This can kill your chin or at the very least have devastating health consequences leading to an early demise. Nothing over 80 degrees, and watch for when ever then temperature combined with the percentage of relative humidity is 150 or more. Your animals will be comfortable. If you do not have air conditioning, keep you cages in a cool basement or you can freeze plastic bottles full of water to cool the beasts. A 2 litter pop bottle, frozen solid, wrapped in a towel could be enough to keep your chin cool in the heat of the day.
Heat is the most likely killer of pet chinchilla's.
So plan for this if you want to keep your pets happy. Other furnishings for a chins lair will be a large water bottle, a crock type dish or a pellet bin like the ones used for rabbits, a house or hiding tube and a hard chew block. The chew toy is very important as the teeth grow constantly all the life of these animals. Untreated pine, this comes in blocks or logs, or a lava rock chew, meant for these types of rodents. Wooden toys made for large parrots can be used for your pets also.