicator
— LED status lights plus a Test/Reset button that also silences the alarm

Watch-outs

— Potential for nuisance or false alarms

$25.99 · Check Price on Amazon Full review →vs. Kidde Smart Smoke + Carbon Monoxide Alarm →

Best for: renters or temporary living situations seeking affordable interconnected protection

Siterwell Wireless Interconnected Smoke & CO Alarm

Unrated3 sources$41.99as of Oct 11

Siterwell's wireless interconnected smoke and CO alarm offers reliable 10-year battery life and wireless interconnected functionality for up to 18 devices. The Do Not Disturb mode provides relief from nighttime false alarms, while its compact design makes it suitable for various locations including Airbnbs and RVs. Consumer Reports noted its ease of installation and accurate electrochemical sensor. This makes it ideal for renters or those seeking affordable interconnected protection without hardwiring.

Strengths

— 10-year long-life lithium battery built-in
— Wireless interconnected capability connecting up to 18 devices

Watch-outs

— potential mounting orientation issue

▾Why it's ranked here

Strengths

— 10-year long-life lithium battery built-in
— Wireless interconnected capability connecting up to 18 devices

Watch-outs

— potential mounting orientation issue

$41.99 · Check Price on Amazon Full review →vs. Kidde Smart Smoke + Carbon Monoxide Alarm →

Reviews aggregated from

CNETBobvilaThe New York TimesPCMagThe SpruceJustadadtipsThegadgetflow

Spec comparison

5 products

Spec	Kidde Smart Smoke + Carbon Monoxide Alarm	X-Sense SC07-WX Smart Smoke and CO Alarm	First Alert SC5 Battery Smart Smoke & Carbon Monoxide Alarm	Kidde Battery-Operated Carbon Monoxide Alarm	Siterwell Wireless Interconnected Smoke & CO Alarm
Detection Type	Smoke and carbon monoxide	Smoke and carbon monoxide	—	Carbon monoxide	Smoke and carbon monoxide
Power Source	Hardwired with battery backup	One CR123A battery (included)	Battery	3 AA batteries (included)	Built-in 10-year lithium battery
Connectivity	Wi-Fi, Amazon Alexa, Google Home	Wi-Fi (2.4GHz), Bluetooth	—	—	Wireless interconnected
Alert Type	Smartphone notifications	—	—	Loud alarm with flashing light	Loud alarm with flashing light
Installation	Simple Setup	—	—	Wall bracket included	Easy Install
Dimensions	1.6"D x 5.22"W x 5.22"H	5.7 x 5.7 x 2.0 in	5.75 x 5.75 x 1.6 in	1.5"D x 4.5"W x 2.75"H	3.3"D x 4.8"W x 1.7"H
Sensor Type	—	Photoelectric smoke, electrochemical CO	—	Electrochemical	Photoelectric smoke + electrochemical CO
Alarm Volume	—	85 dB	—	85 decibels	85 dB
Battery Life	—	—	—	10 years	10-year lithium

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
Battery Life	—	—

Frequently asked questions

Which carbon monoxide detector should I buy?

Kidde Smart Smoke + Carbon Monoxide Alarm is the top pick for carbon monoxide detectors — 4.5/5 averaged from 2 published reviews. 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.

When was this guide last updated?

This guide was last re-checked in October 2026. Prices, links, and source ratings are re-verified on a rolling basis, and the ranking updates when the underlying scores change.

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