Yes! Just opened a little bit. Not the whole way.

I got my Kyiv sleeping bag at Decathlon. A cheap synthetic one is ideal for this use-case: you don't care how bulky it is or how much it weighs. And synthetic handles moisture better.

Unfortunately in the long run if you have consistent cold weather mold will be an issue... Homes need enough heat to stay dry. There's no good answer there other than finding some way to get heat.