Around here 80 degrees normally is accompanied with 10% humidity. If you have the air conditioning going and it's 78 or below, the chins will do alright...as long as they are acclimated to it. Of course, I live in Arizona and most people have air conditioning and have extremely low humidity.
In the summer I usually keep it around 75° in the chin rooms. With a lot of air flow 80 degrees wouldn't be that bad...but like I said before WITH LOW LOW humidity.
At the low end you probably don't want the chins getting below maybe 55 degrees. If you are comfortable, normally they are. In the winter keeping them between 60 and 70 is good. Or, a little lower...