On Sun, 10 Feb 2008 21:20:35 -0700, Rick Blaine wrote:
Hint: Direct energy cost is based on _use_ and efficiency, not _capacity_ and
efficiency.

Good point ... dead capacity vs active usage!

Darn. I wish I understood this EF thing better, especially given two
identical situations where the *only* difference is the CAPACITY.

Based on what you implied, if I inferred correctly, if the USAGE was
exactly the same for two water heaters with the same EF, then the costs to
operate a 50-gallon water heater would be EXACTLY the same as the costs to
operate a 100-gallon water heater (if the Efficiency Factor were the same
for both).

Did I understand the math (and your point) correctly?

Donna