Are you feeding them with an orchid specific fertilizer and, if so, how often...? That's the single most important care one can give an orchid, especially indoors.

The ice and fridge works wonders for some folks, while total disaster for others.

I've never grown an orchid indoors, though your southern exposure sounds about right... and if the plants are Phalaenopsis type orchids, they do not need direct sunlight and do better in filtered light. Most growers who grow their Phals indoors, cut the spike down to the base.