Originally Posted by TromboneAl
BTW, the duct cleaning was a total waste of money, except for the fact that it enabled me to find the hole that the mice used.
The amount of stuff that was flushed out of the ducts was about a cup's worth of debris. Either all the stuff that was in there was near the registers, and had been vacuumed up by me, or the system wasn't effective at removing debris.
A while back, I cut a hole in one of our ducts to add a vent in the basement, and I was surprised how clean it was. Now, If I reach into the ducts near a floor vent in the house, there will be some dust and dirt collected at the bend where the duct rises up, so some dirt falls out of the air stream at that point, which makes sense.
But that got me thinking - if it's clean it does not need cleaning (duh), and if there is some dirt there, well, the dirt is 'there' it isn't getting blown all through the house (otherwise it wouldn't be 'there'). And if that much dust was getting blown around, my filters would be clogging in short order.
Maybe running w/o a filter is a reason to get the ducts cleaned, but it seems unnecessary for most cases.