The hot water washes the soap off faster and more thoroughly (and feels good on old and tired hands.)
The biggest problem with handwashing is that people don’t do it, or don’t do it properly. It won’t improve compliance now that facility managers have an excuse to turn-off the expensive water heaters.
If the water is cold, the washing is mostly symbolic. If it’s hot or warm I wash much longer and more thoroughly.
When I worked food service at a hospital, hand-washing with hot water was mandatory as a matter of policy. I will say that in the dead of winter, after having just come in to start a shift, hand-washing with hot water was definitely mandatory as purely practical matter. (And we still had a hard time making sure people washed their hands every time they were supposed to, the way they’re supposed to.)
I think it will take a long time for the policy manuals and administrative rules to catch up with the science though.
And also…
I tend to think the entire point of using hot water was never to kill bacteria, but rather because hot water is a better solvent than cold.
“Although the perception that hot water is more hygienic is based in some factual evidence…”
Erm, so I’m confused: they have seen research saying that it IS actually better, from an evidence-based hygiene perspective, contrary to the headline. May not be better energy-wise, but that’s not the claim. Poor writing Smithsonian. The CDC does concur that temperature is not a helpful factor http://www.cdc.gov/handwashing/show-me-the-science-handwashing.html and have references for the research, but the original papers are not freely available, it seems, so I can’t see the methodology. Once again we are left wondering why original research is not freely and easily available to the public.
Review the subject of the sentence, and it makes perfect sense.
Who the heck thought they were killing bacteria by handwashing, anyway? (Answer: all those people who’ve gone gaga over anti-bacterial this’n’that. Ah well.)
The point of handwashing has always been to wash off the bacteria, not to kill them and leave the corpses in place. And hot water is observably better at cleaning stuff off your hands than cold. (Try this: change your oil / change a tire / whatever gets your hands greasy and grimy. Wash your hands with soap and cold water. Then do it all again with soap and hot water. The results speak for themselves.)
Warm water is good, since you’ll wash more thoroughly. Hot water is bad, since it will dry your hands out more. Which is important when there you have to wash your hands often.
I thought the warm water was to help the soap penetrate fats/oils just a little quicker/easier so you don’t have to wash for so long to get good effect?
There is more to washing one’s hands than killing or removing bacteria. What about other dirt? We have here a case of being misled by what is not being said.
Those are exactly my thoughts - everything dissolves better in warm/hot water, so logically washing in hot water will more thoroughly and effectively clean an object, whether hands, body, clothes, car, floor, cutlery, carpet or dishes. As well as the aforementioned glory of warm water on cold hands.
I anyone helps me pirate this http://www.ncbi.nlm.nih.gov/pubmed/15824636 that would be much appreciated.
Since handwashing temperatures are well within the range used to proof yeast and culture bacteria, this lack of bacteria killing is unsurprising to me, but I would be surprised if hot water being a better solvent didn’t matter.
Hot water washes off sugar and denatured proteins faster than cold water. I’ll keep on using hot water, if you don’t mind… 
Redd Foxx would be proud of me. I got a Toto Washlet.
You know how they say that the best exercise routine is whatever you actually do? Regardless of any study, I’m going to continue to wash my hands with comfortably warm water and old-fashioned soap. If the water is too cold or too hot, I’m less likely to wash my hands, and I refuse to buy anti-bacterial or foo-foo fancy scented soap. I’ll stick to Ivory or the generic equivalent, thanks.
Damn environmentalists. It’s the depths of winter. I’m not going to start washing my hands in (ice) cold water. Doing so might put me off frequent hand washing.
