I am also looking for something to put over the thin wood panels on a folding door. Yesterday, I put horizontal strips of plexi over the windows with 1/8th" offset hold-downs. There was an immediate difference in temperature and this morning there is no ice on the windows. Yesterday morning the ice was about 1/8th " thick and when it melted it soaked the door. I'm facing south with the doors and am very happy so far with the results. I added another row of windows above the existing ones, since the doors face south and the cost of the plexi to cover 24 windows on two doors was $126.00 with hardware.