One of the guys in my office has designated himself the "green agent" and actually did a presentation about these in our last team meeting.  He presented a product made by rinnert or something like that.  The system definetely did have possiblities.  The research he did said the gas models were super effiicient but the electricty didn't show much savings.

Thanks for the info,  I've had a little time to do a little more research, but would still love to hear from a few people who are actually using them

David, 

 I have 5 installed at my office, home and rental properties. They can work very well, but there are some installation issues, I've put together this page about tankless water hater installation problems and how to avoid them.

good info, thanks

Michael,

 Thanks for the great info in your link,  that really made me slow down and plan the process even more. 

Have a great year.