On the subject of dishwashers, I came across this video a few weeks ago which does an excellent job of explaining some of the....'bugs'....associated with modern dishwashers.
https://www.youtube.com/watch?v=_rBO8neWw04&ab_channel=TechnologyConnectionsTL;DW:
-Dishwashers are connected to the hot water supply which can be a waste because the water in the tub is usually cold by the time the dishwasher is ready to draw it. If you want to ensure the water is hot going into the dishwasher, run the kitchen tap until the water out of the tap is hot BEFORE starting the dishwasher cycle.
-Dishwasher 'pacs' are a waste, at best they're just standard detergent, and at worst with how some models dose the pacs you might actually be getting very little detergent in the main wash cycle.
-You should always add detergent to the pre-wash cup (all dishwashers have them, and if you think yours doesn't, the indentation on top of the detergent chamber is for pre-wash dosing).
-You really shouldn't pre-rinse residual food, it's just a waste of water. The dishwasher will macerate and discharge the big stuff in the first cycle.
So now I’m curious if those who wash clothes on cold also use cold water in their dishwashers? Why or why not?
The only way to get cold water in most dishwashers is to connect it to the cold-side supply. The amount of hot water the dishwasher draws from your water heater is a rounding error on your utility bill relative to a bath or shower. In the first rinse cycle, hot water is especially important to help melt off any fat/oil before the main wash cycle is initiated.