What is the best carbon monoxide detector?

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:

• 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.

Add to listBest Standalone Battery-Operated Unit:

• 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:

• 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:

• 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:

• 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.

If you want one straightforward recommendation, I’d buy the Kidde COBDL10. It combines a 10-year sealed battery, digital display, 85 dB alarm, and low-level CO alerts. It’s also currently highly rated at Home Depot.

• Kidde COBDL10 10-Year CO Detector - $54.97 (The Home Depot)

My top choices

• 🏆 Best overall: Kidde COBDL10 — Best balance of safety features and convenience. The low-level CO alert is a particularly nice feature.

• 💰 Best value: Kidde COBD10 — 10-year battery, digital display, and 85 dB alarm without paying extra for low-level detection.

• 📱 Best smart option: Kidde COPDW — Sends real-time CO alerts to your phone over Wi-Fi, with no subscription required.

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

• 🔌 Best simple plug-in: Kidde Firex — Plug-in power with AA battery backup; inexpensive and highly rated.

• 🥇 Best independently tested basic model: First Alert CO615 — Consumer Reports currently gives it the highest score among the standalone CO detectors it tested (91/100).

• First Alert CO605 Plug-In CO Detector - $23.99 (Target)

What I'd prioritize

Whatever model you buy, look for UL 2034 certification, an electrochemical CO sensor, and preferably a 10-year alarm life. UL 2034 is the relevant U.S. residential CO-alarm standard.

Also, don't rely on just one detector: CO alarms should generally be installed outside sleeping areas and on every level of the home.

Bottom line: For most homes, I'd spend the extra ~$10 and get the Kidde COBDL10 rather than the cheapest detector.

The top choices for monitoring Carbon Dioxide (CO2) are the Aranet4 Home Go to product viewer dialog for this item. for portability and precision, and the Inkbird IAM-T1 Go to product viewer dialog for this item. or Awair Element Go to product viewer dialog for this item. for smart home connectivity and comprehensive indoor air quality tracking.

Note: Make sure you are looking for a Carbon Dioxide (CO2) monitor to measure ventilation and freshness, rather than a Carbon Monoxide (CO) detector, which is a life-safety device designed to alert you to deadly, poisonous heating leaks.

Top Carbon Dioxide (CO2) Monitors

Add to list Widely praised by air quality specialists as the best overall choice due to its highly accurate, battery-operated NDIR (non-dispersive infrared) sensor and e-ink display. It features long battery life, clear visual indicators, and bluetooth capability to track long-term ventilation trends via a mobile app.

Add to list An excellent mid-range electronic option that tracks indoor air metrics seamlessly. It offers strong app connectivity to let you monitor and log your environment's real-time CO2 spikes cleanly.

Add to list A leading plug-in choice for tech-forward users looking for comprehensive data. It pairs accurate NDIR carbon dioxide tracking with sensors for TVOCs, temperature, humidity, and fine particulate matter.

Add to list A fantastic budget-conscious pick that cuts out unnecessary smart bells and whistles to give you immediate, reliable digital readings right from your desk.

Top Carbon Monoxide (CO) Safety Alarms

If you meant a life-saving Carbon Monoxide detector for fires or gas leaks, these are the top safety options recommended by major product testing labs and expert reviewers:

Add to list Top choice for battery-powered smart protection. It blends top-tier life-safety sensor accuracy with integrated Google Home notifications so you can check your status while away.

Add to list A reliable, highly rated choice that plugs straight into a wall outlet. It comes equipped with a digital readout screen and battery backup so it keeps working even if you lose power.

Add to list The premier smart premium option. It features voice-directed alarms that tell you exactly what room the danger is in, and it syncs flawlessly with modern smart home apps.

Could you clarify if you need this device to measure fresh air ventilation (CO2) or to protect against toxic gas leaks (CO) ? Sharing your budget or if you want smart app integrations would help pick the perfect match.

The Kidde Nighthawk AC Plug-In Carbon Monoxide Alarm (KN-COPP-3)Go to product viewer dialog for this item. and the First Alert 10-Year Battery Carbon Monoxide Alarm (CO710)Go to product viewer dialog for this item. are widely considered the best carbon monoxide detectors overall by safety experts and consumer testing platforms. To ensure your safety, it is vital to choose an independently verified model that carries a UL or Intertek certification mark.

The ideal choice depends entirely on how you prefer to power the device, where you plan to install it, and whether you require smart home integration.

Top Carbon Monoxide Detectors

Detailed Product Breakdown

• Features a clear LED digital readout that updates every 15 seconds.

• Retains peak-level memory to track recorded leaks while you were away.

• Plugs directly into the wall or uses a 6-foot cord for tabletop placement.

• Requires absolutely no hardwiring or mounting brackets for installation.

• Offers a compact profile under half a pound, making it perfect for suitcases.

• Delivers a built-in 10-year lifespan without a single battery swap.

• Broadcasts phone notifications during emergencies via 2.4 GHz Wi-Fi.

• Integrates directly into your existing Alexa or Google Home ecosystems.

• Evaluates volatile organic compounds (VOCs) to monitor overall indoor air quality.

• Blasts a loud 85-decibel alarm to wake up deep sleepers during leaks.

• Uses a dedicated Test/Hush button to easily silence false alarms.

• Includes pre-programmed end-of-life reminders exactly 10 years after activation.

Essential Placement Rules

To maximize safety, place detectors on every level of your home and directly outside of all sleeping areas . Always keep them at least 15 feet away from gas-burning appliances to prevent false triggers, and at least 3 feet away from air vents so the gas isn't blown away from the sensor.

To help me narrow down the best model, what power source do you prefer (plug-in, battery, or hardwired)? Are you looking for a standalone CO detector or a combination smoke and CO alarm ? Let me know if you want smart phone alerts.

If you want one excellent carbon monoxide (CO) detector for a typical home, my pick right now is the Kidde C3010D / its current equivalent: a 10-year sealed-battery unit with a digital CO readout. Consumer Reports currently rates it among its top standalone CO detectors.

Kidde 10-Year Battery Carbon Monoxide Detector

$52.97

My top choices

The Kidde COPDW is particularly appealing if you want your phone to alert you when you're away from home; independent testing in 2026 rated it the best budget standalone smart CO detector.

Kidde Plug-In Smart Carbon Monoxide Detector

$56.97

What I'd look for regardless of brand: an electrochemical sensor and UL 2034 certification. Those are more important than fancy smart-home features.

Also, don't just buy one: CO alarms should generally be installed outside each sleeping area and on every level of the home.

If you tell me how many floors you have, whether you have gas/oil/wood heat, and whether you want smoke + CO in the same unit, I can narrow it down to the best 2–3 detectors for your house and find the current prices.

The "best" carbon monoxide (CO) detector depends on whether you need a standard home unit, a smart/connected option, or a portable travel device . Independent testing from experts like Consumer Reports and The New York Times (Wirecutter) highlights several top-performing models across different categories:

• Best Stand-Alone CO Detector (Overall): First Alert CO615 (Plug-In with Battery Backup)Go to product viewer dialog for this item. or First Alert CO710 (10-Year Battery with Digital Display)Go to product viewer dialog for this item. . These models consistently score top marks for fast and accurate response times to both high and low CO concentrations . The CO710 features a sealed 10-year battery, meaning no annoying low-battery chirps for a decade, plus a clear digital temperature and peak-level screen.
• Best Smart CO Detector / Air Quality Monitor: Kidde Smart Carbon Monoxide Alarm with Indoor Air Quality Monitor (COPDLQW)Go to product viewer dialog for this item. . This plug-in smart model tracks low-level CO—ideal for children, the elderly, or pets—and monitors room temperature, humidity, and total volatile organic compounds (TVOCs) while syncing directly to your smartphone via Wi-Fi without requiring a monthly subscription.
• Best Combination Smoke and CO Unit: Kidde Hardwired/Battery Smart Smoke and Carbon Monoxide Detector Go to product viewer dialog for this item. or X-Sense Interconnected Combination Alarms Go to product viewer dialog for this item. . These provide whole-home interconnected safety (if one alarm sounds, they all sound) and beam push notifications directly to your phone if you are away.
• Best Portable / Travel CO Detector: First Alert CO710 or compact travel options like the Lunarlipes Portable CO Detector Go to product viewer dialog for this item. . Because short-term rentals and hotels aren't universally mandated to have well-maintained CO detectors, a lightweight, battery-operated or rechargeable travel unit provides immense peace of mind on the road.

To help narrow down the best choice for you, tell me:

• Do you prefer a plug-in unit or a hardwired/10-year sealed battery model?
• Are you looking for a stand-alone CO detector or a combination smoke/CO alarm?
• Do you want smart phone alerts or a traditional offline alarm?

If you want one excellent CO detector for most homes, I’d pick the Kidde COBDL10.

Kidde 10-Year Battery Carbon Monoxide Detector with Low-Level Alerts

$54.97

Why I like it

• 10-year sealed battery — essentially maintenance-free.
• Digital display shows CO levels rather than simply sounding an alarm.
• Low-level CO alerts, which can warn about smaller concentrations before they reach the levels required to trigger a conventional alarm.
• Uses an electrochemical CO sensor.
• Current price is around $55.

Consumer Reports' 2026 testing also rates Kidde's detectors very highly, including the Kidde P4010DCSCO-W combination unit.

Other good choices

Kidde Smart CO Detector

$56.97

First Alert CO400 2-Pack

$34.99

First Alert CO710

$44.99

Google Nest Protect

$149.00

• Best smart option: Kidde Smart COPDW — sends real-time notifications to your phone without a subscription.
• Best inexpensive option: First Alert CO400 — simple, battery-powered, and inexpensive.
• Best if you also need smoke detection: Google Nest Protect or a highly rated Kidde/First Alert combination alarm.
• Best simple plug-in: First Alert CO615; Consumer Reports gives it the highest score among its standalone CO detectors.

One important thing: look for UL 2034 certification, and ideally put a CO alarm on every level of your home and near sleeping areas. UL 2034 is the recognized residential CO-alarm safety standard.

If you tell me whether you want CO-only vs. smoke+CO, plug-in vs. battery, and your approximate budget, I can narrow it down to the best 2–3 models to buy right now.

When choosing the best carbon monoxide (CO) detector, reliability and certification (such as a UL or ETL safety mark) are paramount . Top safety experts like Consumer Reports and Wirecutter emphasize sticking to trusted brands like Kidde and First Alert rather than obscure off-brand alternatives.

The best carbon monoxide detectors categorized by your specific needs include:

• Best Overall Plug-In: Kidde Nighthawk (KN-COPP-3)Go to product viewer dialog for this item.
  This classic plug-in unit features a digital display showing real-time CO levels in parts per million (PPM) and includes a battery backup so it stays active during power outages.
• Best Smart CO & Air Quality Monitor: Kidde Smart Carbon Monoxide Alarm (COPDLQW)Go to product viewer dialog for this item.
  A brilliant plug-in choice that tracks low-level CO and monitors indoor conditions like humidity, temperature, and TVOCs, sending immediate alerts straight to your phone via Wi-Fi.
• Best Smart Standalone/Combo: First Alert SC5 Smart Smoke and Carbon Monoxide Alarm Go to product viewer dialog for this item.
  An exceptional dual-sensor pick if you want combined smoke and CO tracking with smart-home compatibility and phone notifications when you are away.
• Best Budget / Simple Standalone: First Alert CO400 Go to product viewer dialog for this item.
  A straightforward, battery-operated standalone alarm that is reliable, inexpensive, and doesn't require complicated wiring or setup.
• Best Portable/Travel Option: Lunarlipes Portable Carbon Monoxide Detector (PTH-10D)Go to product viewer dialog for this item.
  Recommended for travel (hotels, Airbnbs, or RVs), this compact, rechargeable unit gives you peace of mind on the road where built-in home alarms aren't guaranteed.

To help narrow down the best option, tell me:

• Are you looking for a standalone CO detector or a combo smoke/CO alarm?
• Do you prefer a plug-in unit , a battery-powered unit , or a smart/Wi-Fi connected model?

The “best” carbon monoxide (CO) detector depends on whether you want maximum safety, smart-home features, or simple reliability. These are the top picks I’d consider:

Kidde Smart Carbon Monoxide Detector (COPDW)

$56.97

Kidde COBDL10 10-Year Battery Carbon Monoxide Detector

$54.97

Google Nest Protect Smoke & Carbon Monoxide Alarm

$149.00

First Alert CO400 Battery-Operated Carbon Monoxide Alarm

$34.99

Best overall for most homes: Kidde Smart CO Detector (COPDW)

• Wi-Fi alerts to your phone
• Battery backup
• Voice alerts that tell you what hazard is detected
• Good choice if you want to know about CO even when you’re away

Best simple, dependable choice: Kidde 10-Year Battery CO Detector

• Sealed 10-year battery (no yearly battery swaps)
• Low-level CO monitoring options on some models
• Digital display models can show CO readings

Best smart-home option: Google Nest Protect

• Detects both smoke and CO
• Sends phone alerts
• Uses voice warnings and can identify the location of the problem if you have multiple units
• More expensive, but excellent for a connected home

Best budget option: First Alert CO400

• Affordable and easy to install
• Uses an electrochemical CO sensor
• Good for adding extra detectors around bedrooms or living areas

What I’d look for before buying

• UL-listed certification (avoid untested generic alarms)
• Electrochemical sensor (the common standard for home CO detection)
• 10-year life if possible
• Digital display if you want to see CO levels
• Battery backup even for plug-in models

For most houses, I’d install:

• 1 detector near sleeping areas
• 1 on each level of the home
• 1 near fuel-burning appliances (but not directly above them)

If you already have smoke alarms, I’d lean toward a CO-only detector; if you’re replacing old alarms, a smoke + CO combination unit is often the better upgrade.