We just purchase the Big country3650. The first time we used it the AC vibrated and was so loud we could not hear the TV and sitting on the couch was numbing. We took it back and they replaced the AC unit. Now the new AC will not cool the camper. It was 90 out and the camper inside was 80. At night it did cool a little. The air coming out of the AC is cool, but not cold enough to cool the camper. I covered all windows and no difference. It is a 15,000 BTU is that unit big enough? If we buy a second AC will that help cool the main room? I would hate to be in it when it gets to 100.