11 Sources That Give Off Carbon Monoxide In Your Home


Carbon monoxide, the silent killer. It’s colorless, odorless, and mere minutes of exposure at high levels can be lethal. It makes sense to take inventory of potential carbon monoxide risks around your home.

But what exactly can give off carbon monoxide in your home? Anything that burns gas, wood, oil, or charcoal can give off carbon monoxide. This includes stoves, clothes dryers, furnaces, heaters, water boilers, generators, lawnmowers, grills, tobacco and some paint remover products, and even idling cars in the garage.

Let’s take a look into more detail about each of these and discuss some actionable tips to help you minimize the risk.


Gas Appliances

Gas Stoves

Gas stoves give off carbon monoxide, along with other dangerous chemicals. Newer gas stoves have had major improvements and give off far less carbon monoxide than older gas stoves, so it might be time to buy a new one if in doubt.

Don’t forget that a proper range hood is equally as important as the gas stove. Buy one that has a fast, powerful air flow. Allow it to ventilate to the outside rather than just to recirculate the same pollutant air coming from the cooking.

TIP: Is your gas stove burning a blue flame? If yes, it works properly and has enough oxygen to form a clean methane fire. If the color is yellow or orange, it’s an indicator that there isn’t enough oxygen available to form a proper flame. This is how carbon monoxide forms. Check your air shutter before it’s too late.


Gas Clothes Dryers

If your clothes dryer runs on gas, chances are that it releases carbon monoxide. Although, the level we’re talking about here is much lower compared to some other things in your home that are turned on constantly.

As long as the gas dryer is properly serviced, any level of carbon monoxide it emite should be negligible. But if the dryer vent is clogged or the gas line has a leak, then it means that carbon monoxide staying in the home instead of being vented to the outside.

If you haven’t checked this in years, it’s time to do so now.


Gas Hot Water Boilers

Similar to a clothes dryer, a gas boiler also steers any carbon monoxide to the outside with a flue. And similarly, a blockage here can also create carbon monoxide build-up.

Look for stains around the boiler, as well as soot or debris build-up. Is the pilot light on consistently, or is it too weak to stay on (a sign that there isn’t enough oxygen around)? Is it blue or yellow/orange?

Oil or propane hot water boilers also give off carbon monoxide.


Kerosene Gas Heaters

Kerosene gas heaters have to be monitored all the time (hopefully, yours isn’t on while you’re sleeping). Besides the obvious risk of fire, they can quickly release toxic fumes of carbon monoxide, carbon dioxide, nitrogen dioxide, and sulfur dioxide if the room isn’t well ventilated or the heater if faulty.

Propane heaters also give off carbon monoxide.


Gas Furnaces

If there is a leak with the heat exchanger, flue, or some other problem constricting air flow, carbon monoxide could stay in your home instead of being ventilated to the exterior.

At best, it could simply mean that you forgot to change the air filter and the system is clogged. At worst, it may mean having to replace the heat exchanger entirely, which could be quite pricey.


Anything That Burns Wood, Oil or Charcoal

Carbon monoxide forms during incomplete combustion. In other words, when there is not enough oxygen available to form carbon dioxide.

Incomplete combustion doesn’t only happen when natural gas is burned. Carbon monoxide can also form when wood, oil or charcoal are burned.

So any fireplace or chimney needs to be checked regularly. While carbon monoxide is minimal and clears out after each use of a fireplace, it can stay inside the home if soot and creosote are allowed to build up and the chimney is obstructed and isn’t ventilated properly.


Hazards In Your Garage

Pay close attention to your garage. There may be some hazards there you’re not even aware of.


Vehicle Exhaust Fumes

Leaving a vehicle exhaust to run for just 10 minutes in a closed garage is enough for carbon monoxide to build up to lethal levels.

So if you have an attached garage, never leave your car to run inside idly – even if the garage door is raised.

If it’s winter and your car needs to warm up, back it out of the garage and let it warm up in the driveway instead. And while you’re add it, install a carbon monoxide monitor in your garage if there isn’t one yet.

Portable Generators

Look around your garage and notice anything else that may emit carbon monoxide. A portable generator in the garage is far more dangerous than the vehicle itself. The engine of the generator, in fact, emits 450 times as much carbon monoxide as a single car does.

So it’s as if you had a whole parking lot of cars in your garage, all emitting carbon monoxide when left on.


Charcoal Grills and Lawnmowers

Hopefully, you know better than to light up a charcoal grill or to turn on a lawnmower inside a garage. In case you need a reminder to use those things outdoors only, just know that they too create carbon monoxide.


Products that Produce Carbon Monoxide

Carbon monoxide isn’t only limited to permanent structures and appliances in your home. There are some products that can also create carbon monoxide. Those will be a lot easier to remove from your home.



Tobacco burning creates carbon monoxide. Limit the use of cigarettes in your home. Smoke outside or create a designated smoking area that’s SEPARATE from the common ventilation system.


Paint Removers

Paint removers that contain methylene chloride form carbon monoxide. Dispose of them if they happen to be sitting on a shelf in your garage or basement.


Condensation On Windows

Usually, when people see condensation on windows, they typically think of mold. But did you know this could be a sign of carbon monoxide too?

All those appliances I listed – fireplaces, water boilers, clothes dryers, heaters – have one thing in common:

They all have to vent to the exterior.

So if the water from cooking and showering isn’t escaping your home through those vents, it means that likely any other pollutants aren’t either. Check to find the source of those foggy windows. Chances are, unless you just have old, poor quality windows, there’s a bigger problem looming than just carbon monoxide.


That’s it, those are the 11 most common sources of carbon monoxide in your home. Take a weekend to check your appliances for leaks and clogs, and don’t allow your car to run idly in the garage.

And as always, buy a carbon monoxide detector on each level of your home to be sure.


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