My heat bills are about twice what neighbors pay in similar houses.
And, I get ice dams. So it seems there is heat leaking up into the
attic. I have soffit vents and a ridge vent. So I called 3 insulation
contractors. One said the 6" that is in the attic between the 2x4
joists is fine and that adding more won't make a big difference. Two
others wanted to add another 6" of cellulose. Pink stuff is more
expensive and doesn't fill nooks and crannies as well.

My walls have 2" insulation which was standard back in 1970 when the
house was built. I replaced all the windows with double pane vinyl
windows. That was years ago and it did make a difference. I have a
large aluminum frame slider that I cover with film for insulation.

I'm hesitant to spend $1600 on additional insulation if it isn't going
to do anything. Can anyone suggest what is causing the heat loss?
Thanks.