Best Carbon Monoxide Detectors for Home

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Published October 19, 2026. Prices and specs checked October 17, 2026.

For most homes, the carbon monoxide detector to buy is the Kidde COBD10, a sealed 10-year battery model with a digital display, at $51.97 from Home Depot. Kidde’s plug-in 900-0280 ($61.63) suits an outlet outside the bedrooms. The AA-powered COBD ($29.97) and COB ($25.47) cost less.

I’ve spent years around wood stoves, shop heaters and generators on a farm, and all three burn fuel close to where people sleep. What I learned is that carbon monoxide gives no smell and no warning. NFPA describes it as an odorless, colorless gas created when fuels burn incompletely, so the alarm is the only thing that speaks up. Where it goes and when it gets replaced matter as much as the model on the box.

How These Four Carbon Monoxide Detectors Compare

All four are Kidde models. First Alert’s own store marks its CO400, CO615 and CO710 alarms discontinued and its newer CO3 and CO5 models sold out, so the real choice here is power source and display. The table lines up what Home Depot’s listings and Kidde’s own pages state for each one.

Detector	Power	Display	Listing wording	Warranty	Price
Kidde COBD10	Built-in 10-year battery	Digital, backlit	Tested to meet UL 2034 5th Edition and ETL Listed	10-year limited	$51.97
Kidde 900-0280	Plug-in, 120 V, sealed 10-year backup battery	Digital, shows current and peak CO	UL Listed	10-year limited	$61.63
Kidde COBD	Two AA batteries	Digital, backlit	Tested to meet UL 2034 5th Edition and ETL Listed	10-year limited	$29.97
Kidde COB	Two AA batteries	LED status indicators only	No UL wording on the listing	10-year warranty (Kidde)	$25.47

Prices are Home Depot’s listings on October 17, 2026, and Kidde and Home Depot put the alarm at 85 dB on the COBD10, COBD and COB. Follow the manufacturer’s instructions, and look for a UL or ETL listing on any alarm you buy.

Kidde COBD10: Best 10-Year Alarm With a Display

The COBD10 runs on a built-in battery Kidde rates at 10 years, so there is nothing to change. Home Depot lists it at $51.97 with a digital backlit display, LED status lights for power, alarm and unit health, and an 85 dB alarm. Kidde backs it with a 10-year limited warranty.

The sealed battery is the whole appeal. CPSC says to replace alarm batteries at least once a year unless the alarm has a sealed 10-year battery, and this one removes that chore. Home Depot’s listing says it can save up to $40 over the life of the alarm in battery replacements. Skip it if you want a battery you can swap. Kidde’s page also warns that constant high or low temperatures or high humidity may shorten battery life, so read the manual before hanging it in an unheated space.

Kidde 900-0280: Best Plug-In With Battery Backup

The 900-0280 plugs into a 120-volt outlet and carries a sealed 10-year lithium battery as backup. Home Depot lists it at $61.63 as the Kidde 10-Year Worry-Free Plug-In with Digital Display, UL Listed, with a hush button and a tamper-resistant design. The display shows the current CO level and the peak level reached since the peak button was last pressed.

Home Depot’s Q&A says the sealed battery covers a power outage but cannot run the alarm on its own for 10 years. That fits CPSC’s advice that plug-in and hard-wired alarms should have battery backup. It suits a hallway outlet outside the bedrooms, where nobody wants to climb a ladder. Skip it if the outlets near the sleeping areas sit behind a bed or a dresser. CPSC says to avoid spots that furniture or draperies can cover.

Kidde COBD: Best AA-Powered Alarm With a Display

The COBD takes two included AA batteries and shows real-time CO levels on a backlit digital display. Home Depot lists it at $29.97, says it is tested to meet UL 2034 5th Edition and ETL Listed, and notes the 85 dB alarm and the 10-year limited warranty. Kidde’s product page says the batteries need changing about once a year under normal conditions.

This is the sensible middle. The COBD10 costs $22.00 more ($51.97 minus $29.97) and what that money buys is no yearly battery swap. Skip the COBD if you know a yearly battery change will slip your mind. A sealed battery takes that chance away.

Kidde COB: Lowest-Priced Pick Here

The COB is Kidde’s plain AA-powered alarm, listed at $25.47 at Home Depot with LED status indicators and no digital display. Kidde’s page describes a loud 85 dB alarm with a flashing light and the same yearly AA battery routine as the COBD. It will not tell you a number, only whether it is alarming.

Home Depot’s listing says the COB is upgraded to meet the most current safety standards for CO alarms, but it does not print UL 2034 wording the way the COBD listing does. Check the box for the listing mark before you pay. Skip the COB if you want a CO reading on a display rather than a light and a siren.

Carbon Monoxide Detector Battery vs Plug-In

Battery alarms go anywhere on the wall and keep working in an outage. Plug-ins never need a battery for normal power but depend on an outlet in the right spot. CPSC says hard-wired and plug-in CO alarms should have battery backup, and that is why the 900-0280 carries a sealed one.

A sealed 10-year battery trades flexibility for peace of mind. You cannot swap it, and the whole alarm gets replaced when the battery or the sensor is done. AA models cost less up front and ask for one battery change a year. Whichever you pick, CPSC says to test alarms monthly, and that the test button checks the circuitry rather than the accuracy of the sensor.

Where to Place Carbon Monoxide Detectors

CPSC says to install CO alarms on each level of the home and outside sleeping areas. The Minnesota State Fire Marshal puts a number on it: within 10 feet of each sleeping room or inside each one. In a two-story house with every bedroom upstairs, that works out to at least one in the upstairs hall and one on the main level.

Keep alarms away from heating vents and anywhere furniture or draperies could cover them. CPSC does not recommend putting them in kitchens or above fuel-burning appliances. Height is flexible. Kidde’s FAQ says carbon monoxide disperses evenly in the air, so a detector can go anywhere on the wall. A furnace room or a finished basement is a case for the manual and your local fire code.

Generators and Heaters: Where Carbon Monoxide Comes From

CPSC says more than 200 people in the United States die every year from accidental CO poisoning tied to consumer products. More than 100 of those deaths are linked to portable generators. CPSC’s rule for generators is blunt: never run a portable generator or any gasoline-powered tool in or near an enclosed space, because even with doors and windows open it can build to lethal levels.

Outage season is when a detector gets tested for real. If you are lining up storm power, our portable power station guide covers units that burn no fuel at all. If a space heater is on your list for a small room, check its manual for where it can and cannot go. Sealing drafts is part of the same fall routine, and our draft stopper guide shows how to winterize your doors and windows.

How Often to Replace Carbon Monoxide Detectors

CPSC says alarms have a recommended replacement age, found in the product literature or from the maker. The numbers vary by source. Kidde’s product pages say 7 to 10 years in one place and 5 to 10 years in their FAQ, while the Minnesota State Fire Marshal says every five to seven years.

Treat the manual for your model as the date that counts, and treat any end-of-life chirp as a replace-now signal. Kidde’s pages give a range, not a date for each model. The practical move is to write the install date on the back of the alarm. Replace batteries on AA models once a year, per CPSC, and test every alarm monthly.

Carbon Monoxide Detector Recalls to Check Before You Buy

The CPSC recall database lists past Kidde recalls on CO and combination alarms. Kidde recalled Nighthawk and Lifesaver CO alarms on March 24, 1999. It recalled smoke and combination smoke/CO alarms including the KN-COSM-IBA on September 11, 2014. It recalled the KN-COSM-IB combination alarm on November 10, 2016, and TruSense models including the 2070-VDSCR and 2070-VASCR on May 6, 2021.

None of the four detectors here, the COBD10, 900-0280, COBD and COB, appear in those CPSC notices, and the recalled models are different part numbers. CPSC also lists recent CO and combination alarm recalls from other brands, including Treatlife on June 25, 2026 and Apollo America on June 5, 2025. Search CPSC’s recall list for the exact model number before you buy any alarm.

Frequently Asked Questions About Carbon Monoxide Detectors

Do carbon monoxide detectors expire?

Yes. CPSC says alarms have a recommended replacement age, which you find in the product literature or from the manufacturer. The Minnesota State Fire Marshal puts that at five to seven years.

Can you put a carbon monoxide detector in the kitchen?

CPSC does not recommend installing CO alarms in kitchens or above fuel-burning appliances. Put them on each level and outside sleeping areas instead, away from heating vents and anything that could cover them.

Does the test button check the carbon monoxide sensor?

No. CPSC says the test button checks whether the circuitry is working, not the accuracy of the sensor. Press it monthly anyway, and replace the alarm on the schedule in its manual.

Do plug-in alarms need a battery backup?

Yes. CPSC says hard-wired or plug-in CO alarms should have battery backup, so a power outage does not leave the house unprotected. The Kidde 900-0280 includes a sealed 10-year backup battery for this reason.

Which Carbon Monoxide Detector Should You Buy?

For most homes, I would start with the Kidde COBD10. The sealed battery removes the yearly battery change, and the display shows a reading. If the outlets by your bedrooms are clear, the 900-0280 does the same job with a plug. The $29.97 COBD is the better buy for a tighter budget and a reliable habit of changing batteries once a year. The $25.47 COB is the price floor, once you confirm the UL mark on the box.

Whatever you buy, put one on each level and outside the sleeping areas, test it monthly, and replace it on the date in the manual. In an emergency, call 911.

Prices are approximate, current as of publication, and change frequently — confirm the latest price with the retailer before buying.

This article is for general information only and is not medical advice. Talk to a licensed clinician about your own situation.