Each winter, we get around to discussing how to heat the interior of the van
(Westy) while camping.  Coleman has a product (5033-700C, I think ) that I
just bought from Canadian Tyre for about CDN$55 plus two gas cartridges for
CDN$2.89 each.  It is portable and can be moved around the van.

The box says:

20 cm (8 inch) Platinum Catalytic Head
Propane - no pumping or pouring
Silent "flameless" regulated portable heat source (454 deg C (850 deg F)
3,000 BTU/h output
Up to 8 hours on a single 465 g (16 fl oz) disposable cylinder
Match light
Designed for indoor use

The directions warn against hooking it up to a 'regular' propane bottle.

So I bought one and used it on last weekend's winter camp out in beautiful
Cape Bretton (Nova Scotia).

It is whisper quiet, 3,000 BTU/h is not enough to heat up the van to shirt
sleeve temps, but it did keep my Westy about 8 degrees above the outside
temp:  when it was -2 C outside it was +6 C inside.  This was warm enough
if we kept a jumper (sweater) on.  We did get about 8 hours on a fuel
canister - 4 hours at night and 4 hours in the morning.  It lit very easily and it
was great to light (from the lower bed) prior to getting out of bed on those
cold mornings.

I could not find the product at www.coleman.com but you can try 1-800 835-
3278 (USA) or 1-800-387-6161 (CAN).

For those of you who want more than 3,000 BTU/h ------- buy 2 of 'em!!!

Malcolm