Originally Posted by funfinder5
I don't understand how so many run just the dash air and keep your coach passengers comfortable. Motorhome is 32ft long ~8ft wide and +6ft high inside. Even minivans and SUVs have dual air for rear passengers. Shoot our minivan that's only 16ft long with a lot less cubic feet to cool, I can't cool the rear passengers with just the dash air on.
I had my doubts too but I figured I would try it and make adjustments (run the generator and roof air) if needed. The 4 hour trip in mid-day went fine. My son sat at his bunk/bench and my wife sat at the living area couch (the 3171 model). No one ever complained. We made one stop for shopping and when I walked into the coach from the drivers seat I was surprised how cool it was in the coach area just from the dash air. Now when I returned from the shopping 25 minutes later, the coach did heat up pretty good (I didn't run the roof air while we were gone). It took about 20 minutes for the coach area to cool back down - still without running the roof air.
I did do some experimenting with roof vents thinking opening the back one would allow the dash air to move through the coach. I don't think open or closed made much of a difference. I didn't want to operate the front vent with or without the vent fan running because I felt it would pull the cool air out rather than letting it reach the back of the coach.
All I can say is experiment a little. You won't get it down to 70 degrees in the coach when it's 90 degrees outside but it will be comfortable.