DWeikert,
Try -13 to -15 F for more than one night in any TC or RV when it never got to even zreo during the day when boondocking for snowmobiling in the northern U.P. of Michigan in January or February. Also hit -27 F & -30 F on Drummond Island and in Ontario Canada near Chapleau and again at Ranger Lake at night also when boondocking in the TC.
+19 degrees is shirt sleeve temps compared to these! 30 to almost 50 degrees colder! All our Lance TC's have been very well insulated and I also have storm windows and a layer of Astro Foil under the air mattress but maybe you don't know what real cold is? However, if you really want to learn how to actually shiver, try it and report back!