As we’ve written before on this blog, there’s more pressure that ever on organisations to save water and reduce their carbon footprints. One way to significantly reduce the environmental impact of of your washrooms is to switch to cold water only for hand washing.

Many people believe that there’s a hygiene benefit to washing hands in warm water, but research has shown that that’s simply not the case. In 2017 scientists at Rutgers University in New Brunswick, Canada, showed that washing hands in cold water was just as effective at removing germs as washing using warm water.

Washing hands in cold water removes just as many germs as warm water

The researchers covered the hands of volunteers with harmless bugs, then asked them to wash their hands in water that was either 15C, 26C or 38C. They found that using water at a temperature of 15C, essentially cold water, removed just as many bugs as washing hands in water at either of the higher temperatures.

NHS guidelines in the UK state that people can wash their hands in either cold or hot water. The key thing that determines hand washing effectiveness isn’t the temperature of the water but the length of time spent washing (at least 20 seconds) and ensuring that the whole surface of the hands is covered with soap.

Warm water isn’t hot enough to kill germs

This makes sense. In order to be able to actively kill germs, water would have to be heated to close to boiling point – that’s the temperature of the water in your dishwasher, or of water used for sterilisation of medical implements – which would clearly then mean that it could not be used for hand washing. The warmth of water at a temperature comfortable for hand washing is nowhere near hot enough for the temperature to play a role in killing germs. It’s the soap that’s doing the work, not the water.

Cold water is better for your hands

There are other advantages to using cool water for hand washing. Repeatedly washing your hands in water that’s too hot isn’t good for your skin – exposure to hot water can irritate and damage your skin. Ironically, such irritation makes your hands more vulnerable to infection and germs. So, using cool water is better for your hands.

The environmental impact of heating water for hand washing is significant

Switching to cold water for hand washing also has a significant environmental benefit. Heating up water is an energy intensive process. Heating one litre of water by one degree requires just over 4 joules of energy. A typical hand washing process involves using 3.25 litres of water and heating it up by 29C (from an ambient temperature of 10C up to average hand washing temperature of 39C). That’s an energy requirement of almost 400 joules per hand wash. If you assume 1,000 people might use your washroom in a typical day that’s 109 KWh used per day, or almost 40,000 per year. Switching to a tap that uses only cold water cuts out this energy cost completely.

Additionally, users often have to wait for water to heat up to their desired temperature, meaning that taps are left running for longer than necessary and much more water is used than actually needed. It’s an inefficient process whichever way you look at it.

The Swiss Eco Tap reduces water use by 90% and energy use by 100%

Sometimes we talk to clients who are concerned that, despite the obvious environmental benefits, users prefer warm water for hand washing because it’s more comfortable. That’s why we recommend the Swiss Eco Tap, which uses only cold water but has a special spray technology that means there’s no feeling of coldness on the skin.

The unique spray-pattern aerator jet ensures that the water does not feel cold to the user, even though only cold water is used. Instead the water jet produces an optimal sensation of cleanliness when washing hands and leaves a pleasant feeling on the skin.

Additionally, this spray technology means that the Swiss Eco Tap uses much less water than a traditional tap but achieves the same cleaning result. In fact, the Swiss Eco Tap uses an incredible 90% less water than traditional taps, less than 0.5 litres per minute compared to one litre every five seconds for standard taps. Cutting water use by 90% and energy use by 100% makes it the world’s most sustainable tap.

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To find out more about how the Swiss Eco Tap can help your organisation to save water and money, call us on 0844 800 7890 or drop us an email.

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