2 questions about ventilation.

1. When a class 8 motorhome is driving down the road and it's 90 degrees outside, how do you cool down the interior of the cabin of the motorhome? Do the roof top units cool the cabin and are they powered from the trucks alternators or do they run off the auxillary generator?

2. When a class 8 motorhome is parked with all motors off and it's mild outside, say 50-70 degrees, is there enough ventilation through the windows so when you are eating, lounging, sleeping...you feel comfortable or do you need to run the ventilation system via the aux generator to get more air moving around inside the motorhome cabin?

It's really a simple question. I'm just having a difficult time explaining it.

I guess my questions are:

what powers the ventilation system and how is natural ventilation through the windows when not moving?

Any comments, suggestions...Thanks

Dear Bravestdog,

You will find that most use the aux genset to power the roof or basement airs when driving and when parked without an external power pole available.

At 90*, you may find that a/c in the rear is not that necessary with roof vents and a couple of windows open, but then again, I live in Arizona so I am used to the heat.

Your question about the natural ventilation will depend upon how many windows can open and how many roof vents there are and if they have a good fan such as a Fantastic Fan unit. You can also leave the door open with the screen door closed.

Peter.

We definitely run the ac's off the generator while traveling. Usually only need the front AC for the living area and I would run the cab AC for me.

My 8kw diesel generator had 2 30 amp circuits and this was plenty of power for my setup. We did not have a inverter to run AC items off of coach batteries, always ran the generator. I guess if you ran your rig all of the time and had people who just wanted to watch TV than a inverter would be good, but most of the time your gonna need to run AC, heat strips, microwave, ect and you would need to fire the generator anyway. My generator sipped about .6 gallons of fuel an hour and the Kubota motor will run 10,000 hours without even batting a eye.

As for ventilation go with MaxxAir vent fans, they are 12 volt powered. Run at least 2 of them and you can have 1 blowing out and one blowing in and you will have tons of ventilation. The reason I like Maxxair over Fantastic is you can run them even if it is raining.

Bill