On Sun, 16 Mar 2008 20:27:22 -0400, Don Wiss wrote:
There is no convenient chart to distinguish the models.

Yes there is.

The whole reason I wrote up my water heater saga was so that others benefit
from all the help people here gave me. One of the references in the thread
was the recent DECEMBER 12, 2007. CONSUMERS' DIRECTORY OF CERTIFIED
EFFICIENCY RATINGS for Residential gas, oil, and electric water heating
equipment.

http://groups.google.com/group/alt.h...na+ohl&lnk=ol&
Mon, 11 Feb 2008 10:54:32 EST

In that reference PDF are the efficiency ratings for the hundreds of
residential hot water heaters sold in the USA (under a handful of
manufacturers but scores of brands).

I challenge you to find a water heater efficiency rating NOT in this
36-page listing for a water heater currently sold in the USA.
http://tinyurl.com/38eh4d
(long url)
http://www.gamanet.org/gama/inforeso...vAttachmentLau
nch/C2AAFB8D41D003F485256E9000607F66/$FILE/12-07-gas-rwh.pdf