I've had mildew, but it was on my last trailer, not the Escape. 1 year out of 8, it was no fun scrubbing the complete interior, it was on everything. I had left the vent open and the kitchen window cracked figuring airflow was a good thing, the trailer had a Tyvek cover on it. The trailer was about the size of the 21, except better insulated. I do recall entering the trailer one day and finding condensation on all the hard surfaces, don't remember the weather conditions.