I JUST sat down after installing a Majestic propane direct vent fireplace. It's super rad. I was set on wood stove, a friend even gave me one, but for where the bus is parked and how often i need to come and go, propane is a good fit.
I did a lot of research and like mentioned propane ventfree just puts off a ton of moisture. I read 1 cup for every pound of propane. That's too much for me especially since i am in Virginia where it is always high humidity.
Did a rough install today to get a feel for it. I always try to get something just good enough and sit with it for a bit before i invest a lot into construction, in case i change my mind, or realize something isnt going to suit me. Better i barely completed it when i take it apart than do a full install and sit down and go "oh crud, this wont work."
A considerable amount of heat exits the vent, where as ventfree all the heat stays in the bus. Prefer tot be efficient as possible. I was surprised how well it radiated heat on low. Still have some kinks to iron, and may move it to the next window bay for a better fit. Also need to make a permenant vent cover.
Here is a picture
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