Hot water costs more money than cold water, that much is true. However, hot water cuts grease, kills germs, cleans more effectively and works better with most soaps and detergents. Not using hot water can cause you to have to change the water more often to prevent grease. You may need to scrub dishes more, risking damage. Cool water or even warm water will mean you have to dry dishes by hand, and if you change the dishtowels as often as you should to prevent cross contamination, you'll have clothes to wash as a result. All in all, hot water saves time, energy, and resources. Hot water is a necessary part of getting dishes clean. There are energy saving tips for washing dishes, but cutting the hot water isn't one of them.
Proper Water Temperature
Why You Should Use Hot Water
Practical Ways to Save Energy While Dishwashing

