How can I find out what the Energy Rating is on my Reliance 501 w/h?

Reliance is AO Smith company.
http://www.reliancewaterheaters.com/prod/gas.html
http://waterheatertimer.org/Water-heater-manufacturers.html

1) Reliance does not post the 501 manual any more and I've written and asked for that manual, and they sent generic manual. Model 501 is both gas and electric.

2) That tells me the old energy factor is probably lower than .54 approximately, but it will be even less because energy factors are for new water heaters in perfect operating order under ideal conditions.

3) Energy factor is a measure of how efficiently the water heater turns energy BTUs into hot water.
Gas water heaters have higher energy factor because gas burner has more BTU punch than electric element, and can heat water faster.

4) However, energy factor is not measure of actual cost. It is merely a way to compare giant water heaters with smaller heaters, and gas with electric, without considering cost of heater, installation cost, repair costs, parts costs, life expectation of unit, disposal/recycling cost, or replacement cost.

5) You can improve your true energy factor by buying small cheap heater and maintaining it yourself so it lasts many years beyond manufacturer's warranty.
http://waterheatertimer.org/Replace-anode-rod.html

6) If someone buys a bigger water heater because it has better energy factor, it will not pay back the higher purchase cost. Same size to same size, the difference with higher energy factor is a few dollars per year.
http://waterheatertimer.org/How-to-install-gas-water-heater.html

7) If you have sediment inside of tank, the energy factor is out the window.
http://waterheatertimer.org/Clean-sediment-out-of-water-heater.html

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