I don't disagree with lurker but to be fair, taking the word of "aproned staff" on any water heater design considerations, regardless of brand, would lead to the same poor answer. That does not mean that Rheem does not address the altitude in their design. They do. High altitude models have an "H" in the model number and have either a smaller gas orifice or, in the case of a powervent model, a different blower motor.

To your actual question regarding efficiency and cost to operate:

The Rheem you selected has an energy factor of 0.67. I could not find the energy factor published for your Bradford White model. Can you find the information on the plate? If you can find a date of manufacture there, that will provide an indication of its efficiency as well, since requirements became more strict on April 16, 2015.

@Alice,

I didn't take the word of the aproned staff. Just illustrating how little the aproned staff knows about what they sell... especially when that product can blow up your house or waste lots of your money. I contacted both manufacturers.

BW made a different model of mine available for sea level, up to 5k ft, 5k to 7k, and above 7k and that was clearly marked on the box and WH label. Took 4 minutes on the phone to get this answer from BW

Rheem made one high altitude model available that they say is correct for "up to 10k". Took 21 minutes on the phone to get this answer from Rheem.

With that wide a range the Rheem will only burn correctly within a narrow window of altitude and burn less efficiently at most altitudes.

Anyone with experience with pre fuel injection internal combustion engines and air density knows you can't jet to burn correctly over that wide a range of altitude. Just to be sure I ran this by the tech at my LP company, who jets LP appliances to burn correctly at altitude every day, and he agreed the appropriate BW was going to burn more efficiently than the Rheem.

Thanks for your feedback. I will keep that in mind. I could not find the energy factor on the machine or on their website.

Manufacture date? If the date is after April 16 of this year, the BW will be cheaper to operate. I would call the manufacturer and ask them. The BW could be anywhere from $60 cheaper to operate per year to $50 more expensive to operate per year (assuming 100 gpd hot water usage). Either way I would leave it, but you may have different priorities.

great tip, thanks