What Are the Warning Signs of a Carbon Monoxide Leak?

Carbon monoxide (CO) is known as the “silent killer” for a reason. It’s invisible, scentless and hard to detect without the right tools. If it builds up in your home, it can swiftly pose a serious threat for you and your family. So, how do you stay safe against something you can’t really notice naturally?

The key is to have carbon monoxide detectors. These safety devices are the initial line of defense, alerting you to the presence of CO gas before the situation becomes life-threatening. But besides a detector going off, how can you know if there’s a carbon monoxide leak in your home? Here are 10 warning signs to be aware of.

1. Condensation on Windows Nearby Appliances

If you notice lots of condensation on your windows, namely near a combustion-based system like a gas fireplace, this could mean that there’s an issue with ventilation. While condensation alone isn’t always CO-related, this clue should be checked out.

2. Brown, Sooty Stains

Fuel-powered appliances should always have clean, clear exhaust. If you see brownish-yellow or sooty stains around a heating system, fireplace or boiler, there may be combustion issues. This can be a sign of a carbon monoxide issue.

3. Exhaust Fumes Indoors

If you start to smell or see exhaust fumes indoors, you are in danger of carbon monoxide leaks. Devices that burn fuel like cars, charcoal grills and generators should exclusively be operated outside to reduce the risk of exhaust fumes indoors.

4. Soot in or Around the Fireplace

Your fireplace should vent smoke and other gases up through and out the chimney. Noticing more soot or grime is a red flag, especially if there’s more than usual. An obstructed flue in the chimney could be why carbon monoxide is leaking back indoors.

5. Weaker or No Draft in Your Chimney

Speaking of chimneys, a properly working one needs the solid updrafts to fully remove smoke and other fumes. If you notice reduced ventilation or even no draft at all, your chimney might be clogged, pushing carbon monoxide right back indoors.

6. Yellow or Weak Flames

Gas-powered appliances should have a clear blue flame. If the flame is yellow or flickering (and you don’t have a decorative gas fireplace), it can mean the gas isn’t burning properly and might be releasing carbon monoxide.

7. Solid Fuel Fires Burning Slowly

When your wood or coal stove starts struggling to burn all the way through or has trouble staying lit, it could have a problem with airflow, heightening the possibility of CO buildup.

Symptoms of CO Poisoning

If you fail to notice the first red flags of a carbon monoxide leak in time, the next one may soon come from your health. Symptoms of CO poisoning include:

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

If you or anyone in your household experiences these symptoms, especially combined with any of the previously mentioned clues, get fresh air immediately and call 911.

Prevention and Safety Tips

Prevention is always better than a cure, especially when it comes to CO gas exposure. For the most basic safety, check that there are carbon monoxide detectors in appropriate places. Building codes require them outside every bedroom, on each level of the house and in rooms with fuel-burning appliances. For an additional safety measure, it’s best to use interconnected detectors so that as soon as one goes off, all of them will alarm you as well. Perform monthly testing and change them when required, approximately every five to seven years.

In addition to using carbon monoxide detectors, follow these safety tips: