Today’s post is based off a National Geographic Daily News article that my dear friend, Billy, sent to me as an idea of what to write about. Apparently, washing your hands with warm water doesn’t kill germs any better than cold water does, and its actually much more energy inefficient. The typical American on average washes his or her hands seven times a day. Most of the time, the water used for hand rinsing runs at a temperature between 104°F and 131°F. It isn’t until the water nears 131°F that the heat of the water will start to kill some germs. However, for those germs to be killed, one would have to leave their hands under the running water long enough that their skin would end up being scalded.
According to research done by Amanda R. Carrico, an assistant research professor at the Vanderbilt Institute for Energy and Eniovnment in Tennessee, it was found that as long as hands were scrubbed, rinsed, and dried off properly, one could kill bacteria using water as cold as 40°F. Since, according Carrico, “no evidence that using hot water that a person could stand would have any benefit in killing bacteria,” using such high temperature of water is both unnecessary and wasteful. When Americans wash their hands they use water much hotter than necessary 64% of the time. “Although the choice of water temperature during a single hand wash may appear trivial, when multiplied by the nearly 800 billion hand washes performed by Americans each year, this practice results in more than 6 million metric tons of CO2 equivalent emissions annually,” she said. Putting that into perspective, that 6 million metric tons of CO2 equivalent emissions is more than the greenhouse gas emission of El Salvador, and about the same as the level of emissions of Barbados. That is a crazy amount of energy-related carbon emissions that we could reduce if only American’s got in the habit of washing their hands with cooler water.
Now, the fact that this article is from Billy is slightly ironic since this is the boy who ran out of hand soap in his bathroom and was too lazy to replace it. So for over a month, he would “sanitize” his hands by running his hands under as hot of water as he could stand. Turns out that probably didn’t do too much… (Sorry Billy, your secrets out!)