"Phil Sherrod" wrote in message
...

On 30-Mar-2004, "Lou" wrote:

Temperature rise for water: 53 degrees F (114 - 61)

Um, not quite. The temperature differential your heater is maintaining
is
53 degrees. The temperature rise for the water is the difference
between
temperature of the cold water coming into the tank and the hot water
coming
out. The air temperature in the vicinity of the tank doesn't tell you
what
the inlet temperature is - it could be warmer or cooler

My analysis was to measure the energy loss for an IDLE water heater.

Right. So you're not measuring the cost of the water temperature rise.