Washing Hands in Hot Water Wastes Energy, Study Says
It doesn’t kill germs better than cooler water, but turning tap temperatures high, the U.S. burns carbon equal to the emissions of Barbados.
Carrico said, "It's certainly true that heat kills bacteria, but if you were going to use hot water to kill them it would have to be way too hot for you to tolerate."
She explained that boiling water, 212°F (99.98°C), is sometimes used to kill germs-for example, to disinfect drinking water that might be contaminated with pathogens. But "hot" water for hand washing is generally within 104°F to 131°F (40°C to 55°C.) At the high end of that range, heat could kill some pathogens, but the sustained contact that would be required would scald the skin.
Carrico said that after a review of the scientific literature, her team found "no evidence that using hot water that a person could stand would