The attic is a mess. As it is not a priority item I have ignored it even though I occasionally can hear it calling out to me: Clean me! Cleeeeeeeeeeeeen me! Cruelly, I have ignored these plaintive pleas.
I do however have a plan:
Heat/cool the attic, and use it as storage.
Access is currently by a dropdown stair, and it is awkward and dangerous at the top. Replace this with good stationary stair in better location.
Relocate heating/cooling unit to floor below.
Rethink insulation. There is currently a lot of insulation in the floor. It seems that new thinking on the subject says that this whole approach is wrong. Rather, I need to have the underside of the roof sprayed with closed-cell foam. This will keep the attic from getting super hot. Then, from what I gather, I should remove the floor insulation. The point is that if it is 95 degrees outside, and 150 degrees in the attic, then the AC on the fourth floor is working extra hard to compensate for the super-hot attic radiating all that heat. Well, that does make sense. In short, the idea is to prevent the attic from getting super hot. NOTE: I am just learning about all this. Please feel free to comment!
Replace all flexible ducting with rigid. Relocate all ducting to perimeter of attic rather than snaking cross the floor.
Install floor throughout!
When all of the above is completed, clean, baby, clean!