I set it to high and left it to run for 8 hours checking every hour or so. At the first hour it was warmer inside but not cozy. To be fare it took 2 hours to get it cozy inside where the other would take 15 minutes but it got the temp up to 80°f. This was from a cold frigid start and gave me a greater than 50° swing.
I know from showing up at our cabin in the winter after months away the building itself is cold. Starting the wood stove puts hot air in the room but it is absorbed by the structure and must equalize before it gets cozy inside. Once you hit that point it doesn't take much to keep it there.
I mentioned insulation... I insulated only the ceiling and floor of our camper. With the inside temperature at 80°f for over 8 hours and outdoors in the mid 20s with everything covered in snow and ice enough heat could not escape to melt the snow load on the camper. When I started I was certain I would see excessive melt but I observed none. Excellent! While insulation in the walls would be better it's not required to be very comfortable.
I think the ceiling is where you get the biggest bang for your buck. Let's call it essential. This has also been proven in a Texas summer cooling the camper down.
These pictures were taken after the 8 hours.
I'm curious on others opinions, I am always one of those where more is better, why use a tack when you can use a 3" deck screw? At the end of the day there is an acceptable baseline.