I use the high-low-auto fan button often. When in the bedroom I set the bedroom air conditioner to low fan speed to cut down on the noise so the TV can be heard. When in the living room I set the living room air conditioner fan speed to low so that TV can be heard. Otherwise, all three air conditioners are usually set to auto. Note: When I purchased the coach, as I recall, I was told in order to speed up or skip the air conditioners' start up delay, then turn on the air conditioners and set their fan buttons to either low or high. But, if all the fan button does is set fan speed, then I suspect the start up delay cannot be circumvented.