It's drier than dry here! We have cool nights and hot days in the summer (and air conditioning) and keep it pretty normal (high 60's low 70's in the winter). I find the Gloxinias easier than the AV to grow. As long as I know whenever they look sad to just cut off the leaves, give them a rest, then water and feed well, they come back and bloom like mad. I keep them in my east window. I'd get some pictures, but they are in the sad looking phase at the moment... hehe
I do water with tap water, its what I have and its pretty hard/Alkaline. I top water my one tiny one sometimes, but there is a gap between the leaves I am careful to use and to keep the water off the leaves.