All you need fans to do is curculate air. If you have two or more rows of cages, arrange the fans at floor level so that they are set to blow in opposite directions (one blowing east the other west, etc.). That will ensure proper circulation throughout the area. Also, remember to pull the grates off the front and back of the fans and clean the grates, blades, and most importantly the motor of any dust, hair, dander, and debris a couple of times per month. Vacuuming them is a sensible step, as well. It sounds like alot of work, but it's really not, and it will make all the difference in the world in maximizing how much airflow the fans will be able to generate while preventing a very real fire hazard and extending the life of the fans. A properly cleaned fan running on medium speed will generate more airflow than a fan which has not been cleaned properly and is running on its highest setting.