[azatris]

I've used a Japanese toilet and for me the hand washing facility attached to it is meaningless as I do not understand why would anyone ever wash their hands with cold water. Especially I do not understand people who simply wash their hands by dipping them into cold water for a second.

But maybe the culture of washing hands with warm water and soap is merely in North Europe. And maybe I am illusioned by the effectiveness of warm water.

edit:// English correction

[jimeuxx]

There was a little study about this last year I believe [1]. Most of what comes out of your A is happy living at 37°C, so I'm sure it doesn't mind an extra 3°C or so.

[1] http://www.tested.com/science/life/459452-doing-it-wrong-hot...

[rainedin]

It's suggested that there is no benefit washing your hands with hot water with regard to hygeine.

http://www.smithsonianmag.com/ist/?next=/smartnews/2013/12/w...

I pretty much always wash my hands with cold water, unless they are especially grimey. The only advantage is that hot water seems to work better with soap, which may help dislodge dirt easier.

[ekianjo]

> why would anyone ever wash their hands with cold water.

Well it depends on the time of the year. In winter, you certainly don't use them that much because water is freezing cold. But as soon as it turns april-may, water becomes lukewarm or even relatively hot in summer months (summers are excruciatingly hot in Japan), so then it's not an issue anymore.

> And maybe I am illusioned by the effectiveness of warm water.

Do you mean warm water is more effective at washing ? There's actually no basis for that. Surfactants matter more than temperature.

[DanBC]

The standing water is likely to be more worrying than the temperature of the water.

http://www.cdc.gov/handwashing/show-me-the-science-handwashi...