Why you're seeing soot from furnace and how to fix it
If you've walked past your own air vents and noticed a strange, dark powder moving on the angled slots, you're likely looking at soot from furnace accumulation. It's one of those issues that generally starts small—maybe the little smudge around the wall or a bit of gray dust on the white shelf—but it can quickly turn directly into a messy, frustrating problem in case you don't catch it early. Most of all of us don't spend a lot of time thinking of our heating systems until they stop working, but soot is a pretty clear signal that something beneath the hood isn't running quite best. ...