System Efficiency

Brstr

I am looking for any documentation that might lend itself to help convince people that AFUE is not the end all in fuel savings. I work in a state that requires an installer to be licensed to install any heating appliance that is over 200,000 btuh. This leads to many contractors using several water heaters to replace older oil boilers. They are basing this decision on the acclaimed 95% AFUE of the gas 199,000 btuh water heater. I am hoping to gather documentation that would help convince people that the proper equipment, ie; a Boiler, would prove to be more efficient in the long term.
Thanks in advance for any help!

Howard Emerson

Here's a link

http://www.bnl.gov/est/files/pdf/ButcherAachenPaper.pdf

PS-As you've surmised, AFUE has little to do with boiler for heating/domestic hotwater mile-per-gallon, so to speak.