Quote Originally Posted by Steve Smith View Post
I'm amazed at the size of the thing. In Europe, this would heat and provide hot water for a whole house without the need for header tanks or cylinders:





We (in US) have the type you mentioned (on demand heating type) also but they are not very popular. Mine is 40 gallon (144 liters) in capacity. I think the one OP has is even bigger. They serve as a hot water storage tank as well as being a heater.