What is the best carbon monoxide detector?

If you want one excellent standalone carbon-monoxide detector, my pick is the Kidde 10-Year Battery CO Detector with Digital Display (C3010D).

• Kidde C3010D Carbon Monoxide Detector with Digital Display - $44.94 (Walmart)

Why I’d choose it

• 10-year sealed lithium battery — essentially no battery maintenance.
• Digital CO readout, so you can see the detected concentration rather than just hearing an alarm.
• Electrochemical sensor, the technology used by leading residential CO alarms.
• 85 dB alarm.
• Consumer Reports currently rates the C3010-D among its tested CO-detector picks.
• Current price is around $45–$50, depending on retailer.

Other good choices

• Kidde Plug-In CO Detector with Digital Display - $43.97 (The Home Depot)

• Kidde Smart Plug-In CO Detector - $56.97 (The Home Depot)

• First Alert CO615 - $35.88 (Walmart)

• Kidde Low-Level CO Detector - $40.47 (The Home Depot)

• Best plug-in: Kidde COPD — digital display plus AA battery backup.

• Best smart: Kidde COPDW — sends real-time phone alerts without requiring a subscription.

• Best budget: First Alert CO615 — plug-in, battery backup, and digital display; Consumer Reports gives it its highest score among the standalone CO detectors it tested.

• Best for lower-level CO awareness: Kidde COBDL — specifically designed to alert to smaller amounts of CO.

One important point: Don't buy just one for the whole house. CO alarms should generally be installed outside sleeping areas and on every level of the home. And a CO detector does not replace smoke alarms.

If you tell me whether you want battery, plug-in, hardwired, or smart/phone alerts, I can narrow it down to the best specific model for your house.

The "best" carbon monoxide (CO) detector depends on whether you want a simple plug-in, a smart home-integrated unit, or a combination smoke and CO alarm. Industry tests and safety experts highlight several top models for 2026:

Recommended by SafeWise , this combination smoke and CO detector features optional voice alerts to clearly communicate the specific threat and minimize panic.

A long-time favorite noted for its clear digital readout screen that displays CO levels in ppm (parts per million) and an easy plug-in design with a backup battery.

A straightforward, no-fuss plug-in detector that gives you reliable protection straight out of the box without breaking the bank.

If you are invested in a smart ecosystem, this combination smoke and CO alarm sends push notifications directly to your phone, tests itself automatically, and features a friendly human voice instead of a blaring horn. You can check details on Amazon.

Kidde Smart Smoke + Carbon Monoxide Alarm Go to product viewer dialog for this item. (Best Smart Hardwired/Battery): Favored by The New York Times - Wirecutter for seamlessly integrating smart alerts with traditional hardwired reliability.

If you want to narrow down the choice, let me know:

• Do you prefer a plug-in, battery-operated, or hardwired model?
• Do you want a combination smoke and CO detector or a dedicated CO-only unit?
• Are you looking for smart features (app alerts)?

The "best" carbon monoxide (CO) detector depends on whether you want a standalone sensor, a smart-home integrated unit, or a dual smoke-and-CO combo . Top choices from safety and consumer testing authorities feature reliable electrochemical sensors and UL certification:

A top pick from The New York Times - Wirecutter , this hardwired combo unit provides dual protection, integrates with smart assistants like Alexa and Google Home, and sends immediate mobile app notifications if an issue arises.

Excellent if you prefer a standalone, maintenance-free option without hardwiring. It features a sealed 10-year lithium battery that eliminates the annoyance of annual battery changes and reliable electrochemical sensing.

Ideal for placement at eye-level or near specific fuel-burning appliances (like a furnace or water heater). It plugs directly into a wall outlet, includes a digital readout showing real-time CO levels, and has a battery backup for power outages.

A popular standalone budget-to-midrange choice featuring a clear LCD screen displaying ambient CO concentration and an ultra-sensitive electrochemical sensor designed to minimize false alarms.

What to Look For:

1. Certification: Always make sure the device is UL-certified (meets UL 2034 standards for CO alarms).
2. Power Source: Choose between hardwired (best for new construction or interconnecting all alarms in a home), 10-year sealed battery (set-it-and-forget-it), or plug-in with a battery backup.
3. Interconnectivity: If one alarm goes off, interconnected models trigger all alarms in the house simultaneously—crucial for larger homes.

If you let me know:

• Whether you need a standalone CO detector or a smoke/CO combination unit
• If your home uses hardwired wiring or you prefer battery-operated/plug-in models

I can give you a more tailored recommendation.

For most homes, the best carbon monoxide (CO) detector is a 10-year, UL-listed model with an electrochemical sensor. The “best” choice depends on whether you want simple protection, smart alerts, or a smoke + CO combo.

Best overall: Kidde 10-Year Battery CO Detector with Digital Display

• Kidde C3010-D Carbon Monoxide Detector with Digital Display - $44.94 (Walmart)
• Kidde 10-Year Battery Carbon Monoxide Detector with Low-Level CO Alerts and Digital Backlit Display - $54.97 (The Home Depot)

Why it’s a strong pick:

• 10-year sealed battery (no annual battery changes)
• Digital CO readout
• Loud alarm
• Easy installation
• Good value for most households

Best smart CO detector: Google Nest Protect

• Google Nest Protect Smoke & Carbon Monoxide Alarm - $149.00 (Walmart)

Best if you want:

• Phone alerts
• Voice warnings that identify the problem and location
• Integration with a smart home setup

It costs more than basic detectors, but it adds convenience and better awareness when you’re away.

Best budget option: First Alert CO615

A good inexpensive choice if you want a reliable standalone CO alarm. Consumer Reports lists the First Alert CO615 among its recommended standalone CO detectors.

Best if you also need smoke protection

Consider a combination smoke + CO alarm, such as Kidde or First Alert models. Combination units can simplify installation, but make sure the smoke technology fits your needs (for example, many experts prefer photoelectric smoke sensing for smoldering fires). Consumer Reports’ testing includes several highly rated combination models.

What I would buy for a typical house

• Bedrooms/hallways: Kidde 10-year CO detectors (one outside each sleeping area and at least one on each level)
• Smart-home users: Google Nest Protect
• Renters: Plug-in model with battery backup

Look for:

• ✅ UL 2034 certification
• ✅ Electrochemical CO sensor
• ✅ End-of-life warning
• ✅ Backup power (if plug-in or hardwired)
• ✅ Replacement after about 10 years (most units expire)

If you tell me whether you live in a house, apartment, RV, or have gas appliances/fireplace, I can narrow it down to the best setup.

What I would buy for a typical house

The best carbon monoxide detector for most people is the Kidde Nighthawk Plug-In Carbon Monoxide Alarm Go to product viewer dialog for this item. . Highly rated across major testing platforms like The Spruce , it combines a reliable electrochemical sensor with a built-in digital screen that tracks current and peak CO levels down to low thresholds. [1][2]

Because carbon monoxide (CO) safety needs vary based on your home setup, the top choices are categorized below by their primary use case:

Best Traditional & Plug-In Detectors

• Best Overall : Widely praised for its simple setup and continuous monitoring via a reliable AC wall plug.

• Standout Feature : Features a digital display that updates every 15 seconds and records "peak memory" levels. It has a 9V battery backup to keep it working during power failures. [1][2]

• Runner-Up : Highly recommended by experts from CNET and Wirecutter as a staple, easy-to-use plug-in option.

• Standout Feature : Includes a clear backlit display and a quick test/silence button. [1][2]

• Best Long-Life Battery : Ideal for rooms lacking wall outlet space or for anyone who hates midnight battery chirps.

• Standout Feature : Powered by a sealed lithium battery that completely eliminates maintenance for a full 10-year lifespan. [1][2]

Best Smart & Combination Detectors

• Best Smart Pick : Perfect for modern smart homes and monitoring properties while away.

• Standout Feature : Offers 2.4 GHz Wi-Fi app alerts (no subscription required) alongside low-level CO tracking. It doubles as an indoor air quality monitor measuring TVOCs, humidity, and temperature.[1]

• Best Smoke/CO Combo : Strongly endorsed by NYT Wirecutter if you need to upgrade your entire ceiling layout.

• Standout Feature : Features voice alerts that call out the specific type and room location of the hazard. Multiple units can wirelessly interconnect so that if one alarm triggers, they all sound.

Best Portable Detector for Travel

• Best for Travel : Named the definitive travel essential by Wirecutter to safeguard against faulty hotel or rental property heaters.
• Standout Feature : Weighs under half a pound and operates entirely on a 10-year lithium battery, meaning you don't need international wall adapters.

To narrow this down, are you looking for a standalone CO detector or a smoke/CO combination unit ? Let me know if you prefer a plug-in, battery-only, or hardwired installation.

For most homes, the best carbon monoxide (CO) detector is the Kidde 10-Year Battery Carbon Monoxide Detector with Digital Display. It offers the features that matter most: a reliable electrochemical CO sensor, a long-life sealed battery, and a digital readout showing CO levels. Independent testing and reviews commonly highlight Kidde and First Alert models as strong choices.

Top picks by situation

• Best overall: Kidde 10-Year Battery Carbon Monoxide Detector with Digital Display

• Best for: most homeowners and renters

• Pros: 10-year sealed battery, no battery changes, digital CO level display, loud alarm

• Cons: no smartphone alerts

• Best smart CO detector: Google Nest Protect

• Best for: people who want phone notifications and smart-home integration

• Pros: voice alerts, app notifications, smoke + CO detection in one device

• Cons: higher price; it is a combination smoke/CO alarm rather than a simple CO-only detector

• Best plug-in option: Kidde Plug-In Carbon Monoxide Detector with Battery Backup

• Best for: quick installation near bedrooms or fuel-burning appliances

• Pros: outlet power plus battery backup, simple setup, affordable

• Best combination smoke + CO alarm: First Alert SC5

• Best for: replacing old smoke alarms while adding CO protection

• Pros: combines both protections and offers smart features depending on model

What to look for

• ✅ UL 2034 certification (important safety standard for residential CO alarms)
• ✅ Electrochemical sensor (the common sensor technology used in quality home CO alarms)
• ✅ 10-year lifespan (many alarms must be replaced after this period)
• ✅ Battery backup if it plugs in
• ✅ Digital display if you want to see low-level CO readings

Placement

Install CO alarms:

• Outside each sleeping area
• On every level of the home
• Near (but not directly above) fuel-burning appliances such as furnaces, fireplaces, or gas water heaters

If you only buy one, I’d choose the Kidde 10-Year Battery Digital CO Detector for most households. If you already have a smart home setup or want alerts while away, choose a smart model like Nest Protect.

If you want one excellent CO detector for a typical home, I’d choose the Kidde 10-Year Battery Carbon Monoxide Detector with Digital Display. It uses an electrochemical sensor, has an 85 dB alarm, a digital CO readout, and a sealed 10-year battery—so there’s very little maintenance. Current testing/reviews also consistently put Kidde among the strongest standalone options.

• Kidde 10-Year Battery Carbon Monoxide Detector with Digital Display - $51.97 (The Home Depot)

My picks

• 🏆 Best overall: Kidde COBD10 — 10-year battery + digital display. Great "install it and forget it" option.

• 💰 Best inexpensive: Kidde plug-in CO detector with battery backup — inexpensive, simple, and continues working during a power outage.

• 📱 Best smart: Kidde COPDW Smart CO Detector — sends real-time phone alerts through the Kidde app without a subscription.

• 🔥 Best smoke + CO combination: First Alert 10-Year Smoke & CO detector — useful if you're replacing smoke alarms too.

• Kidde 10-Year Battery CO Detector with Digital Display - $51.97 (The Home Depot)

• Kidde Plug-In CO Detector with Battery Backup - $34.97 (The Home Depot)

• Kidde Smart Plug-In CO Detector - $56.97 (The Home Depot)

• First Alert 10-Year Smoke & CO Detector - $46.32 (Walmart)

One important point: look for UL 2034 certification and preferably an electrochemical sensor. Also, don't rely on just one detector—CO alarms should generally be installed outside sleeping areas and on every level of the home.

If you tell me whether you want CO-only or smoke+CO, and your budget (e.g. under $30, $50, or $100), I can narrow it down to the single best model for you.

The Kidde Nighthawk Plug-In Carbon Monoxide Alarm is widely considered the best overall choice by home safety experts due to its reliable UL 2034 certification , peak level memory display, and a 9V battery backup that provides continuous protection during power outages.[1]

Because the ideal detector depends on whether you prefer a plug-in model, a standalone battery unit, a smart home integrated system, or a travel option, the top-rated models span several categories:

Top Carbon Monoxide Detectors

Add to list

• Best Overall : Extremely popular plug-in model that tracks peak CO levels from 30 to 999 ppm on a clear digital readout.
• Key Features : Continuous 120V AC power, 9V battery backup, and flexible mounting options using a 6-foot extension cord or direct outlet placement.[1]

Add to list

• Best Smart : Top plug-in choice for tech-heavy setups, integrating seamlessly with Google Home and Amazon Alexa.
• Key Features : Tracks TVOCs, temperature, and humidity alongside carbon monoxide, sending real-time push alerts to your phone via Wi-Fi. [1][2]

Add to list

• Best Standalone Battery : Compact tabletop or wall-mounted unit that doesn't sap outlet space and runs flawlessly without wiring.
• Key Features : Features a sealed 10-year lithium battery to prevent midnight low-battery chirps and displays ambient room temperature alongside peak gas history. [1][2]

First Alert Carbon Monoxide Alarm CO710XP:

• Best for Travel : Heavily recommended by NYT Wirecutter as a packable, travel-sized lifesaver.
• Key Features : Weighs under half a pound, slides easily into a carry-on suitcase, and runs on a 10-year internal battery so you don't need international wall adapters.

Important Selection Tips

• Verify Certifications : Ensure any model you purchase carries a UL Solutions or Intertek mark to prove it undergoes rigorous, independent third-party safety testing.
• Look for Digital Displays : Opt for units with a digital PPM (parts per million) screen . This allows you to check if lower, non-lethal amounts of gas are slowly building up before the actual 85 dB siren is triggered. [1][2][3]

If you would like to find the exact match for your home layout, let me know:

• Do you want a standalone CO detector or a combination smoke/CO alarm?
• Are your existing alarms hardwired into the ceiling, or do you prefer plug-in / battery units?
• Do you require smart connectivity to receive phone alerts when you are away from home?

The "best" carbon monoxide (CO) detector depends on whether you want a simple standalone unit, a digital readout, a travel companion, or an interconnected smart home system. Major safety organizations like Consumer Reports and Wirecutter emphasize choosing models from trusted brands that strictly comply with UL (Underwriters Laboratories) standards.

Top-rated carbon monoxide detectors fall into distinct categories based on your needs:

Add to listBest Plug-In with Digital Readout: Kidde Nighthawk Plug-In CO Alarm (KN-COPP-3)Go to product viewer dialog for this item.

• Why it’s great: It plugs directly into a standard wall outlet (or sits on a tabletop with an optional cord) and features a digital LCD screen that continuously displays CO levels in parts per million (PPM). It also includes a battery backup for power outages and a peak-level memory button to show the highest concentration recorded.[1]

Add to listBest Standalone Battery-Operated Unit: First Alert CO710 Go to product viewer dialog for this item.

• Why it’s great: A slim, highly portable, and reliable battery-operated alarm that uses an electrochemical CO sensor. It's great for mounting on a wall or placing on a shelf without needing to worry about wiring or taking up an outlet.

Add to listBest 10-Year Sealed Battery / Low-Maintenance Option: Knox Safety 10-Year Battery-Operated CO Detector Go to product viewer dialog for this item.

• Why it’s great: Features a 10-year sealed lithium battery that eliminates the annoying yearly battery-change chirp. It includes voice alerts that clearly state the type of danger alongside a digital display.

Add to listBest Smart Combination Alarm: Kidde Smart Smoke + Carbon Monoxide Alarm Go to product viewer dialog for this item.

• Why it’s great: If you prefer a 2-in-1 device that protects against both fire and CO, this smart option ties into your home Wi-Fi to push instant alerts directly to your smartphone if an emergency occurs, even when you're away.

Add to listBest Portable/Travel Option: First Alert CO710 (Travel Version)Go to product viewer dialog for this item.

• Why it’s great: Compact and lightweight enough to slip into a suitcase or carry-on pocket, making it ideal for checking safety in older hotels, cabins, or rentals.

To help narrow down the ideal choice, let me know:

• Do you prefer a plug-in model or a battery-operated one?
• Are you looking for a standalone CO detector or a combination smoke and CO alarm?
• Do you want smart features (like phone notifications)?

If you want one recommendation for most homes, I’d buy the Kidde 10-Year CO Detector with Digital Display (COBD10/COBDL10).

• Kidde 10-Year Battery Carbon Monoxide Detector with Digital Display - $51.97 (The Home Depot)

Why I like it

• 10-year battery — no routine battery replacement.
• Digital CO readout so you can see the detected level rather than just hearing an alarm.
• 85 dB alarm.
• The COBDL10 version adds low-level CO alerts, which is a worthwhile upgrade if you want earlier warning.
• Current independent reviews generally favor Kidde and First Alert; Consumer Reports' 2026 testing ranked the First Alert CO615 highest among the standalone CO detectors it tested, with Kidde models also performing well.

My picks by situation

• Kidde COBDL10 — best for low-level CO detection - $54.97 (The Home Depot)
• Kidde COBD10 — best overall value - $51.97 (The Home Depot)
• Kidde COPDW — best smart/app-connected option - $56.97 (The Home Depot)
• First Alert CO710 — excellent 10-year alternative - $44.99 (Target)

For a normal house: COBD10 or COBDL10. Want phone notifications: Kidde COPDW. Want inexpensive and simple: a basic Kidde plug-in with battery backup. Need smoke + CO in one unit: consider a 10-year combination alarm instead.

One important point: don't buy just one for the house. CO alarms should be installed on every level and near sleeping areas. Also look for UL 2034 certification on the specific model.

If you tell me whether you want CO-only or smoke+CO, and your budget (e.g. under $30, $50, or $100), I can narrow it down to the exact model I'd buy.