How to tell if it's a smoke alarm or carbon monoxide?

Author: Mrs. Vickie Feil DVM  |  Last update: Wednesday, June 11, 2025

Here's a simple guide:
  1. Smoke alarms alert you with three beeps in a row.
  2. Carbon monoxide alarms alert you with four beeps.
  3. A single chirp means the battery is low or the detector should be replaced.

How to tell if carbon monoxide is leaking?

What Are Signs of Carbon Monoxide in Your Home?
  1. Yellow or orange flames coming out of your gas appliances instead of the usual blue flame.
  2. Dark and sooty staining on or around gas appliances.
  3. Pilot lights that frequently blow out.
  4. Increased condensation on windows.
  5. Solid fuel fires burn much slower than usual.

Will a carbon monoxide detector keep beeping if there's carbon monoxide?

Beeping from a CO detector should never be ignored as it may indicate the presence of carbon monoxide, a dangerous gas. If you suspect CO exposure or if you cannot determine why the alarm is beeping, ensure the safety of all occupants by evacuating and contacting professionals to assess the situation.

What are two warning signs of carbon monoxide poisoning?

The most common symptoms of CO poisoning are headache, dizziness, weakness, upset stomach, vomiting, chest pain, and confusion. CO symptoms are often described as “flu-like.” If you breathe in a lot of CO, it can make you pass out or kill you.

What if the carbon monoxide alarm goes off but no fire?

False or nuisance alarms are when your smoke detector or CO alarm goes off, but there is no presence of smoke or carbon monoxide in your home. However, if your smoke or carbon monoxide detector sounds indicating an emergency and you are not certain it is a nuisance alarm, evacuate the home and call 9-1-1.

Understanding Smoke and Carbon Monoxide Detectors | Ask This Old House

Will opening a window help with carbon monoxide?

If you experience symptoms that you think could be from CO poisoning: DO GET FRESH AIR IMMEDIATELY. Open doors and windows, turn off combustion appliances and leave the house.

How can I detect carbon monoxide in my home?

It is also a good idea to know the signs of a potential CO problem:
  1. Streaks of soot around fuel-burning appliances, or fallen soot in a fireplace.
  2. Absence of an upward draft in your chimney.
  3. Excess moisture and condensation on windows, walls and cold surfaces.
  4. Rusting on flue pipes or appliance jacks.

How do I use my iPhone to detect carbon monoxide?

Go to the Home app on your iPhone or iPad. , then tap Home Settings. Tap Safety & Security. Tap Sound Recognition, then turn on Smoke & CO Alarm.

Should I be worried if my smoke alarm goes off for no reason?

Sometimes, smoke detectors will keep going off for no reason when they have reached the end of their life span. Fire alarms have a lifespan of about 10 years, after which they will need to be replaced. Smart smoke detectors can help eliminate some of the annoyances related to false alarms.

How to test a carbon monoxide alarm?

How to test your carbon monoxide detectors to ensure they are working properly? To test your carbon monoxide detectors, press and hold the test button on the alarm. The detector will sound 4 beeps, a pause, then 4 beeps for 5-6 seconds. Refer to the user manual for your specific model.

What do 5 chirps mean on a smoke detector?

5 Beeps Every Minute: End of Life. This type of chirp indicates it is time to replace your carbon monoxide alarm.

How can you tell if there is carbon monoxide without a detector?

Signs of carbon monoxide:
  1. Stuffy or stale air.
  2. A pilot light keeps going out.
  3. More condensation than usual on your windows.
  4. Soot build up around a fireplace, chimney, or other fuel-burning equipment.
  5. Fuel-burning equipment has a back-draft (flame flares up when a window or door opens and adds air).

What do carbon monoxide alarms sound like?

Here's a simple guide: Smoke alarms alert you with three beeps in a row. Carbon monoxide alarms alert you with four beeps. A single chirp means the battery is low or the detector should be replaced.

Do smoke alarms go off for carbon monoxide?

Fires can produce carbon monoxide, so a smoke alarm won't always detect this gas. On the other hand, carbon monoxide can be present without any visible smoke or flames, making a smoke alarm insufficient for protection.

Can I test myself for carbon monoxide?

Diagnosing Carbon Monoxide Poisoning. There isn't a self-diagnosis option for carbon monoxide poisoning. Symptoms may include: Headache and nausea.

Can my phone check for carbon monoxide?

Co Checker is a free Android app developed by Meter App, falling under the category of Utilities & Tools. It is a simple and handy tool that helps detect the presence of carbon monoxide in the air.

Should I call 911 if my carbon monoxide alarm goes off?

My carbon monoxide alarm is sounding. What should I do? Call 911 and report what is happening. Immediately leave your residence and wait for the fire department to arrive.

How can you tell if there is carbon monoxide in your house?

Signs of a carbon monoxide leak in your house or home

Sooty or brownish-yellow stains around the leaking appliance. Stale, stuffy, or smelly air, like the smell of something burning or overheating. Soot, smoke, fumes, or back-draft in the house from a chimney, fireplace, or other fuel burning equipment.

Do first alert smoke detectors detect carbon monoxide?

First Alert's Precision Detection Advanced Sensing Technology. Voice & Location Alerts for Danger and Helps Escape Safely. Provides Reliable 2-in-1 Protection Against Both Smoke and Carbon Monoxide.

Can dogs smell carbon monoxide?

Carbon monoxide, commonly known as CO, is an odorless, colorless, and non-irritating gas. No pet can identify the gas because CO lacks any scent whatsoever. Exposure can lead to carbon monoxide poisoning in both humans and pets.

How to tell if your smoke detector is also a carbon monoxide detector?

CO alarms and combination CO alarms are always clearly labeled even though many smoke detectors are not. Another way to verify whether your devices can detect both CO gas and smoke is by pressing their test buttons. Modern, hard-wired units will issue verbal alerts such as “Warning!

Does the fire department charge to check for carbon monoxide?

In most areas, the fire department does not charge to respond to carbon monoxide alarms or to check for the presence of CO in a residence. However, policies can vary depending on the jurisdiction or specific fire department. It's always a good idea to contact your local fire department for specifics on their policies.

What if the carbon monoxide alarm goes off and then stops?

If you have a carbon monoxide detector chirping and then it stops, it's important to take the situation seriously, even if the alarm is no longer sounding. Even if the alarm has stopped, get everyone out of the home to a place with fresh air. Contact 911 or your local fire department to report the incident.

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