I'm trying to set up a safe heater for an 8'x20' cabin. The cabin is based on a standard steel container. I want one that doesn't require electric, and exhausts any fumes to the outside. I'm in the process of insulating at R9. This is in Missouri to give you an idea of the temperatures involved. It was 16F this morning, but I probably wouldn't be using the cabin if it were much colder. 

I have access to a wood stove, but that's really too big and hot. I have a catalytic heater, but that requires leaving a window open because of the use of oxygen. 

An ideal soluton, if I could find it, would be a very small kerosene heater that would install on one wall, or better yet, like a window air conditioning unit. The heat would go inside, but the fumes outside. I haven't yet seen anything like that. I have seen a larger kerosene heater in an old Maine house that sat on the floor and exhausted through the wall, so a smaller, wall-mounted version of that is what I'm envisioning.

I want to avoid fire hazards and fumes. It could be kerosene, or some alternative.