When burning propane, do ventless heaters generate water vapor as a by-product of combustion?

Question

I'm curious as to wether the water vapor comes from the burning process, or if it is just condensed from the existing moisture in the air.

Answer 1

Plain and simple, Yes....

It is more noticeable with extended use based on the fact that humidity is reduced by increasing air temperature. Once you reach the point at which you are maintaining a temperature rather than raising it, you will notice a marked increase in humidity while using vent free heaters.

It is for this reason, and this reason alone that all Vent free heaters warn that they are not intended as a primary heat source. Carbon dioxide output on approved vent free heaters is negligible; Oxygen depletion is also made irrelevant by use of the ODS pilot assembly

Answer 2

The burning process generates water and carbon dioxide.