I have a high tolerance for heat and get cold easily so the way I judge it is if I can walk around in shorts and shirt bc i want to, not bc it's warm inside then they are good but if I feel I have to wear shorts bc it's warm then I turn the fan on for them. Right now mine are more active at night when the fan is off but I have to turn the fan on around noon bc it gets too warm in my opinion. I give them a big hammock and big pouch so they candivide themselves up into two sleep groups but they all seem to like piling into one....and it makes for some sweaty babies at the bottom lol.
Resa