Presently I have a wall-mounted, open-flame LP heater for supplemental heat in my upstairs bedroom. The upstairs is just the bedroom and the bathroom. Combined, they are about 700 square feet. They are normally heated by a heat pump. The LP heater is used only on really cold days when the heat pump can't keep up without engaging the extremely-expensive-to-operate heat strips.
The heater is not approved for bedroom use, and it is never run when anyone is asleep in the room. However, I would like to find an LP heater that can run during the night, if there is such a thing. A split system could be installed, but that's more than I want to spend for supplemental heating.
The question then is, what sort of LP heaters can be safely used in a bedroom? I realize local codes vary, but I'm more interested in safety than in codes. (Whatever is safe will probably be approved under the code.)