Aqua Hot was an $11,000 option when the rig was NEW. They aren't adding that much to price of the used rig. Aqua hot is a great heating system for an RV. You have all the hot water you want and you can run off shore electric in RV Parks. No need to refill a propane tank every week if you are running the heat. Aqua hot is just on of many items in an RV that is not justifiable if you are looking at whether or not you will save money having it. My rig had an optional paint package that was $5,000+ and upgraded cabinetry that was $12,000. Neither saves any money over time. Like those things Aqua hot is a luxury item, you don't expect to save money with it.