Purchased the tankless waterheater to replace my exsisting waterheater. Received this item quickly. Had it installed in just a few hours and am now enjoying the benefits from this system. The only problem that I have noticed is that it does take just a few minutes longer to warm up, and sometimes I will loose the warm water in mid flow, but really is not a problem. We have two of these type of waterheaters and I am hoping that I will see an annual decrease in my utility bill. Overall a great buy.