If you have electricity I believe this is the safest and best way to heat a teardrop.
It comes in two sizes: 24" X 24" and 18" X24"
I have the 18" X 24" unit which is 240 watts. It is installed on the wall between the cabin and the galley next to my wife's feet. It is 1/4 inch thick and is 1/2 inch off the wall and 3 inches off the floor. It does not get hot enough to combust anything. I have an outlet on this wall and I plug in a thermostat and then plug the unit into the thermostat.
You set the temp for what you want and it maintains it.
My td has 3/4 inch foam board in the walls, 1 1/4 inch foam board in the ceiling and 3 inches of foam board in the floor.
We have only camped in temps down to 20 degrees, but the unit maintains the temp at whatever temp you set.
It is a very soft indirect heat that does not lower the humidity of the air.
It works great for us as we never camp without electricity.
Larry
http://www.royaltystudio.com/products/E ... 20J98.html
this is the link to a thermostat similar to the one we use with this heater.
http://www.newegg.com/Product/Product.a ... PAodHm0AvQ