How hot is too hot?

Der Speigel asks the question
and comes up with, um, environmentally-unorthodox answers.

For me, too hot is a humid 82, or a really, really dry 95. I turn the A/C on when the house -- full of air that isn't really moving -- gets above 75.

I wouldn't get dogmatic about that, but I will get grumpy if I sweat too much when I'm sleeping.