With all due respect, as you are a vendor of Chinese-made RV products it is understandable that you might not be aware of American-made Earthroamers, their systems, their insulation and their cold weather performance. I am neither a vendor of any sort nor am I affiliated with the Earthroamer company. However, before making a claim of "almost 0 insulation" one might consider picking up the phone or sending an email to Earthroamer to see what sort of insulation they're using. Earthroamers have been in production for roughly a decade and a half. There are multiple models and the design and construction of the camper body has been evolving the entire time. The current LTi model is carbon fiber [which may or may not be a great development, IMO]. The standard insulation that is bonded to the camper shell is between 1.5 and 3" of PIR or similar laminate board. There is perhaps better insulation out there (aerogel would be interesting) but PIR is easy, lightweight and adequate. The windows (nice and handy, though plastic, dual-paned German-made Dometic) and multiple vents are the weak points in the insulation, not the body. The heating sources are more important: heating over the years has been provided by 1-2 diesel Espar Airtronic D2 or D5 units, hot water heating is via a Hydronic D5, and an Indel/Webasto Isotemp or Kuuma marine grade 6-10 gallon electric water heater that is tied to the vehicle coolant system and the Espar hydronic heater (resulting in 3 ways to provide hot water). There is also a 2-burner Webasto diesel range ceramic cooktop (not really for heating though it would probably work to keep the frost at bay in a pinch). I can definitely see the pros and cons of the Earthroamer (and GXV/Adventure trucks), none of them are perfect, but if I were a vendor in this space, I would collect some facts before positing inaccurate information about another vendor in the "Expedition Vehicle" business, if only to be professional. Earthroamers have their faults (e.g. the newer, longer-bodied XV-LTS vehicles are heavy and quite close to the F550 GVWR...maybe a less than ideal trait for a 4x4 camper...and there have been multiple wheel bearing failures, etc.) but staying warm and comfortable in cold/extreme cold conditions is not one of them.
What would be really interesting is to see an Earthroamer, a GXV Turtle and Adventure truck (I know they're different vehicles with different prices and capabilities) do a long trip, maybe Deadhorse to Ushuaia or simply trans-AK/Canada in winter and see how they do though like every vehicle, it comes down to driver experience and capabilities, especially in cold weather.