My old 31 foot Winnebago had two air conditioners but only 30 amp service. Never had problems keeping cool down at the coast(Corpus Christi) in 80-100 degree weather with very high humidity. Ours was not ducted so in the day time I ran the bedroom a/c and pointed the duct to the front, at night ran the front a/c and pointed the duct to the bedroom. It did not cool the rv to 60 degrees, but kept the temp around 76-78 degrees during the day and a little cooler at night. We keep our home at 77, our old bones don't like the cold anymore.