Info on gas vs electric costs?

Hi,
Where can I find some info and maybe a calculator to determine the relative annual costs to run a water heater. I have gas, normal venting but the next one has to be either power venting gas or maybe electric. I am trying to determine if a power venting gas will recoup the higher purchase price as compared to electric.
Thanks,
Gary

1028 BTU = one cubic foot of natural gas.
1 BTU = 0.2930711 watt/hour

you need to know your energy costs. Gas is usually per 100 cubic feet or a therm, which is close to that (don't know the conversion).

An electric is close to 100% efficient; a gas-fired system will lose some heat up the flue - anywhere from 50-90+ % efficient, depending on the design.

A power vent gas is more efficient that one that needs a flue, but they do cost more money.

Here is a table that compares the different types:
http://www.aceee.org/consumerguide/waterheating.htm#lcc

The energy rates are in the footnotes.

heater

Unless you are in a heavily subsidized area, such as the TVA, electric is seldom cheaper than gas.

Your local gas and electric utility companies can give you operating cost estimates for all types of appliances.

You also need to look at your utility bills to determine your true costs. For example, while my electric rates are 10c/kwh in the summer, but they drop to 4.7 c/kwh in the winter (after 800 kwh). Gas bills can be equally confusing, some have a relatively low per therm fee, but have a high fixed customer charge. While others charge a high per therm fee with a low fixed fee, which can affect the numbers if you use gas for other things. Unfortunately, there are no easy comparisons. If your looking at the energy star numbers on the yellow tags they are based on 64 gallons day (average household 2.2 people), the average family of 4 is closer to 100 gals a day.