My home has forced air heat and about half a dozen of our vents are actually on the floor. I don’t think they do that anymore but Victorian construction practices and over a hundred years of “modernization” have left some rather interesting features in our house.
This past spring (or the winter that would not quit here in Minnesota) we noticed that our heat seemed to not be working so well. My head immediately jumped to how to find a furnace repair person and how much that would cost. My wife suggested we try vacuuming out the ducts.
All I can say is OMG, shit is NAA-STY. We filled the vacuum twice in our half-dozen floor vents, found about 20 lbs of kitty litter, two gloves that were never ours, some toys (no human children in our lives), and an empty cigarette box (neither of us smokes). Ew.
A bit of internet research has shown that apparently you’re supposed to do this on a regular basis, but I had never thought to do it before. So now you know!