I've done a couple of different types of heaters. I really like the quartz ones, but specifically the ones in a wooden box that you can use as a mini-table. The one we have we bought from Menards, I'm sure other places have them. It's just like the one in the picture above. I can tell you the wood never gets hot, barely warm if anything. It does have a LOW setting on it too, and thermostat goes down to 50°.
The key in my opinion is it moves more air than most fanless ceramic/oil heaters. (We also have a supplemental Mr. Buddy propane heater to boost the temp quickly, but the downside is it seems to generate a lot of humidity.)
Before our park model we had a 40' destination trailer with a 17' slide out, with maybe R-9 in the walls and ceiling. It had 7 foot ceilings and we could keep it around 60-65 inside with the quartz plus another small space heater (except when it got down to about 0, then the furnace cycled a few times).
This is the one I use to keep the chill out of the park model. It has several settings like anti-frost (32°) and night modes. Granted, the way I use it decreases its efficiency - I don't have it mounted on the wall, I built a 2x4 frame for it and it sits in the middle of the room. But it keeps the temp above freezing.
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