I have two of these. I've had one for over two years. It is designed for people totally off the grid; starts on 2 D cell batteries and then uses propane. Since I have a well we have to pay attention to the water pressure. Having people cooperate is a lot less trouble than paying to constantly heat a tank of water and have the thing rust out in no time.
Yes, you do have to maintain a certain level of pressure.
I have now installed the second one which is tied into the electric service for a starter then runs on propane.
The first one has been switched over to service the caretakers quarters and my 2nd level master bath.
The newer one services a one bedroom apartment, my 2nd level kitchen and the 3rd level bathroom.
Here's the secret to getting hot water in the shower: turn on the hot water in the sink, then turn on the overhead shower head, turn off the sink. The handheld seems to more restricted than the overhead rain head. I do switch to that for the final rinse and am finished before it gets cold.
I know, it sound like a lot of work but until we can find a way to remove those flow restrictors this works.
When I installed one in California about 15 years ago it was about $1,500 but it did service the entire house without a decrease in temperature. The last two cost under $500 each.
Yes, the water came out scalding hot and we reset it so it does not get above 120 - and believe me that is more than hot enough.
I say go for it and learn to manage.
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