Carbon monoxide (CO) is the leading cause of poisoning deaths in the United States. Every year, this odorless, colorless gas kills more than 400 Americans, hospitalizes more than 4,000, and sends 20,000 to the emergency room, according to the Centers for Disease Control and Prevention (CDC)1. At first, CO poisoning symptoms seem like the flu—headache, dizziness, weakness, nausea, and vomiting—but people who are sleeping or intoxicated can die from CO poisoning before they show any symptoms2.
Just like a smoke detector warns you of fire, a CO detector warns you of high carbon monoxide levels. A standalone CO detector is particularly useful in areas susceptible to CO buildup, like your garage or RV and near fuel-burning furnaces, stoves, water heaters, fireplaces, and generators.
We’ll help you find the best CO detector to protect your home from this potentially deadly threat.
Our top 5 picks
#1 Kidde KN-COPF-i Silhouette
We ranked the Kidde Silhouette first because we love the ease and added safety of integrating this CO detector with other Kidde CO detectors and smoke alarms throughout your house.
Once integrated, all the alarms in your house will sound if one detector goes off. Only the triggered alarm will flash, though, so you can quickly identify the problem area. With the Silhouette, you can view a history of CO levels in your home on the digital display, and the self-charging backup battery means you don’t need to worry about power outages or replacing batteries for the seven-year product life. The Silhouette protrudes only about an inch from the wall, making it less obtrusive than most other detectors.
Pricing & tech specs
- MSRP: $74.99
- Size: 4.8” x 4.8” x 1.5”
- AC powered
- 7-year warranty
Pros
- Interconnectable system
- Digital display
- Updates every 15 seconds
- Stores peak CO levels
- Hardwired
- Rechargeable backup battery
- Audible 85-decibel alarm
- 7-year warranty
Cons
- Requires installation
- No dimming option on LED display
#2 First Alert CO710
Even though the First Alert CO710 detector is battery powered, the 10-year lithium battery means you don’t need to worry about buying new batteries every year. You won’t need to hear that annoying low-battery chirp or worry about installing it near an electrical outlet, either. However, the lithium battery also can’t be replaced, which means you will need to buy a new detector every 10 years. The detector’s compact design sits on a table or mounts on a wall, so you can place it wherever you need it most.
The backlit digital display shows the ambient room temperature during standby mode, while CO levels will be displayed during testing and the peak level feature will display the highest concentration of CO measured by the detector during the past 24 hours. If the sensor detects high levels of carbon monoxide, an alarm will sound and the backlight will glow.
Pricing & tech specs
- MSRP: $59.95
- Size: 0.9” x 4.8” x 2.6”
- Battery powered
- 10-year warranty
Pros
- 10-year lithium battery
- Freestanding or wall mounted
- Digital display
- Stores peak CO levels for 24 hours
- Monitors room temperature
- Audible 85-decibel alarm and visual backlight alarm
- 10-year warranty
- End-of-life warning
Cons
- Can’t replace battery
- No hardwiring
#3 Kidde KN-COPP-B-LPM
The Kidde KN-COPP-B-LPM offers essential security features without breaking the bank. Like the Silhouette and CO710, the Kidde stores CO level readings for you to review and includes a digital display—it updates its reading every 15 seconds and stores peak CO levels since the last reset.
The major drawback to this detector is that it does not detect non-alarm levels of CO, which can still be harmful if sustained for long periods of time. However, the Kidde gives you reliable safety at a more affordable price—especially if you plan to buy several CO detectors—and has high customer reviews, which is why it made our top five.
Pricing & tech specs
- MSRP: $34.99
- AC powered
- 10-year warranty
Pros
- Inexpensive
- Digital display
- Updates every 15 seconds
- Stores peak CO levels
- Low-battery alerts
- Battery safeguard cover
- Audible 85-decibel alarm
- LED light to indicate status (green for normal, red for alarm)
- 10-year life
Cons
- Does not alert user to long-term low levels of CO
- No hardwiring
- Should not be used with rechargeable batteries
#4 First Alert Onelink GLOCO Wi-Fi Environment Monitor
The First Alert Onelink GLOCO Wi-Fi Environment Monitor is one of the few CO detectors on the market that connects to your smartphone and Apple HomeKit system. This detector sends push notifications to the Onelink app when it detects high levels of CO. It will also alert you if the room’s temperature or humidity changes beyond your preset thresholds. The LED ring changes color to indicate status, making it easy to tell at a glance if something is wrong.
This detector does not have a digital display, and some customer reviews say the Wi-Fi connection is tenuous, which is why this detector is not higher on our list.
Pricing & tech Specs
- MSRP: $125.95
- Size: 2.8” x 2.8” x 3”
- AC powered
- 10-year warranty
Pros
- Apple HomeKit-enabled
- Push notifications from Onelink app
- LED ring to indicate status (white for normal, red for CO, blue for too cold, amber for too warm)
- Backup battery (one CR2 lithium battery)
- Freestanding
- Monitors room temperature and humidity
- Audible and visual alarm
Cons
- No digital display
- Requires Wi-Fi connection
- No hardwiring
#5 Sensorcon CO Inspector
While the Sensorcon CO Inspector is not ideal for home use, it is our top pick for portable, on-the-go CO monitoring. This detector will help keep you safe on construction sites or while you travel. The two-year battery life is a slight drawback, but its protective case will keep it safe from water, dust, and impact during that time. With a visual, audio, and vibrating alarm, you’ll be able to tell if something is wrong no matter where the detector is located.
Pricing & tech specs
- Price: $129.00
- Size: 3.2” x 2.2” x 0.9”
- Battery powered
- 1-year warranty
Pros
- Digital display
- Portable (has attachment clip and lanyard loop)
- Waterproof
- Shockproof
- Dustproof
- Audible, visual, and vibrating alarm
Cons
- 2-year battery life (one CR123A battery)
- 1-year warranty (shorter than other detectors)
- No hardwiring
Things to consider before buying
There are three types of sensors: biometric, semiconductor, and electrochemical. All of our top five CO detectors use electrochemical sensors. This type of sensor is highly accurate, requires minimal power, and operates at room temperature, making it ideal for home use. Biometric sensors are often used in hotels because they will not sound false alarms due to cleaning agents—but they are more expensive than electrochemical alarms. Semiconductor sensors, on the other hand, must be hardwired or plugged in and often sound false alarms3.
When deciding which CO detector to purchase, you should consider price, power source, and location. With a plug-in detector, you don’t need to check or replace the battery. However, if the plug-in detector does not have a backup battery, it will stop working during a power outage. Hardwired detectors can integrate into your existing safety system, but they are not portable and may require a contractor to install. Some detectors can sit on a table anywhere, while others need to be drilled into the wall.
Keep your family safe
Carbon monoxide can kill without giving you any warning. Properly installed CO detectors, along with smoke detectors, are a critical part of your home safety system.
To keep your family safe, install CO detectors on every level of your house, paying special attention to your kitchen, garage, and basement, where carbon monoxide can accumulate.
If you install a detector that requires batteries, check or replace the batteries twice a year (coordinate with daylight saving time in the fall and spring so you don’t forget). Make note of the installation date and lifespan of your detector so you replace it frequently enough.
Whether you decide to integrate the hardwired Kidde Silhouette detector into your existing home safety system (our recommendation) or set the affordable Kidde KN-COPP-B-LPM on a side table, it’s important to start monitoring the CO levels in your home immediately to avoid a buildup of the silent killer.
1. Centers for Disease Control and Prevention, “Carbon Monoxide Poisoning Frequently Asked Questions”
2. American Academy of Pediatrics, “Protecting Children from Carbon Monoxide Poisoning”
3. Engineers Edge, “Carbon Monoxide Sensor Detector Review”