Sears 33154 (marketed as Kenmore but made by AO Smith) FHR=97 EF=0.63
(41,045 btu/0.63)($1.21106/therm * 1 therm/100,000 btu) x 365 = $288/year
Home Depot 183-717 (marketed as GE but made by Rheem) FHR=80 EF=0.58
(41,045 btu/0.58)($1.21106/therm * 1 therm/100,000 btu) x 365 = $313/year
I read the article you referenced at
http://www.waterheaterrescue.com/pag...intenance.html
It doesn't say WHERE the 41,045 BTU number cames from.
What is this "magic" number of 41,045 BTU?