I HAD A SEWING ROOM IN THE BASEMENT (with dehumidfier) Never had any problems with mildew. Did keep everything off the floor (on shelving) One nice thing the ironing board could be left set up and I could walk away from my sewing w/o having to pick it up. We moved to the shores of Lake Michigan ---no basement. Sew in a converted garage. Can still shut the door. Mess out of sight.

I sew in the basement year round. I set my machine under the heat/air vent so I'm warm in the winer and cool in the summer. I also run a dehumidifier all the time. That way it doesnt make my fabric smell or my machine sweat.