Gingerbread Exchange Community

I also made houses in FLorida and humidity is a real killer.  I've used Isomalt and that worked well, as well as making sheets of glass from poured sugar. 
However, for ease, I use crushed hard candy Brachs' (butterscotch (golden) or cinnamon (red)).  Jolly Rancher has beautiful colors, but they melted after the second week.

I bake my gingerbread house sides, cutting out the windows (usually no bigger than 2") so the edges are soft.   Then I place each piece back on cookie sheet with a piece of foil underneath window and fill up the window with crushed candy.  Back into oven for 5 minutes, which melts it into glass.  Be sure to pack enough crushed candy in there or else there will be gaps.  The glass does develop cracks when it cools, but they last and the light from inside the house shines through beautifully.