Shipping container for storage - ventilate or insulate?

[CambsBill]

Or both?

Asking for a friend (yes, really) who plans to get hold of a container to store a variety of stuff, including books, but isn't sure whether it's better to instal some form of ventilation or insulation to prevent condensation. I know which way I'm leaning, but anyone out there with actual experience of this who could help?

[Alex Z]

Ventilation, with books inside plastic containers that are easy to stack and will protect them.

[dickymint]

Both - but only insulate the roof as this should allow any condensation to form on the walls and not drip from the ceiling onto 'the books'.

[dhutch]

Yeah, even just cheap/used carpet on the ceiling well help reduce condensation.

I would also look to put everything valuable/sensitive in plastic boxes with a well fitting lid.