"Elmo P. Shagnasty" > wrote in message
...
> In article >,
> "Nancy Young" > wrote:
>
>> > The water doesn't care what generated the heat. During the heating
>> > season, that heat is going to come either from the dishwasher heating
>> > element or from the furnace, but either way you're going to pay for
>> > the heat. It may be marginally cheaper to use the furnace, if you
>> > have an up to date high efficiency furnace, but not enough to notice.
>>
>> ? The dishes dry themselves whether I have the furnace running
>> or not.
>
> The furnace heats the house. The heat in the house is used to evaporate
> the water.
>
> The house heat that is used up by evaporating the water needs to be
> replaced. Where does it come from? The furnace.

This is true, there's no free lunch... you can't use the same energy twice.