I just came across these direct-vent, fan-less, noise-free LP gas heaters (i.e.
not ventless, and
not catalytic - both intake and flue are outside) and was wondering if anyone had seen one working, or considered putting one in their trailer. I do not know if they are RV-certified (but would find out)... but as far as I can tell, this would be as close as you get from the good old fanless furnaces that manufacturers used to put in.
Empire Millivolt Direct-Vent Wall Furnaces