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Duct Cleaning: Don't Bother
The duct cleaning people seem to be coming out of the woodwork lately. I've had at least twenty calls in the last three weeks to have my air ducts cleaned for a “special price”. In fact, the cleaners recommend you clean your ducts annually, which would be great if it actually accomplished something.
Don't be misled into having your ducts cleaned. According to the CMHC, the only time duct cleaning has any benefit is when you've recently completed a major renovation and a large amount of dust and debris has fallen into your registers. (By the way, cover your registers before you start your renovation!)
Why does CMHC make such a strong statement against duct cleaning? To see why, just follow the breeze.
Let's start with some dust-laden air floating in a room of your house. The dusty air enters your ducts through the intake grilles (usually one per floor). Some of the dust actually accumulates right on these grilles—so vacuum them, for free.
The dust that successfully enters your duct system now begins to make its way toward your furnace via the return ducts. Some of the dust will be heavy enough to settle in the return ducts. You don't need to worry about this dust, because you'll never see it again.
You can clean it out of your ducts if you like, but it won't make a difference to your air quality, because it's not airborne. (And don't fall for the claim that settled dust will restrict your airflow—it would take an absurd amount of accumulation for that to happen.)
The remainder of the dust will proceed to your furnace filter. Depending on the type of filter, it will trap varying amounts of dust (that's why you need to clean or replace it every three months). Obviously, dust trapped by your filter is also not harming your air quality, and isn't helped by duct cleaning.
Finally, the smallest and lightest dust will flow right back out of your duct system and into the air. Now, this is one type of dust that does affect your air quality. Too bad it's not in your ducts, and can't be reached by duct cleaning!
We've come full circle, and we've yet to find a purpose for duct cleaning.
My advice? Instead of worrying about duct cleaning, just use a high quality furnace filter, and clean or exchange it regularly.
Want to know more about maintaining your home? Just ask me, I'll be happy to help.