FYI,
This is an unfinished attic, without climate control atm.
The roof shingles were recently replaced, but not all of the plywood decking underneath was replaced.
Does the attic (unfinished and with new roof shingles) have enough external air vents? I live in a 50 year old house and got a new roof about 15 years ago. They had to add many roof vents when we did the roof. This was a complete roof tear off. I did not replace the insulation, but we need to. 50 year old insulation is (typically) not very good.
We added air conditioning about 4 years ago, but we are using the existing heating duct work, as we already had central heat. Everything works great.