Im a licensed plumber and have used rinnai in most applications. I like these because the settings are easy to deal with right on the front digitally. Slant 6 Dan is right that they wont kick on unless the minimum 1.5 gallon per minute is achieved. If you do use one i have only seen good results using gas. The biggest thing with these is the flushing. They must be flushed and reset every 6 months or they will shut there selves down. its a coil like a still and cannot transfer heat fast enough if allowed to build up calcium.I would use one in my own home if i couldnt get the wholesalers to give me freebie heaters for my own home when needed. Most faucets and showers are made to work at 1.5 gallons per minute so you can add it up and if youre gonna run less than the max of the heater at one time you will be fine.