I have a 20' enclosed aluminum trailer. My trailer has a plywood liner and also a vent which seams to keep down any condensation or sweating...We are snowbirds so I have cars and garages both in Arizona and Washington and the trailer seams to be a great dust free, mouse free area to keep one car....One fall I used the Car hauler to help my son move to Phoenix from Washington, we had the trailer loaded mostly with large book shelves and books, anyway we had to hang back in Leavenworth, Washington so my wife could get treatment, so this took to the middle of winter before we could head on south, so I hung a 150 watt light bulb in the trailer and kept the snow shoveled off the roof, I was a little worried about the books and moisture but their was no problem at all.