Three best carbon monoxide detectors

Michael Pollick

Experts recommend installing at least one carbon monoxide detector on each level of your home, plus additional alarms near gas-powered appliances and enclosed garages.

Carbon monoxide (CO) is an odorless, tasteless, invisible, and deadly gas. The best way for homeowners to detect this toxic gas is with carbon monoxide detectors. The best CO detectors measure the CO concentration level in the air and display the results on easy-to-read digital panels. Safety experts recommend installing at least one CO detector on each level of your home. These alarms should also be placed in areas where natural CO generation is possible, such as the garage, kitchen, furnace room, or laundry room. Carbon monoxide detectors are relatively inexpensive, easy to maintain, and work well in conjunction with smoke and fire detectors. This quick guide has everything you need to know when buying CO detectors, including our picks for the three best on the market.

Considerations when choosing carbon monoxide detectors


Most carbon monoxide detectors use electrochemical technology to analyze the concentration levels of CO. The chemicals used to detect and measure CO have a finite lifespan. This means all carbon monoxide detectors will eventually need to be replaced. Look for models with at least five years of guaranteed performance.

CO monitoring

There are two different types of CO toxicity that a good carbon monoxide detector should monitor. The first is a sudden spike in CO levels. Long-term exposure to lower CO concentrations is also hazardous to humans and pets, so a good CO detector should also alert homeowners to low-level CO exposure.

Power source

The least expensive carbon monoxide detectors tend to use batteries as their primary power source, which usually must be changed or recharged regularly. Other detectors are plugged into standard outlets and may use batteries as backup power. Higher-end CO detectors, especially those used as part of a smart alarm system, are hardwired directly into your home's wiring.


There are several features to look for when shopping for carbon monoxide detectors.


A CO detector should be in a constant state of analysis. Many models monitor the surrounding air every 15 seconds for carbon monoxide and display the results in parts per million (ppm). This is the most vital number a homeowner needs to see. Some units also display the highest and lowest recorded readings over a specified time. The battery's charge may also be displayed.


The alarm on a carbon monoxide detector should blare just as loudly as a smoke detector. Testing the alarm periodically is always a good idea.

Adjustable settings

Some CO detectors can be overly sensitive or not sensitive enough when it comes to analyzing CO levels. Homeowners may need to make a few adjustments in order to prevent false positives or undetected CO spikes. A good CO detector should allow users to set their own thresholds within reason. A qualified utility company representative may be able to test the installed system and recalibrate it if required.


The cost of a carbon monoxide detector varies widely from model to model, but much of the price difference is found in features, not performance. Quality home carbon monoxide detectors usually cost between $25 and $50. The highest-end CO detectors tend to be part of a larger smart alarm system or used by professionals to monitor work areas or detect CO levels for others.


Q. I just purchased three carbon monoxide detectors for my new home. Where should I install them?

A. The placement of CO detectors is always an important consideration. One good location is in the kitchen, especially near any gas-powered appliances. An enclosed garage with a water heater or vehicles is also a potential CO hot spot. Many homeowners also place a CO detector near bedrooms.

Q. I live in an apartment with all electric appliances. Do I still need to install a CO detector?

A. Although carbon monoxide poisoning is more closely associated with other types of power, such as natural gas or heating oil, it can also be found in homes that use electric power. Carbon monoxide is odorless and colorless, and it can build up as a result of heat radiation from an electric stove or water heater. Ventilation issues can also cause a CO build-up, so we strongly recommend installing at least one CO detector in an all-electric home for better peace of mind.

Q. What are the symptoms of carbon monoxide poisoning?

A. The symptoms of carbon monoxide poisoning are often described as flu-like, so many people may ignore them. The most common CO poisoning symptoms are sudden headache, dizziness, nausea, and vomiting. Younger children and the elderly are more vulnerable to the effects of low-level CO exposure, but healthy adults can still become very ill when higher CO concentrations (over 450 ppm) are present in the home.

Carbon monoxide detectors we recommend

Best of the best: Nest Protect Smart Smoke and Carbon Monoxide Alarm, 2nd Generation 

Our take: The Nest Protect detector may be an investment, but its dual functionality and smart technology make it an ideal choice for new homes.

What we like: This CO detector is extremely durable, with a lifespan of 10-plus years. It measures both short-term and long-term CO exposure and offers interconnectivity with other Nest products.

What we dislike: Carbon monoxide concentration is not displayed in ppm. The smoke detector is emphasized over CO function.

Best bang for the buck: First Alert Dual Power Carbon Monoxide Alarm 

Our take: This CO detector is an affordable investment for homeowners and landlords who need to install multiple units on different floors.

What we like: It works with both electrical and battery power and features continuous electrochemical CO sampling and an end-of-lifespan alarm.

What we dislike: The alarm can be difficult to hear, especially when detecting lower CO levels.

Choice 3: Kidde Battery Power Carbon Monoxide Alarm with Digital Display 

Our take: For those seeking a low-maintenance CO detector, this Kidde detector is designed to set it and forget it.

What we like: It includes a 10-year warranty on the sealed lithium battery. The alarm is quite loud, and readings are updated every 15 seconds. A mounting bracket is included.

What we dislike: Some battery malfunctions have been reported. High humidity can trigger a false positive reading for CO. Readings don't start until 30 ppm.

Michael Pollick is a writer for BestReviews. BestReviews is a product review company with a singular mission: to help simplify your purchasing decisions and save you time and money. BestReviews never accepts free products from manufacturers and purchases every product it reviews with its own funds.

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