Carbon Monoxide

(C) 2009 Jim Morrison

Any flame can produce carbon monoxide (CO). Most people associate CO poisoning with their heating system or their car, but plenty of folks have been poisoned by their fireplaces and wood stoves too. If you are concerned about CO poisoning in your home, there are just a few things you need to know:

How it is produced:

CO is a product of incomplete combustion. If a flame is supplied with just the right mix of fuel and oxygen, it will burn completely (cleanly) and will not create CO. Gas burning heating systems and water heaters are the most common sources of CO in my experience because there is a common misconception that since gas burns cleaner (to the eye) than oil, it never needs servicing. This myth is probably the reason I find CO problems with more gas fired heating systems than not. Every combustion appliance in a home needs regular maintenance, period. For most of us, this means hiring a professional. Gas and oil fired heating equipment MUST be thoroughly cleaned and serviced by a licensed professional annually. If you have a fireplace or wood burning stove and you use them once a week or so during the heating season, the flues should be cleaned and inspected by a certified chimney sweep every year. If you use a wood stove, don’t use it unless you have a permit from your town.

Another issue I run into more and more often lately is: finished basements. Real estate values have about doubled in the past 5-7 years, which means every square inch we can squeeze out of our property is worth a lot of dough. A lot of homeowners are having their basements finished these days so they can capitalize on the increased value. The contractors who finish off basements don’t always realize the effect they have on other systems in the house. Finishing off the basement often deprives the heating system and water heater of sufficient air for combustion and dilution. In extreme cases, this can result in CO production and sometimes it can fill the house with enough CO (and aldehydes, carbon dioxide, etc.) to be lethal. A heating system for an average sized house needs 5000 cubic feet of room (height x width x length of room) for safe operation. You can easily measure it yourself and if you have less than that, call a heating contractor.

How to avoid it:

Having your heating equipment serviced every year will help you avoid CO problems, but not eliminate them. Installing one or more UL listed CO detectors throughout the house is the best protection. CO is undetectable by the human senses and can cause significant health problems at concentrations of just 9 parts per million (ppm) over eight hours. It can effect the elderly, the ill, and the very young at even lower concentrations. The bottom line is: CO is not a naturally occurring compound and should not be found anywhere in your home. Even 1 ppm is too much because if you have a little, you can get a lot. The latest figures available from the US Consumer Product Safety Council indicate 10,200 people have to go to the Emergency Room each year because of non-fire related CO injuries. Of those, 534 people die. With regular maintenance and the installation of CO detectors, CO injuries and deaths can be virtually eliminated.

Here’s something else to consider: Many people today burn scented candles in their homes. If the rim of the glass around the candle is sooty and you find soot on your ceilings and especially your windows, these candles are not burning cleanly and could be producing CO in your home (as well as other noxious gases). For a lot more information about indoor air quality, visit this excellent website. There is a lot of good info there to keep your home and office air healthier.

Jim Morrison
Morrison Home Inspections
978.851.6315
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