Well I went around my apartment and discovered the outside brick mortar was dry and loose. The landlord had a fellow come out and refill all that and it stopped all the drafts.
Before he did that I bought the rolls of silver covered thermal bubble wrap and tapped it to the one wall in the winter. Worked great even though I didn’t like the look...better to be warm than pretty! LOL I think the whole roll was like $20 and I had plenty left over.
I used that in my shed along with the foam block insulation. I like how it looks! The entire interior wall surface of the shed is like that. The slightest bit of light inside makes it bright with all the reflectance.