Will be installing MaxxAir delux fan front half of roof area. I will not have any windows that are able to be opened except for driver and passenger windows. I don't want to open those windows for air intake as there is no screen and rain can get in. My thought was to install one or two screened air intake vents in the floor somewhere toward the rear that could be opened and closed. This would give an air path from lower rear to upper front with air that was coming from the shade underneath the van and rain couldn't get in. Shouldn't be any exhaust fumes problem as I don't plan on using the fan except when parked with engine off. My twin bunks will be forward in the van. Anyone do something similar. Am I missing some obvious reason this is not a good idea? My wife say's I am prone to this. Thanks for any advice.