I have a 240URS with the Arctic Barrier. I have camped in below freezing weather, overnight, enough to know when it helps and when not to around 27 degrees. I have no issues as long as I keep the inside temps around 64+ degrees with furnace running. I run hot water, cold water also, on occasion as the hot water lines run next to the cold water lines which keep the cold water lines from freezing. The extended low drain lines, fresh water drain line and gray/black water drain might freeze up on occasion but the inside water lines didn't. I boondock a lot. I also Remove the panel under the couch so hot air blows on the water pump to keep it from freezing. I have had the Fridge drain line freeze up but a hot soaked rag around the fridge drain and low water drains thaws them out pretty quick. I wouldn't camp with continuous freezing weather all day for days but overnight till noon is not much of a problem.