ctpres wrote:
Try this for getting your water boiled. No electric needed
Solar water heater
It probably has its niche, though I don't know where. Boiling 2 cups in it takes 2 hours. I don't think I would want to carry this "solar boiler" even on wilderness hiking and kayaking trips, not to mention Rv-ing.
It would take very little propane - and very little time - to do this on LP stove. One green Coleman cartridge of propane contains 1 lb (!), and it always lasted me more than 5 days in a tent, sometimes 8-9 days, with hot meals twice a day and countless cups of tea and coffee. 20 lb tank will last you several months, if used for stove only. It's fridge and furnace that are eating up most of your propane, - not the stove.