The US Department of Energy Website has lots of helpful information about how to conserve energy and lower your utility bills. They even have a handy dandy formula that allows you to estimate how much money you are actually spending to utilize various household appliances.
Formula for Estimating Energy Consumption
(Wattage × Hours Used Per Day ÷ 1000 = Daily Kilowatt-hour (kWh) consumption
(1 kilowatt (kW) = 1,000 Watts)
Multiply this by the number of days you use the appliance during the year for the annual consumption. You can then calculate the annual cost to run an appliance by multiplying the kWh per year by your local utility's rate per kWh consumed.
Now let's apply this formula to running your dishwasher for two hours a day. The chart from the website estimates that dishwashers, when applied through a full rinse and heated dry cycle, would typically apply a wattage of 2400.
2400 X 2 hours / 1000 = 4.8 kW
Now multiply 4.8kW by 365 days in a year and you have an annual energy usage from your dishwasher of 1752kW. The standard energy charge right now for LADWP is $0.07288 per kW for private residences. So at this usage, we can gather that you would be spending $127.68 a year in electric charges for your dishwasher, and that's not even addressing water usage. Now, if you were able to cut your usage down by only running the dishwasher when you have a full load every other day, you could cut your bill in half to $63.84. Moreover, a major portion of the energy used for a standard dishwasher goes toward the drying cycle. If you were to shut off the heated dry and take a few extra minutes to dry the dishes by hand , you could again cut your bill in half dropping from the original $127.68 to $31.92 a year. That makes for an overall savings of 75%. Now who doesn't like a 75% discount!? Beyond that, you might even feel good about yourself for helping the environment, which just goes to show once again that prosperity comes in so many more forms than having a big checking account.