Appliances around your home, such as fireplaces, boilers, and water heaters, can emit carbon monoxide if they don’t fully burn their fuel. Because carbon monoxide (CO) isn’t visible and doesn’t have a smell, you should install carbon monoxide detectors throughout your house to monitor the levels of this gas and improve your home safety.
A carbon monoxide detector should audibly and visually alert you when it detects a dangerous environment, so you can quickly get you and your family to safety. Some carbon monoxide detectors also come with smoke detectors built-in for an all-in-one device. However, base models typically cost around $30–70, with dual models or portable models sometimes ranging from $70–$150.
To help you find the best CO detector for your home, the This Old House team put together this guide to the best detectors on the market. Our choice for the best overall carbon monoxide detector is the First Alert Combination Smoke and Carbon Monoxide Detector for its light indication capability. Read our guide below for more about our top picks.
Top 7 Carbon Monoxide Detectors
- First Alert Combination Smoke and Carbon Monoxide Detector: Best Visual Alerts
- Kidde Smoke & Carbon Monoxide Detector: Best Pack Options
- Kidde Nighthawk Carbon Monoxide Detector: Best Plug-In Detector
- X-Sense Smoke and Carbon Monoxide Detector: Best Lifespan
- Google Nest Protect Smoke Detector and Carbon Monoxide Detector: Best Smart Detector
- First Alert CO710 Carbon Monoxide Detector: Best Compact
- GZAIR Travel Carbon Monoxide Detector: Best Portable
Compare Top Carbon-Monoxide Detectors
| Product | Detection | Alert Type | Design | Warranty |
|---|---|---|---|---|
First Alert Combination Smoke and Carbon Monoxide DetectorCheck Price | Smoke and carbon monoxide | Visual and auditory | Battery-powered | 7 years |
Kidde Smoke & Carbon Monoxide DetectorCheck Price | Smoke and carbon monoxide | Auditory | Battery-powered | 10 years |
Kidde Nighthawk Carbon Monoxide DetectorCheck Price | Carbon monoxide | Visual and auditory | Cord-operated with battery backup | 10 years |
X-Sense Smoke and Carbon Monoxide DetectorCheck Price | Smoke and carbon monoxide | Visual and auditory | Battery-powered | 5 years |
Google Nest Protect Smoke Detector and Carbon Monoxide DetectorCheck Price | Smoke and carbon monoxide | Visual and auditory | Battery-powered | 2 years |
First Alert CO710 Carbon Monoxide DetectorCheck Price | Temperature and carbon monoxide | Visual and auditory | Battery-powered | 10 years |
GZAIR Travel Carbon Monoxide DetectorCheck Price | Carbon monoxide | Visual and auditory | Battery-powered | 1 year |
Best Visual Alerts
First Alert Combination Smoke and Carbon Monoxide Detector
We like that this carbon monoxide alarm offers two-in-one protection against smoke and carbon monoxide. In addition to its test button and silence button, this device has two indicator lights—one for smoke and one for carbon monoxide. When one is detected, its designated light flashes to alert you of the problem. An alarm accompanies the flash unless you silence it with the button.
Pros and Cons of First Alert Combination Smoke and Carbon Monoxide Detector
- Continues to work even if there’s a power outage because it’s battery-operated
- Uses an electrochemical sensor for carbon monoxide and a photoelectric sensor for smoke
- Has three types of beeps—one for detection, one for low battery, and one for end of life
- Doesn’t ship to New York residents
- Some customers received defective ones that died within a few months
What People Are Saying About The First Alert Combination Smoke and Carbon Monoxide Detector
Customer reviews we found said that this detector was easy to install, had a loud alarm, and offered a lot of features. Those who were disappointed with the product said that it malfunctioned after a few months of use.
Best Pack Options
Kidde Smoke & Carbon Monoxide Detector
Our team was impressed to see that this battery-operated device alerts you of smoke and carbon monoxide. The device is UL-certified and includes a 10-year limited warranty. It also comes in larger packs of two, four, and six, allowing you to replace all of the detectors in your home at once.
Pros and Cons of Kidde Smoke & Carbon Monoxide Detector
- Has voice notifications
- Includes a battery backup
- Has photoelectric sensor technology
- Doesn’t have a digital display
- Some customers complained of false alarms
What People Are Saying About The Kidde Smoke & Carbon Monoxide Detector
Customers praised this device’s low noise level, long-lasting battery life and ease of installation. We also noted that those who didn’t enjoy their purchase said that they were missing parts, and others said they had an issue with false alarms going off consistently.
Best Plug-In Detector
Kidde Nighthawk Carbon Monoxide Detector
The Kidde Nighthawk Carbon Monoxide Detector can be plugged into any outlet in your home and moved around as you wish. We like that this UL-certified device has a digital display to show you the carbon monoxide level in your room as well as a backup battery to ensure that it continues to function in the event of a power outage.
Pros and Cons of Kidde Nighthawk Carbon Monoxide Detector
- Has an LED display that gives you a reading of your room’s carbon monoxide level
- Features a test button to make sure that the detector is working
- Comes with a 10-year warranty
- Doesn’t detect smoke along with carbon monoxide like the other models in this review
- Some customers said they received faulty models
What People Are Saying About The Kidde Nighthawk Carbon Monoxide Detector
Our research showed that customers who left poitive reviews for this carbon monoxide detector said that it was easy to install and provided peace of mind. However, some reviewers had difficulty utilizing the manufacturer’s limited warranty.
Best Lifespan
X-Sense Smoke and Carbon Monoxide Detector
This device protects your home from both smoke and carbon monoxide. Our team liked that it features a screen that shows you your carbon monoxide level in parts per million, an LED light that flashes red when a dangerous level is detected, and an alarm that starts when a contaminant is found in the air. All of these features are powered by a 10-year battery.
Pros and Cons of X-Sense Smoke and Carbon Monoxide Detector
- Can be purchased in other packs with more than one detector
- Its digital display tells you the charge of the battery
- Has an LED light that changes color based on what it detects
- May be difficult to read the screen depending on how high your ceilings are
- Can go off even when there aren’t contaminants in the air
What People Are Saying About The X-Sense Smoke and Carbon Monoxide Detector
Most reviewers we found were satisfied with the detector, saying that it was well-made and a good value. A lot of customers appreciated the light indicator that was paired with the alarm. Those who were unsatisfied with their purchase said that mounting the device to a wall.
Best Smart Detector
Google Nest Protect Smoke Detector and Carbon Monoxide Detector
This device has a sleek, modern design and connects to your smartphone making it perfect for smart homes. We found that the manufacturer’s app offers an array of features, such as a reminder when the battery is low and an alert when the carbon monoxide level is high. The body of the device also has a built-in nightlight that activates when you walk under it.
Pros and Cons of Google Nest Protect Smoke Detector and Carbon Monoxide Detector
- Available in battery-powered and hardwired versions
- Can silence the smoke alarm from the mobile app if there’s only a little smoke
- Lights up when you walk by it to help you see where you’re going
- Has a high price point
- Takes longer to set up because it requires connecting it to the internet and downloading an app
What People Are Saying About The Google Nest Protect Smoke Detector and Carbon Monoxide Detector
Several customers we found said that they loved the design, light feature, and motion detection of this device. We also noted that some of those who were unsatisfied with their purchase said that it was more difficult to install than basic devices because of the smartphone setup.
Best Compact
First Alert CO710 Carbon Monoxide Detector
This compact carbon monoxide detector has a large digital display so you can quickly and easily read your home’s temperature and CO2 levels. This product also comes with a built-in 10-year lithium battery and a loud 85-decibel alarm system that alerts you when your CO2 has reached a danger level.
Pros and Cons of First Alert CO710 Carbon Monoxide Detector
- Features a backlit digital digital
- Has a loud 85-decibel alarm when danger level is reached
- Comes with a 10-year lithium battery
- Mounting holes don’t always match previous First Alert models
- Some customers said the battery ran out before the 10 years it advertises
What People Are Saying About The First Alert CO710 Carbon Monoxide Detector
We noted that customers who gave this product positive reviews liked that it had easy installation, and was perfect for small spaces. Several others liked that it had a 10-year battery. However, some reviewers did feel that the display was not large enough, and others found it difficult to display PPM numbers.
Best Portable
GZAIR Travel Carbon Monoxide Detector
If you’re traveling to somewhere that doesn’t have a carbon monoxide detector installed, such as a car, RV, or home rental, this handy device will help give you peace of mind. This travel-sized detector uses an electrochemical sensor to detect the CO levels in real-time, and is fully waterproof and shockproof for added safety.
Pros and Cons of GZAIR Travel Carbon Monoxide Detector
- Is lightweight and comes with a lanyard for easy transport
- Includes a backlit display that shows 0-1,000 PPM
- Has built-in battery that can last for up to two years
- Not designed for whole home use
- Has a high price point
What People Are Saying About The GZAIR Travel Carbon Monoxide Detector
Our research showed that several reviewers who liked this carbon monoxide detector were impressed with its easy portability and straightforward setup. Others were impressed with its vibration alert system when CO was detected. However, there were some reviewers who felt that swapping the battery was challenging and that it didn’t always reset properly after sensing exposure.
What Are the Biggest Factors When Buying a Carbon Monoxide Detector?
Not every carbon monoxide detector is the same, and the best model for your home will depend on what features are most important to you. Some things you should keep an eye on are the power source of the device, its functionality, alert volume and display, and interconnectivity. Read our buying guide below for more information about carbon monoxide detectors.
Power Source
Carbon monoxide detectors are either battery-operated, plug-in, or hardwired.
- Battery: These detectors work even if your power goes out because they run on standard AA batteries or AAA batteries. However, the batteries only last about a year before they need to be replaced. The device will usually chirp to tell you when you have low battery. Occasionally, battery-operated detectors will use lithium batteries, which don’t need to be changed since they last for the entire lifespan of the detector.
- Plug-in: Plug-in models plug into an outlet. They usually come with a battery backup to continue working during a power outage.
- Hardwired: This type of detector is hardwired to your home’s circuitry. Similar to plug-in models, hardwired carbon monoxide models don’t work during power outages unless they have a battery backup.
Function
Most smoke alarms detect more than just carbon monoxide. The most common second function you’ll find in a carbon monoxide detector is smoke and fire detection, but you can also find devices that detect natural gas.
Display
Some detectors have a digital display that allows you to determine if there’s any carbon monoxide in your home, even if it’s a small amount that won’t hurt you. If your carbon monoxide detector doesn’t have a digital display, it’ll likely beep when the level of carbon monoxide in the air reaches a dangerous level.
Alert Volume
The CO detector should be loud enough to wake you up and to be heard from every part of the home, particularly in sleeping areas whenever there is a detection of CO poisoning. Most detectors have a CO alarm that’s at least 85 decibels. However, the alarm will be quieter from across the home, which is why it’s important to have more than one installed. Some alarms also include voice alerts notifications that describe what the specific alarm is.
Interconnectivity
As previously mentioned, you’ll need to install several carbon monoxide detectors in your home if it’s relatively large. This will help you hear the alarm from anywhere in your home and ensure that you’re getting accurate carbon monoxide readings throughout your home. If you purchase several of the same model, you’ll be able to connect the devices to ensure that if one detects carbon monoxide, all of them will beep to alert you.
Lifespan
The sensors in your detector will typically wear out after five to 10 years. Consider replacing your device around this timeframe.
What Could Cause a Carbon Monoxide Leak?
There are numerous things in and around your home that could lead to a carbon monoxide leak, making it even more essential to stay well-equipped with a high-quality, working carbon monoxide detector. Here are some of the biggest reasons why a carbon monoxide leak could occur.
- Faulty or poorly maintained appliances: Gas-powered furnaces, water heaters, stoves, ovens, fireplaces, and other fuel-burning appliances can release carbon monoxide if they are malfunctioning or not properly maintained. The most frequent cause is due to issues with ventilation, burner problems, or blocked exhaust flues.
- Inadequate ventilation: Proper ventilation is crucial for removing combustion byproducts, including carbon monoxide, from indoor spaces. If a home’s ventilation system is not functioning correctly or if there are obstructions in vents, CO can build up indoors.
- Cracked or damaged heat exchangers: In gas furnaces, heat exchangers are designed to separate combustion gases from the heated air circulated through the home. If the heat exchanger is cracked or damaged, it can allow carbon monoxide to mix with the indoor air.
- Blocked chimneys or flues: Chimneys and flues are responsible for venting exhaust gases safely to the outside of your home. If they become blocked or clogged with debris, it can cause a backdraft, allowing carbon monoxide to enter the living spaces.
- Using outdoor equipment inside: Using generators, grills, or other gasoline-powered equipment indoors or in enclosed spaces can produce high levels of CO. These items should always be used outdoors in well-ventilated areas.
- Vehicle exhaust in attached garages: When a vehicle is left running in an attached garage, carbon monoxide can seep into the living areas of the house. It is essential to open the garage door before starting the car and to avoid running vehicles inside the garage.
Frequently Asked Questions About Carbon Monoxide Detectors
Who is at risk of carbon monoxide poisoning?
If you have a carbon monoxide leak in your home, infants, young children, the elderly, and people with chronic heart disease, anemia, or respiratory problems are at a higher risk of carbon monoxide poisoning.
What are the symptoms of carbon monoxide poisoning?
Symptoms of carbon monoxide poisoning look similar to those of the flu. You may experience the following if you’re exposed to high CO levels.
- Dizziness
- Weakness
- Headache
- Upset stomach
- Vomiting
- Chest pain
- Confusion/disorientation
Am I supposed to test my carbon monoxide detector?
Yes. You should test your detector at least once a month. Most models will have a button on them that you can press. When you press that button, the device should sound the same alarm that would go off if carbon monoxide is detected.
Where should I put my carbon monoxide detectors?
You should have a carbon monoxide detector on every floor of your home and 15–20 feet from your furnace or another fuel-burning heat source. If you want more protection, you can place a carbon monoxide detector outside of every bedroom.
Why Trust The This Old House Team
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We recommend products in each review using an intensive research process, spending hours combing through the best available models on Amazon. For a product to make our list of top picks, it must hold a solid sales record on Amazon, have consistently positive customer reviews, and offer unique features, among other factors. After narrowing down our list of recommendations, we conduct additional research and sometimes in-person testing to ensure that the products meet our standards. Once we conclude the research phase, we craft a well-rounded, user-friendly article that includes our recommended products and additional information to help homeowners like you make the right purchase.