I quoted what is on their website. You can check it out. Rob is a carpenter. Maybe he misunderstood what you were asking. No upfitter puts black and grey tanks inside the van and there are very few instances of freshwater tanks inside. I can tell you my first week with an ARV van in 2015 I went a full 7 days with constant below freezing weather day and night and boondocked the whole time caught in a polar vortex in January culminating in an overnight in a Walmart parking lot in Gallup, NM that got down to zero degrees. My new ARV which I havenít gone through a winter yet is better. ARVs are all lithium ion batteries of over 400ah with second alternators and the heating of tanks and batteries are all 12V directly off the batteries and it doesnít take much and you drive just about every day which most do in cold weather and stop with batteries topped off at 100% SOC. Heating and hot water comes from Rixen Espar diesel-fired with glycol heat exchange.