If you decide to install your heater underneath the van floor you have several options where to locate it but here is one to get you started. Hope it gives you a good starter for 10...
Van model in the photos: VW T5 (2013) UK model
Heater location: directly under drivers seat floor, protected by plastic under-body covering
Cold air intake: vertical wall of side step at drivers door
Hot air outlet: through the floor at the base of the seat belt column at rear corner of drivers seat
Extra fittings required: Under Body Mount Bracket:
First read the complete MV Airo fitting guide we have prepared for installation inside the drivers seat base. It includes all the information about hooking up the electrics and fuel supply. This page is just some extra advice about locating the heater unit underneath your van floor.
Here's an overview of how it fits together: The heater is fitted on its side, so that all the exhaust, combustion pipes and fuel inlets are facing sideways - towards the centre of the van. The bracket is bolted upwards to your main chassis bar.
And here is where it all sits in relation to your under-body plastic trays etc:
You can pipe the hot and cold ducts where you want but here's one example:
NOTE: THE SMALL ROUND COLD AIR INLET GRILL SHOWN IN THIS PHOTO (IN THE STEP) IS NOT INCLUDED IN THE KIT
Underneath your van it looks like this: