Bill is right that an un-vented catalytic heater will dump water vapor into
the interior of the van...enough to cause rusting from the inside out over
time and if used enough.  I hav e the 3000 BTU platcat and have camped in
below zero temps with it.  If the van is insulated (including the windows), it
is enough to keep it very comftorable for sleeping, assuming you use balnkets,
too!  the smaller size is nice, too.  I have a photo fo my portable set-up for
the vented cat at http://www.concentric.net/~Sxs/SyncroPage.shtml
steve

William Dummitt wrote:

> I've tried both a catalytic heater and a Propex heater in a Westy. Both
> were 6000 btu and both did a fair job at 20-30 degrees.  They were more
> effective if the poptop was not up.  I don't think a 2800 btu heater would
> be adequate, based on what I've seen.
>
> The catalytic heater I've used was a vented model from Thermal Systems.
> Unvented heaters can sometimes cause condensation problems, but judicious
> window-opening might circumvent this.
>
> Bill
> www.geocities.com/yosemite/gorge/1706