I installed one of these units in my Chesapeake Virginia home about two years ago. I moved and rented the property a year later. The N210 is great "when it works", however, reliability is an issue. Three weeks ago my tenants informed me that there was a problem with the hot water. I went and checked that all electrical connections were tight, and reseated the optocoupler microcircuits on the controller board. The unit worked for another two weeks and then failed again. The manufacturer says that, if I send them the unit, they will refurbish it and give me another 1 year warrantee. That's great... but what are my tenanats supposed to do for the week (or so) that the unit is at the manufacturer? The regrettable solution was to remove the N210 and replace it with a tank type water heater. The N210 had replaced hot water created by an oil fired boiler, so refitting for a tank type water heater required re-plumbing again! I am getting pretty good with a torch and copper.