The metal sheds? I can imagine this being a problem with metal. Maybe introduce some crossflow ventilation. Either cut a vent into each end, or drill a few holes each end to get the air to flow.
I bought this shed a while back, positioned it in a well vented area, on a brick / concrete base, inserted two extra vent into the thing so in total the shed has 5 vent, the shed still condenses, the look good but this lets the shed down very badly Builder.
I often wondered TWR, but had no idea they were that bad. Technically, the answer would be to heavily insulate the shed on the outside, which would mean putting a bigger shed over that ;o(((((
Or insulate inside. Maybe make up a plywood box to fit inside the shed. Make it smaller so you can stuff insulation in the space between the two.
What a game though!
I think I'd just get a simple timber one ;o)
I've contacted Keta several times regards this, sent A4 pics of the tools that have rusted up, after a lot of discussion, A cheque for a £100 in in the post for the cost of my tools, ( The value of the tool were in excess of that) I wish I had bought another wood one, that never ever give trouble.