"It is possible to insulate the outside of a shipping container instead of the inside.
This method of insulation is known as “over-cladding” or “external insulation” and involves adding a layer of insulation to the outside of the container before covering it with cladding or other weather-resistant materials"
Seriously? It's surface area to volume problem. You have this tiny box. And then you have problems with doors, Hvac, etc. Sorry but the whole idea is idiotic.