What Are the Signs of a Carbon Monoxide Leak?

Carbon monoxide (CO) is referred to as the “silent killer” for a reason. It’s clear, scentless and hard to notice without the right tools. If it accumulates in your home, it can quickly become a danger for you and your family. So, how do you protect yourself against something you can’t see, smell or taste?

The key is to have carbon monoxide detectors. These small alarm systems are your initial line of defense, warning you about the presence of CO gas before the situation gets dangerous. But besides a detector going off, how can you recognize if there’s a carbon monoxide leak in your home? Below are 10 warning signs to be aware of.

1. Condensation on Windows Nearby Appliances

If you see heavy condensation on your windows, especially near a fuel-burning appliance like a gas fireplace, this could mean that there’s an issue with ventilation. While condensation alone isn’t always CO-related, this still deserves a closer look.

2. Yellow or Brown Stains

Combustion-based appliances should have unobstructed ventilation. If you notice brownish-yellow or sooty stains around a heater or gas fireplace, it could mean something’s wrong with the combustion process. This can signal a carbon monoxide risk.

3. Exhaust Fumes Indoors

If you can smell exhaust fumes inside the house, you are at risk of carbon monoxide exposure. Fuel-burning appliances like cars, charcoal grills and generators should only be used outdoors to avoid the buildup of exhaust fumes indoors.

4. Soot in or Around the Fireplace

Your chimney should channel smoke and other gases up through and out the chimney. Finding soot inside or around the fireplace is a red flag, especially if there’s more than usual. A clogged chimney could be why carbon monoxide is coming back indoors.

5. Weaker or No Draft from Your Chimney

Staying on the topic of chimneys, a properly working one needs the strong airflow to fully pull out smoke and other fumes. If you notice a weak draft or even no draft at all, your chimney may be obstructed, forcing carbon monoxide right back indoors.

6. Yellow or Weak Flames

Most gas-burning appliances should produce a distinct blue flame. Whenever the flame is weak and yellow (and it isn’t a decorative gas fireplace), it means the gas isn’t burning properly and might be releasing carbon monoxide.

7. Solid Fuel Fires Burning Slowly

In situations where your wood or coal stove starts taking longer to burn or has trouble even staying on, it could be dealing with a problem with airflow, increasing the risk of CO buildup.

Symptoms of CO Poisoning

If you fail to notice the initial warning signs of a carbon monoxide leak in time, the next one could come from your body. Symptoms of CO poisoning may involve:

Flu-like symptoms
Headaches
Dizziness
Nausea or vomiting
Shortness of breath
Confusion
And fatigue

If you or anyone in your household suddenly feels sick, especially combined with any of the previously mentioned clues, leave the house right away for fresh air before you dial 911.

Preventing CO Leaks and Top Safety Tips

Prevention is always better than a cure, especially in the case of carbon monoxide. First, ensure you’ve installed carbon monoxide detectors in appropriate places. Building codes require them outside every bedroom, on each floor of the house and in rooms with gas-powered equipment. For added security, it’s smart to set up interconnected detectors so that when one goes off, all of them will sound. Check your alarms monthly and swap them out when necessary, generally every five to seven years.

Along with having enough carbon monoxide detectors, keep these safety precautions in mind: