Probably lots of factors . What were the surfaces last wiped with, were the windows left ajar or not, different level of shade, different position and wind exposure, have they blocked some air vents, are the vents of differing design and positions etc, etc. Trying to tie it down is very difficult, so many variables.

I've always used a winter cover over all my vans and a small oil radiator switched on low and never experienced any damp or mold.

I pulled off the winter cover 1st weekend in March and all was nice and dry. Water system tested, no leaks and working.
I'll be giving the van it's 1st test run this weekend and booked in with Sandy to come to the house to do the yearly service on Wednesday 26th March.
Then its off for the 1st weekend away of 2014 at Yellowcraigs from Friday 28th which is their opening weekend of the year.
I always like to do 1st and last weekends of the year at Yellowcraigs.

David

Got me worried now. I hope to get the cover off early next week, too busy this weekend away in a s*a*i* van on a hash function and celebration at a commercial site just down the road near Ferndown.

Stalin?

Static lol