To get the tanks filled it was just shy of $50 per tank. Propane is worth 21,548 btu (I believe that's lower heating value) So a 100lb tank holds 2,154,800 btu $50. That's around 5 times the price of natural gas. We will say that's 43,100 btu per dollar. To compare to electrical heating you get 3,412 btu per kwh. Which translates into to about 36,000 btu per $1 worth of power where I am. A pretty big difference. But natural gas has 3 big disadvantages. You can't store very much of it (already looked into it), supply disruptions and that annoying surcharge you get during the summer where you pay $20 to $30 to use between $0 and $5 worth of gas. Electrical has 5 main disadvantages. You can't store very much of it compared to how much we use (already looked into it), making your own is really expensive and/or really inefficient, supply disruptions and almost everything depends on it to work. Let's say new Mexico the winter is really only about 4 months long. To get on the natural gas coop costs about $25 per month and they probably want a $500 deposit. So during the warm months I would be wasting $200 on surcharge. That would buy about 400lb of propane. My calculated propane usage would be something on the order of: The stove, if I hooked a propane stove up to a 100lb tank and only used it for cooking I could probably get a whole year out of a 100lb tank. The hot water heater: probably up to 300 lb per year. A propane heater in the living room: based on last year, probably use up to 120lb of propane per winter. To heat the living room based on last years 40lb tank usage if I used only propane I would burn about 150lb. Based on me and my sister living with my parents back in the day we used a 125 gallon tank for the range and hot water heating. We filled if up about once a year, in maine.