Wanted to give the results of my efforts this past weekend. Short version...huge success balancing out the air flow/temps in the camper...and much increased airflow to the bunkhouse where it was needed most.
I replaced all of the fixed-louvered vents with adjustable-louvered vents. Almost all of the holes that were drilled into the ceiling and through the vent ducts were taped up very sloppily. For each vent, I examined the seals and either removed the old tape/foil and re-sealed it...or just taped the areas that had gaps. I closed off 90% of the air in the two bathrooms and the master bedroom to force more air into the rest of the coach and especially the bunkhouse. Those yielded pretty good results. I also took down the ducted A/C's return cover and examined the inside. Low and behold -- a hole about the size of a silver half-dollar between the plenum and one of the ducts that was taped improperly. I taped up that hole -- which was right below the blower cage -- buttoned it all back up -- and checked out the airflow to the vents. All of them increased with that repair. The real test was yesterday. It was full sun and 92 degrees at my house. I ran just the main A/C unit (left our bedroom unit off), set it to 73, and left for a few hours. Came back around 2:00 and the living room was 73 degrees. When I opened the bunkhouse and took the temperature there, it was also 73 degrees. SUCCESS!! Well worth the few hours of research and few hours of repair time. Plus I have balanced the air flow and now nobody will freeze their arse off in the bathroom while taking a shower. The bathrooms were the coldest since they had a dedicated vent in each small space. With them mostly closed off they now stay cool without getting overly cold. Best of all is that my girls will sleep in cool comfortable A/C at night and have the same temps in the bunkhouse as the rest of the camper. Not sure what percentage of A/C was going into the attic space, but I like that I have taken all of that back and put it into the living space where it belongs.
