I have a rambling 1885 Victorian house in New York City, with long domestic hot water branches, requiring long wait times for hot water to arrive, not good!My first plan was to install two dedicated DHW return lines, requiring installing 1/2" pex lines connecting to the kitchen on ground floor, and to the third floor bath. This traditional solution means the DHW is being circulated in a loop, making hot water always available at the tap. Great system, but a lot of work!This Grundfos UP pump was a good solution for me. It meant that I could avoid all the work involved in putting in two dedicated "loop" DHW return lines - because it uses the existing cold water supply line as the "loop" to push hot water and make it available when you open the tap - BOOM!I was skeptical that it would actually work, but after installing the system I can report that it works very well!I find that when you open the tap the water is not "fully" hot, but it is warm enough for washing your hands, and the most important thing, you are not waiting for the cold water to become warm and/or hot. After ten seconds or so, the water is measurably hot, certainly hot enough for washing dishes or doing the things you normally do with your hot water!The installation was a snap, I would recommend that you install gate valves above and below where you mount the pump coming out of your HW heater, that will make it easy in future if you need to change the pump or get it serviced.On the comfort valve part that is mounted under your sink, just use stainless steel hoses *(the pump kit comes with 2) which have rubber cone shaped washers so that you just have to tighten them down to the valve, without using any pipe dope or teflon tape on the threads.We'll see how long these valves last in daily use, I'll report back if there's any issues.Overall a good product and innovative technology designed to save energy and water!