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The Best 4Aggregated review·9 sources·updated September 27, 2026·checked October 2, 2026

Best Carbon Monoxide Detectors

Top 4 carbon monoxide detectors reviewed and ranked.

This guide aggregates 9 published reviews across 4 products; the thinnest-sourced pick rests on 1. No publisher printed a score for the top pick — its rating is derived from what reviewers wrote. How we rank.

Verdict is reader-supported. As an Amazon Associate we earn from qualifying purchases. Some links on this page are affiliate links — if you click through and buy, we may earn a small commission at no extra cost to you. Our ratings are sourced from independent publications, not sponsors.
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 $130.1. Runner-up: Kidde Battery-Operated Carbon Monoxide Alarm (~$25.99).

Read the Kidde Smart Smoke + Carbon Monoxide Alarm review →$130.1 · Check Price on Amazon
At a glance4 products ▾
1Kidde Smart Smoke + Carbon Monoxide AlarmTop Score
2 sourcesall derived
$130.1Best for: buyers seeking affordable smart home integration
$130.1 · Check Price on Amazon
2Kidde Battery-Operated Carbon Monoxide Alarm
1 sourceall derived
$25.99Best for: families wanting a simple battery-powered CO alarm
$25.99 · Check Price on Amazon
3Siterwell Wireless Interconnected Smoke & CO Alarm
3 sources1 derived
$49.99Best for: renters or temporary living situations seeking affordable interconnected protection
$49.99 · Check Price on Amazon
4Siterwell Hardwired Interconnected Smoke & CO Detector
3 sources
$138.99Best for: budget-conscious homeowners seeking interconnected protection
$138.99 · 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.

The full ranking

How we rank →
Kidde Smart Smoke + Carbon Monoxide Alarm
#1 · Top Score
Best for: buyers seeking affordable smart home integration
Kidde Smart Smoke + Carbon Monoxide Alarm
2 sourcesall derived$130.1as of Oct 2
▾Why it's ranked here

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
  • — Less feature-rich compared to discontinued Nest Protect, according to Wirecutter
  • — Requires Wi-Fi connection for smart features
$130.1 · Check Price on AmazonFull review →vs. Kidde Battery-Operated Carbon Monoxide Alarm →
Kidde Battery-Operated Carbon Monoxide Alarm
#2
Best for: families wanting a simple battery-powered CO alarm
Kidde Battery-Operated Carbon Monoxide Alarm
1 sourceall derived$25.99as of Oct 2
▾Why it's ranked here

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
$25.99 · Check Price on AmazonFull review →vs. Kidde Smart Smoke + Carbon Monoxide Alarm →
Siterwell Wireless Interconnected Smoke & CO Alarm
#3
Best for: renters or temporary living situations seeking affordable interconnected protection
Siterwell Wireless Interconnected Smoke & CO Alarm
3 sources1 derived$49.99as of Oct 2
▾Why it's ranked here

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
$49.99 · Check Price on AmazonFull review →vs. Kidde Smart Smoke + Carbon Monoxide Alarm →
Siterwell Hardwired Interconnected Smoke & CO Detector
#4
★ Premium Pick
Best for: budget-conscious homeowners seeking interconnected protection
Siterwell Hardwired Interconnected Smoke & CO Detector
3 sources$138.99as of Oct 2
▾Why it's ranked here

The SITERWELL Hardwired Interconnected Smoke & CO Detector offers affordable, reliable protection with a 10-year built-in lithium battery and the ability to connect up to 18 units throughout a home. According to reviewers, it provides clear voice warnings in both English and French, and installation is straightforward with included hardware. The device features a Do Not Disturb mode to silence false alarms during cooking, and includes visual indicators for operational status and fault conditions. While it's designed for hardwired installation, it can also be used wirelessly. This makes it a solid choice for homeowners seeking interconnected protection without the complexity of full hardwired systems, though it may not suit those wanting smart home app integration.

Strengths
  • — 10-year long-life lithium battery built-in
  • — Interconnects up to 18 devices for whole-home alerts
Watch-outs
  • — Requires hardwiring for full functionality
  • — Potential mounting alignment issue
$138.99 · Check Price on AmazonFull review →vs. Kidde Smart Smoke + Carbon Monoxide Alarm →
Reviews aggregated from
ThegadgetflowSiterwellelectronicsThe New York TimesJustadadtipsConsumer ReportsTechutopia

Spec comparison

4 products
vs
SpecKidde Smart Smoke + Carbon Monoxide AlarmKidde Battery-Operated Carbon Monoxide Alarm
Detection TypeSmoke and carbon monoxideCarbon monoxide
Power SourceHardwired with battery backup3 AA batteries (included)
ConnectivityWi-Fi, Amazon Alexa, Google Home—
Alert TypeSmartphone notificationsLoud alarm with flashing light
InstallationSimple SetupWall bracket included
Dimensions1.6"D x 5.22"W x 5.22"H1.5"D x 4.5"W x 2.75"H
Battery Life—10 years
Alarm Volume—85 decibels
Sensor Type—Electrochemical
Material——

Frequently asked questions

Which carbon monoxide detector should I buy?
Kidde Smart Smoke + Carbon Monoxide Alarm holds the top score 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 September 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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