The Best Cheap Carbon Monoxide Detector

Above-average ratings, below-average prices, no fake reviews.

From a statistical perspective, these are the best carbon monoxide detectors for the money. Several were priced under $10 in the past year.

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Carbon monoxide (CO) is a deadly gas that is colorless and odorless. It steals oxygen from vital organs, causing people to faint and eventually suffocate. Hundreds of Americans die each year from unintentional carbon monoxide poisoning (often at home, during the winter months).

Why January Is the Deadliest Month

“The average daily number of CO-related deaths was greatest during the months of January (2.07 deaths) and December (1.97 deaths) and lowest during the months of July (0.67 deaths) and August (0.67 deaths),” according to an analysis published in the U.S. Morbidity and Mortality Weekly Report. This annual spike in mortality is attributed to increased use of gas-powered furnaces and alternative power sources, such as portable generators.

Landlords are required to install carbon monoxide detectors in each apartment they rent in most U.S. states; some states also require homeowners to have a CO detector. Like a smoke detector, CO detectors are often battery-operated, wall-mountable devices that beep or chirp when something is wrong. Plug-in models connect to a wall outlet and use a backup battery.

The best carbon monoxide detectors are UL-listed: This means that the unit meets or exceeds UL’s 2034 Standards for a CO detector’s sensitivity, stability, loudness and more. Because all CO detectors have expiration dates, it’s advisable to purchase a recently manufactured unit.

Some carbon monoxide detectors use WiFi to connect with a smart home system. This is a useful feature for certain caregivers, like an adult who is monitoring an elderly parent from afar.

How Much Does a Carbon Monoxide Detector Cost?

A basic carbon monoxide detector (with verified, above-average reviews) costs approximately $27, according to a 12-month analysis of price trends. Those same CO detectors cost around $10 while on sale: an average discount of 63%. Here are the best inexpensive carbon-monoxide detectors:

Methodology for Selecting Products

I use data science to discover above-average products that are selling for below-average prices. To find carbon monoxide detectors with below-average prices, I first assemble a list of candidates, then organize those products by their 12-month average sale price, determine the median value and then exclude any alarm with a price above the mid-point.

To find CO detectors with above-average reviews, I measure the relationship between 1, 2, 3, 4 and 5 star ratings and flag outliers that fall outside of a normal statistical distribution. I also discount paid, sponsored and unverified reviews as well as unhelpful review behaviors from verified customers. Models with an average adjusted rating of less than 3.9 out of 5 are excluded; in the end, fewer than 5% of the analyzed products remain.

First Alert Carbon Monoxide Detector with Digital Display, CO710

Carbon Monoxide Detector with Digital Display, CO710 — Image Credit: First Alert

Good Value: $34 | Great Deal: $23

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First Alert’s digital CO detector is compact, easy to install and it has a non-replaceable battery that reduces uncertainty and false alarms, according to several online customers. Many reviewers wish this unit displayed the current CO level by default rather than the room temperature; others wish it supported Celsius.

Kidde KN-COB-B-LP Nighthawk Carbon Monoxide Alarm

KN-COB-B-LP Nighthawk Carbon Monoxide Alarm — Image Credit: Kidde

Good Value: $23 | Great Deal: $14

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Kidde’s battery-operated CO detector has a low profile, a loud alarm and it is easy to wall mount, according to several online customers. Some reviewers say that the batteries fit snugly and are hard to change.

Kidde KN-COB-B-LP2 Carbon Monoxide Alarm

Kidde KN-COB-B-LP2 Carbon Monoxide Alarm (21028805) — Image Credit: Kidde

Good Value: $16 | Great Deal: $5

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Several online customers called their fire department after this unit alerted them, later discovering that a furnace or heater was leaking carbon monoxide. Some customers had difficulty mounting this unit to a wall.

First Alert Smoke Detector and Carbon Monoxide Detector (SCO5CN)

First Alert Smoke Detector and Carbon Monoxide Detector (SCO5CN) 1039837 — Image Credit: BRK Brands

Good Value: $36 | Great Deal: $9

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Several grateful customers say this CO detector saved their lives by alerting them to gas leaking from a dryer, water heater or other appliance. However, some reviewers say that it’s hard to hear the difference between the smoke alarm and the CO alarm; others complain that false alarms are triggered by shower steam.

Kidde KNCOB-DP2 Plug-In Carbon Monoxide Alarm with Battery Backup

Kidde KNCOB-DP2 Carbon Monoxide Alarm (21027451) — Image Credit: Kidde

Good Value: $20 | Great Deal: $11

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This CO detector is easy to install and operate, according to several online customers. Some reviewers say this unit emitted a high-pitched sound that drove their dogs crazy, so they exchanged it for a different model.

Kidde Model C3010 Worry-Free Carbon Monoxide Detector

Model C3010 Worry-Free Carbon Monoxide Detector (21027440) — Image Credit: Kidde

Good Value: $30 | Great Deal: $9

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This Kidde monitor detected deadly CO-levels caused by clogged flues or leaking furnaces, according to several thankful customers. Some reviewers say their unit’s lifespan was much shorter than 10 years.

Nighthawk AC Plug-In Carbon Monoxide Alarm with Digital Display

Carbon Monoxide Alarm with Digital Display KN-COPP-3 (21027424) — Image Credit: Kidde

Good Value: $20 | Great Deal: $5

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Several online customers say this CO detector saved their lives because it alerted them to a furnace or hot water heater that was leaking carbon monoxide. Some angry customers received an older unit that was nearing its expiration date, so be sure to check the unit’s born-on date (on any CO detector you buy).

Kidde Model KN-COSM-XTR-BA Smoke/CO Voice Alarm

Model KN-COSM-XTR-BA Smoke/CO Voice Alarm (21026042) — Image Credit: Kidde

Good Value: $39 | Great Deal: $20

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This Kidde alarm alerted several customers to a CO leak caused by a broken furnace, water heater or uncontrolled fire, saving their lives. Some reviewers were frustrated that this unit only accepts specific brands of batteries; others caution that the “voice alarm” is not as audible as a high-pitched beep or siren.

Note: This item was heavily discounted on Black Friday.

About the Author: John DeFeo is a data scientist who specializes in the analysis of online customer reviews. He has also researched and written about HEPA air purifiers and CPAP cleaning machines.