My house here in Florida is extremely dusty. I would like to find out
why.

I've asked local tradesmen, but to no avail. Perhaps some of you
might have some ideas.

Here are some details: House 6 years old. Problem 6 years old.
Winter/summer makes no discernable difference. Heat pump, overhead
supplies to each of the rooms, overhead returns from rooms. No dust
collects in supply vents. Some dust, I would say a minimal amount,
collects on return vents. The electrostatic filter in the H/AC never
gets very dirty, and is cleaned twice a year. Yet a fine white dust,
(not the color of any carpeting in the house) settles in all
heated/cooled rooms. The dust rapidly collects on the leading edges of
the blades of fans in those rooms. This dust appears to contain
fiberous material. Bathrooms and kitchen utility room all have tiled
floors, yet have the same problem as bedrooms and living room and dining
room and closets, which are carpeted. Most windows in the house,
especially bathroom windows, are almost never opened. Garage is not
heated or cooled, is not carpeted, and has popcorn ceiling, but has a
minimal dust problem, and dust in garage appears more as dirt (dark, not
white).

Any ideas?

Thanks........ Charlie