I need to upgrad a small cistern system I have on my cabin to one that needs to supply enough water and water pressure for an on-demand hot water heater to a shower unit and a sink. Here is my set-up and my questions: I am in North Carolina where the winters don't get very cold but there are cold snaps and the temperture gets down to 19 degrees. I want to prevent freezing. The cabin will be used the entire winter by 1 person so I need to have access to hot water daily, everyday. I would prefer a tank on the ground, but am opened to suggestions. I have electricity but don't want to spin the needle wildly on the power meter. I have access to water from a near by house that will allow me to fill the water tank (150 feet away.) But I don't want to have to do that too often. Everything needs to outside, because I don't have a basement or an attic. So, what I need to know is what do I need to make this all happen? It sounds like I need the tank, a pump, the bladder tank ...what size would work and where can I learn how to do this? Thanks