Now that furnaces are running across the valley and houses are sealed up against the cold, it’s the right time of year to talk about the one furnace hazard that’s dangerous and completely invisible: carbon monoxide. We don’t bring this up to scare anyone. We bring it up because it’s very preventable, and a few simple things protect your family from it entirely. Here’s what every homeowner should know.
What Is Carbon Monoxide, and Where Does It Come From?
Carbon monoxide, or CO, is a gas produced whenever fuel burns. It’s colorless, odorless, and tasteless, which is exactly what makes it dangerous, because you can’t see it, smell it, or taste it. People sometimes call it the silent killer for that reason.
In a home, it can come from any appliance that burns fuel: your gas furnace, a gas water heater, a gas stove, a fireplace, or a space heater. It also comes from a car left running in an attached garage, and from generators and grills, which is why you never run those indoors or in the garage. When these things are working correctly and venting properly, the CO goes safely outside. The danger comes when something isn’t venting the way it should.
How Could My Furnace Produce Carbon Monoxide?
Your furnace burns fuel to make heat, and in a healthy system the combustion gases, including any carbon monoxide, are kept completely separate from the air you breathe and vented outside. A couple of problems can break that.
The big one is a cracked heat exchanger. That’s the metal wall that separates the burning gases from your home’s air, and when it cracks, that separation is gone. A blocked or disconnected vent pipe can also back exhaust up into the house instead of sending it outdoors. And poor combustion, which often shows up as a yellow or flickering burner flame instead of a clean blue one, can produce more CO than a properly tuned furnace should.
This is the real reason annual furnace maintenance matters, beyond comfort and efficiency. When we service a furnace, checking the heat exchanger and the venting for exactly these problems is part of the job.
What Are the Symptoms of Carbon Monoxide Poisoning?
Because you can’t detect the gas itself, knowing the symptoms matters. CO poisoning often feels like the flu, but without a fever: headache, dizziness, nausea, fatigue, and confusion. A few telltale signs set it apart. Often more than one person in the house feels sick at the same time, pets included, and people tend to feel better after they leave the house and worse when they come back.
It’s especially dangerous while everyone is asleep, which is one more reason the detectors below matter so much. If you ever suspect carbon monoxide, don’t stop to investigate it. Get everyone and every pet outside into fresh air immediately, and call 911 from outside. If anyone is drowsy, confused, or unresponsive, treat it as the emergency it is.
How Do I Protect My Family?
The good news is that prevention is simple and cheap:
- Install carbon monoxide detectors. Put one on every level of your home and near every sleeping area. Test them monthly, change the batteries when you change your smoke detector batteries, and replace the detectors themselves every five to seven years, since the sensors wear out. If you don’t have one near the bedrooms, that’s the most important thing on this whole list.
- Get your furnace inspected every year. A yearly check of the heat exchanger and venting catches the problems that cause CO leaks before they become dangerous.
- Never heat your home with the oven or stove, and never run a generator, grill, or car inside the house or an attached garage.
- Keep your outside vents clear. Snow, ice, leaves, and even bird nests can block the exterior vents your furnace and water heater use, so make sure they stay clear through winter.
The Short Version
Carbon monoxide is invisible and comes from fuel-burning appliances, and a cracked heat exchanger or a blocked vent can let your furnace leak it into your home. Protect your family with working CO detectors on every level and near the bedrooms, and have your furnace checked every year. If a detector goes off, or people feel flu-like and better once they’re outside, get everyone out and call 911. Don’t wait that one out.
If you’d like your heat exchanger and venting checked heading into winter, that’s a core part of every maintenance visit we do, and it’s one of the reasons our Comfort Club members start the heating season with a furnace tune-up. We’re a family-run shop covering Nampa, Caldwell, Meridian, Boise, and Emmett, at 208-455-5158.