Water Heating/Dishwashers

Fully load the dishwasher. It takes as much heated water to wash a partially full dishwasher
as it does a fully loaded one. Install low-flow pre-rinse spray nozzles.
 

Set the water heater thermostat no higher than it needs to be: 140°F for dishwashers, but only 110°F for hand washing.

Consider gray water heat recovery. If your dishwasher is a continuous fill and drain, consider
installing a gray water heat recovery system. This system will recover some of the heat from the drain water and use it to reheat the supply water to the appliance.