Just realized wool insulation fixed my van's damp wall issue

I used to think spray foam was the only way to insulate a van properly. It looked solid and sealed everything up tight. After a few months living in it, I woke up to wet walls and a musty smell every morning. A guy at a campsite told me to try wool insulation, so I pulled out some foam and put wool in one wall. The moisture problem went away almost instantly. Wool lets the van breathe, so no more condensation buildup. Putting it in was no big deal, just cut the batts to size and press them in. Now my van feels drier and stays at a nicer temperature all day long.