Thanks guys. The way mine is set up, the shutters & exhaust fan are triggered at 75 degreees, and the swamp cooler at 85.
Yes, I have put higher light plants in the front (it's really only part of the front wall that gets late-afternoon, near-horizontal rays that burn), but I think I still may have to add a little shade there as summer comes.

I haven't grown vandas in the past, but am looking forward to trying them now!