I looked it up in my native language - as to get localized results - and it seems like the general manufacturer's recommendation here in Sweden is to connect the dishwasher to the cold water, making any prewarming of the water unnecessary here.
I guess different advice for either side of the Atlantic is warranted, same as with washing machines - it's basically not possible to run a washer here with cold water as far as I know, you can only run it at 30 °C at the lowest, where the washing machine will heat up cold water to that temperature itself.