On 2006-07-11, DesignGuy wrote:

However I noticed that the Rheem has a rating of 75500 input BTUH, and the
Kenmore has rating of 55000. I'm not clear if a lower or higher number is
better, as some explanations I've read seem to indicate that the Rheem would
use more BTU's to heat the water than the Kenmore (thereby making the
Kenmore more efficient).

Is my reasoning correct or is the reverse actually true?

The reverse is probably true. The BTUH rating doesn't tell you
anthing about efficiency, it just tells you the rate at which the unit
can draw and burn gas. If the units are of comparable construction,
they likely have comparable efficiencies. In this case, the higher
BTUH unit will simply reheat its hot water tank faster after hot water
is drawn out of it.

For efficiency, look at the water heater's "ER" rating. This will be
a number between 0 and 1 that basically tells you how much of the
theoretical energy available in the gas the water heater burns
actually makes it into heating the water. It reflects inefficiences
in the burner itself as well as standby losses from the storage tank.

Cheers, Wayne