<p>Not necessarily. Many dorms will control when you can and can not run the air conditioner and many times during the winter (especially if you are on a top floor), it can get very warm and the heat will run regardless and there may be no option to turn on the AC. For an instance like this, a fan is necessary though the dorm may be equipped with AC.</p>
<p>Sometimes when the AC is on, it can get FREEZING cold really quick if you leave it on. Therefore, the fan could be useful to keep air circulating and keep it comfortable if having the air on is making it TOO cold in the room during the warm months.</p>