What Are the Signs of a Carbon Monoxide Leak?

Carbon monoxide (CO) is known as the “silent killer” for a reason. It’s clear, scentless and difficult to recognize without the right tools. If it accumulates in your home, it can quickly become 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 use carbon monoxide detectors. These alarms are your first line of defense, alerting you to the presence of CO gas before the situation reaches dangerous levels. But aside from a detector going off, how can you tell if there’s a carbon monoxide leak in your home? These are 10 warning signs to be aware of.

1. Condensation on Windows Nearby Appliances

If you spot heavy condensation on your windows, particularly near a gas-powered device like a gas fireplace, this could mean that there’s an issue with ventilation. While condensation alone isn’t always CO-related, this still should be checked out.

2. Yellow or Brown Stains

Fuel-powered appliances should always have clean, clear exhaust. If you find brownish-yellow or sooty stains around a furnace, fireplace or water heater, combustion isn’t happening as it should. This may point to a carbon monoxide leak.

3. Exhaust Fumes Appear Indoors

If you start to smell exhaust fumes indoors, you are in danger of carbon monoxide symptoms. Fuel-burning appliances like cars, charcoal grills and generators should always be used safely outside the home to prevent an accumulation of exhaust fumes indoors.

4. Soot in or Around the Fireplace

Your chimney should channel smoke and other gases through the chimney. Seeing soot buildup around your fireplace is cause for concern, especially if there’s more than usual. A clogged chimney could be why carbon monoxide is coming back into your home.

5. Weaker or No Draft from Your Chimney

On the topic of chimneys, a properly working one needs the solid updrafts to fully pull out smoke and other fumes. If you notice a weak draft or even no draft at all, the chimney could be clogged, sending carbon monoxide back into your home.

6. Yellowish or Weak Flames

Most gas-burning appliances should have a clear blue flame. Whenever the flame is weaker and yellow (and it isn’t a decorative gas fireplace), it can mean the gas has combustion issues and may be producing carbon monoxide.

7. Solid Fuel Fires Burning Slowly

If your wood or coal stove starts taking longer to burn or has trouble staying lit, it could have a ventilation issue, heightening the possibility 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 might 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 together with any of the warning signs listed above, get fresh air immediately and call 911.

Prevention and Safety Tips

It’s always better to prevent issues than respond to them, especially in the case of CO gas exposure. For the most basic safety, check that there are carbon monoxide detectors in all the right places. Building codes require them in hallways near all bedrooms, on each level of your home and in rooms with fuel-burning appliances. For extra safety, it’s wise to install interconnected detectors so that when one detects CO, all of them will raise the alarm. Perform monthly testing and swap them out when necessary, about every five to seven years.

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