Hot and cold....used both, had two sealed units shatter to pieces in the past water was at least 60 degrees, only go as high as 40 degrees when I use it now. Big difference, easier, quicker, preferred choice anyday!
Q. ask yourself when your cleaning the dishes, wine glasses and pots and pans after a sunday roast would you find cold or hot water shifts or loosens the stubborn dirt easiest. If you filled two coffee or tea stained mugs, one with cold water and one with hot, didn't scrub them with a cloth or dish brush but just gave them a swill around after a minute and emptied the water you would discover the mug that had hot water in would have removed most if not all of the drink stain at the bottom better than the one filled with cold water......try it for yourself.