I have just finished installing the HotRodAir unit in my 54 f100. It works great on A/C, Heat and Defrost. Now for the question: I am thinking of installing the RodDoors underdash unit with the hide-a-vent option. Has anybody else done this? How does the heater vent get air out of the bottom? How about the vent air when you open the cowl vent? I understand that I can buy a remote electric operator, but how does the air get through the underdash cover? Is there a vent built into it for this purpose? Do I need to just install my own vent(s)? Any insight would be greatly appreciated. Thanks, John in Sacramento