Don't bother turning on the hot tap next time you wash your hands. Water at 15 degrees or 38 degrees seems to do just about the same job.
New Zealand's Ministry of Health, like many other health organisations worldwide, advises people that warm water is best for handwashing if it's available.
But researchers have shown that washing your hands in cold water will get them just as clean; it removes similar amounts of bacteria and will also save on power bills.
