Dishwashers are designed with lots of clever little sensors to optimise their performance, but they’re not always helpful.
Many dishwashers can automatically ‘sense’ the water temperature and continue to run water until it decides the water is warm enough to start a new wash cycle, which can mean an extended (and therefore more expensive) washing cycle.
Use less energy and water by giving your dishwasher a head start: Before you turn on the dishwasher, run hot water for 10 seconds from the tap nearest to the dishwasher. Heating the water in the pipes should shorten the running time of the dishwasher.
This doesn’t work for every dishwasher, but it’s worth trying – check the time difference between a cycle done with pre-warmed cycle, and one done from cold – if it’s shorter, that’s your answer!