So are the new ones just more efficient and need less gas... or do the
new ones have a lower recovery rate? (can not find stats on old
unit... new units have a recovery rate of aprox 40 gph.


What I learned (hopefully correctly)...
- BTU's do make a big difference in recovery performance.
- Efficiency numbers all take into account BTU's so it is OK to make
comparison of those numbers (same gallon size however).

What I did...
I picked out a High Recovery water heater that also has extra
insulation and a Mag rod (not alum.).
- Has 65kBTU rather than the standard 40kBTU.
- Energy Factor, Est annual cost, first hour rating, gallon
recovery.... all are higher/better than the standard water heater of
same size and Mfg/model family.

Bradford White, State, AOSmith each had comparable units as expected.
(OK maybe Bradford White had a slight advantage but only a lab rat
with a PhD could tell the difference in the real world.)

I picked a Bradford White product for two small reasons.
1) my plumber likes and can get a better deal on B/W because of repeat
business at his supplier.
2) The Bradford White has a Magnesium anode rod where the others had
Aluminum... and posts I saw said the Mag rods were better.

Thanks everyone for your help!
Dave-in-Denver