Dean Lerner's Reply:
Over the years, I have learned when teaching yoga class to never ask the question, "How is the temperature?" It invariably begins a debate, causes an unnecessary disturbance, and sometimes creates an impasse. The optimal temperature range will vary according to time of year, climate, and situation. The room climate should be as comfortable and pleasant as possible. In my studio, we keep the temperature between 70 and 72 degrees.
Classroom climate control options—or lack of them—vary with the studio, but ultimately the decision concerning temperature level and air circulation lies with the teacher. The teacher knows the class plan—where the poses are leading, if they are warming or cooling, etc.—and can take all those factors into account.
Often students who complain that the room is too hot are wearing tights or long pants that inhibit natural heat release. If that is the case, call that fact to their attention. Basically, the teacher should consider the overall needs of the class first, and make accommodations, if feasible, for an individual afterward. In the situation you describe, it is your duty as the teacher to control and direct the class, and in this case it is most proper for you to tell the student not to adjust the thermostat. This can be done politely and firmly to avoid conflict.
Certified Advanced Iyengar instructor Dean Lerner is co-director of the Center for Well-being in Lemont, Pennsylvania and teaches workshop across the United States. He is a longtime student of B.K.S. Iyengar and served a four-year term as president of the Iyengar National Association of the United States. Known for his ability to teach yoga with clarity and precision, as well as warmth and humor, Dean has conducted teacher training classes at Feathered Pipe Ranch in Montana and other locations.