First Alert Smoke Detectors Do Not Detect Carbon Monoxide

Standard First Alert smoke detectors are designed to sense smoke from fire, not carbon monoxide gas. If you own a First Alert smoke detector and want protection against carbon monoxide, you need a separate carbon monoxide detector — the two devices use different sensors and cannot replace each other.

First Alert does make combination units that detect both smoke and carbon monoxide in a single device, but these are sold separately from their standard smoke-only models. The label and product name will clearly state "smoke and carbon monoxide" if it does both. A detector labeled only "smoke detector" will not alert you to carbon monoxide.

Key Takeaways

  • First Alert smoke detectors sense smoke particles from fire, not the odorless, colorless gas of carbon monoxide.
  • First Alert makes separate combination detectors that sense both smoke and carbon monoxide, but these are a different product line.
  • A standard First Alert smoke detector will not warn you about carbon monoxide leaks from furnaces, water heaters, or car exhaust.
  • You can identify what your detector does by reading the label or product name on the device itself.

How Smoke Detectors and Carbon Monoxide Detectors Work Differently

Smoke detectors use one of two technologies: ionization or photoelectric sensors. An ionization detector contains a small radioactive source that ionizes air particles; when smoke enters the chamber, it disrupts this ionization and triggers the alarm. A photoelectric detector shines a light beam across a chamber; when smoke scatters the light onto a sensor, the alarm sounds. Both methods detect visible smoke particles.

Carbon monoxide detectors use an entirely different sensor — usually electrochemical or biomimetic — that reacts chemically to carbon monoxide gas itself. These sensors do not respond to smoke. Because carbon monoxide is invisible and odorless, a smoke detector cannot sense it no matter how sensitive it is. The two hazards require two different detection methods.

First Alert Combination Detectors: Smoke and Carbon Monoxide

First Alert manufactures combination units that house both a smoke sensor and a carbon monoxide sensor in one device. These are labeled as "smoke and carbon monoxide detectors" or "dual-sensor detectors" on the packaging and on the unit itself. The product name will include both hazards — for example, "First Alert Smoke and Carbon Monoxide Detector" rather than just "smoke detector."

Combination detectors cost more than smoke-only models but take up only one wall or ceiling space. They run on either batteries or AC power (with battery backup), just like smoke detectors. When either sensor detects a hazard, the alarm sounds and typically announces whether it is detecting smoke or carbon monoxide, so you know which danger to respond to.

How to Check What Your First Alert Detector Does

The easiest way to know whether your First Alert detector senses carbon monoxide is to look at the label on the front or back of the unit. The label will list the hazards it detects. If it says "smoke detector" only, it does not detect carbon monoxide. If it says "smoke and carbon monoxide detector" or lists both hazards, it does both.

You can also check the product manual or the First Alert website by entering your model number. The model number is printed on the back or bottom of the detector. If you cannot find the manual or model number, the safest approach is to assume your detector only senses smoke and install a separate carbon monoxide detector in your home.

Where Carbon Monoxide Comes From and Why You Need Detection

Carbon monoxide is produced by any appliance that burns fuel — furnaces, water heaters, gas stoves, fireplaces, and car engines. Leaks or poor ventilation can allow carbon monoxide to build up indoors. Unlike smoke, you cannot see, smell, or taste it, and it can cause serious illness or death at high concentrations. A smoke detector will not warn you about this hazard.

The U.S. Consumer Product Safety Commission recommends installing at least one carbon monoxide detector on every level of your home, especially near bedrooms. If your First Alert smoke detector does not also detect carbon monoxide, you should install a separate First Alert carbon monoxide detector or a combination unit in those locations.

First Alert Smoke Detector Models and Their Capabilities

First Alert makes dozens of smoke detector models, ranging from basic battery-powered units to hardwired models with backup batteries. None of the smoke-only models detect carbon monoxide. Their most common smoke-only lines include the Basic, Slim, and Onelink models — these sense smoke only.

First Alert's combination detectors are typically labeled with "carbon monoxide" in the product name. Examples include the "First Alert Smoke and Carbon Monoxide Detector" and the "First Alert Hardwired Smoke and Carbon Monoxide Detector." If you are shopping for a new detector and want both protections, look for the word "carbon monoxide" in the product name or description.

Frequently Asked Questions

Can I use a First Alert smoke detector to detect carbon monoxide if I turn up the sensitivity?

No. Smoke detectors and carbon monoxide detectors use completely different sensor technologies. Increasing sensitivity on a smoke detector will not make it detect carbon monoxide — it will only make it more likely to trigger on cooking smoke or dust. You need a separate carbon monoxide sensor.

What should I do if I already have a First Alert smoke detector but no carbon monoxide detector?

Install a separate carbon monoxide detector. You can buy a First Alert carbon monoxide detector or a combination smoke and carbon monoxide detector. Place it on each level of your home, especially near bedrooms. Your smoke detector will continue to work for smoke, and the carbon monoxide detector will cover that hazard.

Do First Alert combination detectors cost much more than smoke-only detectors?

Combination detectors typically cost $20 to $50 more than basic smoke-only models, depending on the type (battery-powered or hardwired). Since you would otherwise buy both detectors separately, a combination unit often saves money and space while providing the same protection.

Will my First Alert smoke detector alarm if there is carbon monoxide in my home?

No. A smoke-only detector will not alarm for carbon monoxide under any circumstances. If carbon monoxide is present and you have only a smoke detector, you will have no warning. This is why a separate carbon monoxide detector is essential.