Catalytic or not, the heater converts propane (C3H8) and O2 to H2O and CO2.
Once the O2 level gets low, it makes H2O, CO2, and CO.  Bad news unless you
keep O2 coming in.  Even if you do, it still makes CO2.  CO2 doesn't bond to
your hemoglobin as readily as CO, but it still displaces oxygen in the van.

Also, consider that for every molecule of propane burned, 4 molecules of water
are produced.  That means you'll have unbelievable condensation and dampness in
your van after running all night.

This is why the furnace people go to great expense (passed on to you) to make a
heat exchanger with a blower, etc.

We'll stick with the $15 110VAC space heater.

-Karl
(MSChE with specialty in heat exchanger design)

Karl and Kristina Bloss, Trexlertown, PA
'87 Westfalia Weekender  "Beverley" - 190K miles
http://www.enter.net/~bloss/vw/
PA/NJ Vanagon owner's mailing list: http://www.enter.net/~bloss/vw/pavanagon/