We first tried a passive vent in the roof which was adequate in Newfoundland last year (1 month), other than a couple of evenings that were still 30C at 6pm. We usually travel in southern Ontario or the Maritimes tho and it gets too hot/humid with me, hubby and our aussiedoodle in the teardrop so this spring before our vacation, hubby installed the Max Fan. I'm please to say it has been an excellent addition and really helps keep things cool in the teardrop when it's hot and humid. It has been storm tested on the highway during it's maiden trip we had a massive rain storm and we had absolutely no leaks. This fan has 4 speeds and thus far we only had to use it on it's lowest setting although I expect in the middle of summer we'll need more airflow. I am a very light sleeper and find that the fan is very quiet and doesn't disturb my sleep. A bit scary to cut a hole in the roof but well worth it!
Also looking to add some sort of vent. The question is are there and re-inforcing 'rib's in the roof you want to avoid. Basically as all have said its a super design I just need a cooler sleep environment.