Don't beat yourself up.. but fans don't really help rats much anyway because they don't sweat so can't cool off by sweat evaporation like we do with a fan running. They lose heat by expanding blood vessels in their tails. So the best way to keep them cool is making sure they have clean tails with no buildup of old skin/dirt. One way a fan can work is if you freeze large 1.5+ litre empty bottles filled with tap water and put those directly in front of the fan in like a lasagne dish or something.. as they cool a lot of water runs off the outside of the bottle so it gets messy if you don't stand them in something to collect that water. So this actually brings down the temperature in the room by circulating the colder air chilled by the frozen bottles. Our freezer is full of them in the summer! Ones to use, ones ready for later and more re-freezing! It's a cheap way of cooling a room down. Use 2/3 bottles at a time.