Yesterday I enlisted the help of my nephew and we tackled the insulation. You can see the 2x4 walkway down the center isle.
We discovered a opening that lead to a small room. You can see the opening. The previous insulators totally skipped over it. No wonder that room was super cold in the winter.
I took a temperature reading before and after. It was as much as 4 degrees difference between the rooms.
The rooms now have all even temperatures and the furnace is noticeable not cycling as much. I spent $300 on the insulation, rented the machine for free and woke up warm this morning! I wish we had done this years earlier.