Today, I washed my hands at the kitchen sink while making lunch, and was unexpectedly chastised by my partner because she had just started the dishwasher. Apparently, she has recently come across something that has convinced her that running the hot water in your sink means the water that enters your dishwasher will be hotter (checks out), and thus the dishes will be cleaner. I tried searching startpage to see if this is real, but I couldn’t make it through even one llm-slop-ticle about it before my eyes rolled back into my head, so here I am asking y’all: chat, is this real? Doesn’t my dishwasher have a heating element? Is there any meaningful difference between heating the water with a hot water heater vs a dishwasher, other than I can’t use my sink while the dishwasher is filling and I have to pour a bunch of cool water down the drain?
More than that, you will be pumping more water to flush the cold water from the line, which is more energy. You will use more water overall because that cold water will all be going down the drain. You will then have to heat up enough water to match the cold water you flushed from the line plus the water used to wash your dishes to reheat your water tank. If, from an energy/cost perspective, that is less than what it would cost for the likely less efficient water heater in your dishwasher to heat the water, then you have saved some money. If it isn’t, and your dishes are already coming out clean, then you are neither getting a better nor more efficient cleaning job done.