Some more mundane stuff. Am in the middle of re-insulating our attic. It is partially floored so I'm just leaving the new insulation on top of the finished portion. For the unfinished portion I'm removing the old stuff and came across some old insulation called "rock wool". My first thought was: Does this stuff contain asbestos? In the end I am convinced not.
The previous owners had upgraded the insulation from rock wool to R-19 Owens Corning fiberglass insulation. DOE recommends R-49 but the highest value Home Depot and Lowes carries is R-38. I figure if I put the R-38 down and leave the existing R-19 in place it should be enough.
Unfortunately, it does not appear to made any measurable difference in temperature. Our upstairs tends to be colder in the winter and vice versa in the summer. We either need larger or more vents upstairs I think.