Can Smoke Detectors Detect Carbon Monoxide: Know The Facts

Smoke detectors have been long revered as cautious guardians against the perilous threat of fires. Their timely alerts have saved countless lives and properties over the years. 

Yet, amidst this commendable reputation, a question lingers, can smoke detectors detect carbon monoxide? 

No, smoke detectors cannot detect carbon monoxide. They are designed to sense smoke particles, indicating a potential fire. For carbon monoxide detection, a separate carbon monoxide detector with specific sensors is required.

Let me shed light on the question and explain why your regular smoke detectors cannot detect carbon monoxide and what good alternative options you have to do the job.

Can Smoke Detectors Detect Carbon Monoxide

Why Can’t Smoke Detectors Detect Carbon Monoxide?

There are several reasons for your smoke detectors’ failure to detect carbon monoxide. Some of the major reasons include;

Detection Mechanisms

Smoke detectors operate using photoelectric or ionization technology. Photoelectric smoke detectors utilize a light source and a light-sensitive sensor. When smoke enters the detector chamber, it scatters the light, triggering the alarm. Ionization smoke detectors, on the other hand, ionize the air inside the detector using a small radioactive source. Smoke disturbs the ionization process when it enters the chamber, which activates the alarm.

(See our related guide on Photoelectric vs Ionization Smoke Detectors for more details.)

Carbon Monoxide Detection

When fuels containing carbon, such as gas, oil, and wood, are burned insufficiently, a colorless, odorless gas known as carbon monoxide (CO) is created. A separate detection technique is required to detect CO. 

Most carbon monoxide detectors employ electrochemical sensors that detect changes in electrical currents caused by the presence of CO. When CO concentrations reach dangerous levels, the detector activates an alarm to alert occupants.

Sensitivity to Particles

Smoke detectors are designed to respond to smoke particles in the air. They are highly sensitive to airborne particles produced by combustion processes during the initial stages of a fire. 

However, they are not optimized to detect gases like carbon monoxide. CO detectors, on the other hand, are engineered to sense low concentrations of CO gas, making them efficient in alerting occupants to this silent threat.

How To Detect Carbon Monoxide?

Detecting carbon monoxide (CO) is essential to safeguarding the well-being of occupants in residential and commercial spaces. Here are some effective methods for detecting carbon monoxide:

Carbon Monoxide Detectors

The most common and reliable way to detect carbon monoxide is by using carbon monoxide detectors. These devices are specifically designed to sense CO gas in the air and sound an alarm when dangerous levels are detected. 

Symptom Recognition

Even though it’s not a formal method of detection, being familiar with the signs of carbon monoxide poisoning can be crucial in spotting a possible problem. 

Symptoms include headaches, dizziness, weakness, nausea, confusion, and shortness of breath.

CO Test Strips

CO test strips are a simple and inexpensive method for testing the presence of carbon monoxide. These strips change color when exposed to CO, indicating its presence. 

However, they are not as sensitive as electronic CO detectors and should be used as a supplement rather than a primary detection method.

Differences Between Smoke And Carbon Detectors

The following table summarizes the key differences between smoke detectors and carbon monoxide detectors.

FeatureSmoke DetectorsCarbon Monoxide Detectors
Detection PurposeDetect smoke particles indicating fireDetect carbon monoxide gas, a colorless, odorless, and toxic gas
Detection MechanismPhotoelectric or ionization technologyElectrochemical sensors or other technologies
Response to FireTrigger alarm when smoke particles are detectedNo response to fire, focused solely on CO detection
Response to CONo response to carbon monoxide gasTrigger alarm when dangerous CO levels are detected
SensitivityHighly sensitive to smoke particlesSensitive to low concentrations of CO gas
Protection CoverageProtect against fire-related risksProtect against carbon monoxide poisoning
MaintenanceRegular cleaning to prevent false alarmsRegular testing to ensure proper functioning
Symptom RecognitionNo capability to recognize symptomsNo capability to recognize symptoms
Colorless and Odorless DetectionCannot detect colorless and odorless CO gasSpecially designed to detect colorless and odorless CO gas

Can I Interconnect Smoke Detectors And Carbon Monoxide Detectors?

Yes, you can interconnect smoke detectors and carbon monoxide detectors. Many modern models of smoke detectors and carbon monoxide detectors come with the capability to be interconnected. 

This allows them to communicate with each other through wired or wireless connections. When one detector detects smoke or carbon monoxide, it will trigger all interconnected detectors to sound their alarms simultaneously. 

Interconnecting these detectors provides a more comprehensive and effective safety system, ensuring that occupants are promptly alerted to both fire and carbon monoxide threats throughout the entire living space.


The distinct detection mechanisms and sensitivities of smoke detectors render them incapable of sensing colorless and odorless gases like carbon monoxide. 

To ensure comprehensive safety in residential and commercial spaces, it is crucial to supplement smoke detectors with dedicated carbon monoxide detectors. 

By combining these specialized devices, occupants can enjoy a more robust and vigilant protection system, safeguarding against both fire-related risks and the hidden danger of carbon monoxide poisoning.