I purchased a SETS model 280 after being impressed by their web claims of helping 911 responders and their affiliation with NASA.It was comparable in price with other well know companies, "built in the USA", and I wanted to give them a chance.
Big mistake! Not only does it NOT produce the advertised constant flow of a constant water temperature, it burned me and my credit card. The company flat out refused to do anything other that give me the run around and feed me lame excuses as to why it doesn't work. I wasted over $2000 getting their water heater professionally hooked up, over $700 on the unit itself, and hours trying to get any help out of these clowns.
Read the fine print on the bottom of their page, NO REFUNDS FOR ANY REASON, they say that for a good reason, they know what I know now. Look at how many different websites they advertise under, read the other reviews they don't post of these sites, do your homework.
Whatever you do, DON'T BUY A SETS!!!!!IT SUCKS
Review about: Sets 280.