Most dishwashers do need to be connected to a hot water supply. Dishwashers are typically designed to use hot water for cleaning, as it helps break down food particles and grease stuck to dishes more effectively. Hot water also ensures that detergent dissolves properly, leading to better and cleaner results. Some newer dishwashers come equipped with built-in heating elements, so an external supply may not be a requirement. These models can increase the hot water’s temperature even further, or take in cold water and heat it to the required temperature on their own(1).
So it’s worth asking, does a dishwasher need to be connected to hot water? For dishwashers with built-in heaters, a direct hot water connection isn't strictly necessary, but it can still improve efficiency, reducing the time and energy needed to heat the water. If your dishwasher doesn't have a built-in heater, connecting it to a hot water line will be crucial. Be sure to check your appliance’s manual to understand its specific needs. In most cases, a reliable hot water connection ensures that your dishwasher performs at its best.
(1)https://www.maytag.com/blog/kitchen/do-dishwashers-use-hot-water.html