from the manual that i downloaded VAPOR: A By-PRODUCT Of UNVENTED ROOM hEATERS Water vapor is a by-product of gas combustion. An unvented room heater produces approximately one (1) ounce (30ml) of water for every 1,000 BTU’s (.3KW’s) of gas input per hour. Refer to page The 300 ml you claim would be more appropriate for a 100k whole house unit for 2000 sf, not a 75 sf van. please note- **30**, not **300**ml. ** ANY** propane hrater gives off water vapor, its just the nature of the beast. I hope this was an honest mistake, a typo, and not a continuing effort to be dissagreeable with me, as it appears to be at times. Damp rid, crack a window, proper insulation, controing your breathing, move to a more temperate climate all help with moisture buildup.