> What CO problem Rob? The product of combustion is H�O. All you need
> to do is have a vent to allow fresh air to enter and the excess moisture
> to exit.

Gotta chime in here,

The CO problem that has been responisble for killing many people from
using an unvented catalytic heater in their vans or RV's.  How do you know
how much fresh air needs to enter?  It may be okay to use while you're
awake but sleeping with one of these things on is downright stupid.

Andrew Fox
86 Westy w/ plat cat vented catalytic heater that kept me warm  and
alive camping over 20 nights last winter in sub-zero temperatures.