Dash air didn't come close to cooling the entire unit on my former 34' gasser, doesn't do it on my current 39' pusher. I use the generator and central air on both. My wife is very sensitive to heat, and for us, it's a matter of life or death (mine), so I don't worry about the negligible additional cost. Actually, I've never noticed a great difference, and it gives the generator a good workout.
GM