First heater was DOA - bit of an aggravation since there's no way to test it until it's installed. Amazon resolved my problem by immediately sending a new unit which worked like a champ. While it comes with a flow reducer (0.5 gal/min) I didn't install it. Didn't need it. Live in VA where the average cold water inlet temp is about 60*F. This thing has no trouble getting it hot enough to wash your hands comfortably. I'm sure it wouldn't work in a shower, but I've got it serving a garage deep sink and powder room. Great purchase. Wiring and connections appear to be of very high quality. Good mounting template and instructions. Would definitely recommend to friends and family.Update: There's a "feature" about this unit that isn't well documented and caused some initial grief (after replacing the DOA one). Turns out there's a tiny impeller in the inlet coupling/line inside the unit that needs to move freely up and down its shaft. The purpose of this is to trigger a relay to turn the heater on/off. Impeller up - water is flowing and pushing it up its shaft to make contact. Impeller down - absence of water flow inhibits the heater from turning on. Nowhere in the documentation is this described or mentioned. No big deal, right? Wrong. If you get any debris (say PVC dust or glue from the installation or junk from inside the original plumbing) inside that inlet, the impeller will likely not move freely up and down. That happened to me and in my case, the heater never came on. After about a 10 minute call to the company, I realized I had to completely uninstall the unit (a plumber installed it and didn't use any compression fittings, so everything had to be cut away and reinstalled) in order to clean this impeller. Good idea to let your water run and flush anything out before hooking it up to the unit. Wish I had known about this design before installing. Doesn't change my impression of the product or my rating, just something that could have been mentioned in the installation instructions.