Power shower use quickly uses more water and energy than baths

November 30th, 2011 by Unilever UK and Ireland

A study by Unilever UK and Ireland is the first to reveal what British families really get up to in the shower. The findings will enable scientists to help consumers to save energy, water and money.


Using innovative new technology, developed at Unilever’s Port Sunlight R&D laboratory, researchers are now able to monitor actual showering behaviour, rather than relying on self-report which, until now, has been the only way of understanding consumers’ shower antics.

The Sustainable Showering Study is the first ever to record accurate data on how we shower and provide a benchmark for the environmental and financial impact of this. The findings reveal:

  • The shower vs. bath eco-myth: The average shower is eight minutes long and uses nearly as much energy and water as a bath. Showering costs the average UK family £416 a year
  • Average power shower could cost UK families £918 per year: An eight minute power shower uses nearly twice as much energy and water as taking a bath
  • Young boys are the worst offenders for lengthy showers: They spend an average of 10 minutes in the shower, washing away the notion that they can be a bit grubby
  • Women are miles better multi-taskers than men; even in the shower
  • Not all results are surprising: teenage girls really do monopolise the bathroom

The study used an innovative Shower Sensor to monitor 2,600 showers taken by 100 families, over 10 days – totalling 1,000 days of research. The Sensors recorded when showers were being used and for how long. Throughout the study, participants also kept shower diaries to track who was showering and what they did. These shower diaries also gave Unilever scientists the opportunity to monitor the differences between actual and reported showering behaviour by running a separate self-report survey.

The study provides a unique insight into what Brits get up to behind closed bathroom doors and reveals the impact our behaviour has on our pockets and the planet.

It supports Unilever’s commitment to growing its business while reducing its carbon footprint, as set out in the Unilever Sustainable Living Plan, which was introduced last year. Unilever scientists will use the insights to design new products and other solutions to help consumers save money by conserving energy and water.

Dr Hilde Hendrickx, a behavioural psychologist at Unilever UK and Ireland, said: “Around 95% of the greenhouse gas emissions associated with our shampoos, soaps and shower gels come from people using hot water, especially for showers.

At Unilever, we know we have a responsibility across the entire lifecycle of our products, not just in our factories but when people enjoy them at home as well. To reduce the environmental impact of product use at home we need to better understand how people use their showers. But this is a challenge as we obviously can’t watch them and we know that self-reported behaviour is often not very accurate. So we’ve developed new technology that enables us to do this.

“This study will help us start to understand what the catalysts are for changing people’s behaviour in order to reduce the amount of energy and water they use during showering. It will also enable us to shape new products and other solutions to deliver savings in energy, water and money, both for us and our customers. This sort of work is vital if we are to grow our business while reducing our environmental footprint.”

While previously people have talked about the five minute shower, The Sustainable Showering Study reveals the real figure is much higher with the average shower duration at eight minutes. An eight minute shower with an average water flow rate uses around 62 litres of hot water (compared to 80 litres for a bath) and costs around £0.30. That’s a total of 90,000 litres per year for the average four-person family, at a collective cost of £416.

The financial and environmental impact of taking an eight minute power shower is even greater: it can use up to 136 litres of hot water per shower, which is equivalent to nearly two baths, and costs around £0.63 per shower.

That’s a total of nearly 200,000 litres of hot water per year for a typical family at an average cost of around £918.

The findings bust the eco-myth that showers are always better for the environment than baths. In fact, the fastest flow shower recorded by the study, used as much water as a bath in just 4 minutes 42 seconds (17 litres per minute).

Young boys are the worst offenders for taking very lengthy showers, according to the study, helping to wash away the notion that they can be a bit grubby. Boys aged 12 years and under actually spend longer than anyone else in the shower, at around ten minutes on average. The longest was a whopping 30 minutes, despite the fact that the boy only washed his hair and body in that time.

shower water droplets (click image to expand - ©RLLord)

The study suggests that women are very effective multi-taskers, even when they’re in the shower. It reveals that while women and men spend a similar amount of time scrubbing up, women are busy undertaking multiple activities in the shower, such as hair washing, shaving, and cleaning their teeth while men just seem to enjoy the experience.

However, not all of the findings will come as a surprise. The study revealed that young girls aged 12 and under take short showers of around six and a half minutes. But when they hit their teens they start to spend one and a half times as long in the bathroom. The average teenage girl takes nearly nine and a half minutes in the shower, costing her parents around £123 a year.

Unilever has a successful track record of using factually based behavioural insights to reduce its carbon emissions. In its research into laundry trends, a study observed that people consistently used more washing detergent than they needed. It identified an opportunity to reduce product packaging by creating concentrated detergents with smaller caps, making it easier for people to use the correct amount. The result was less plastic packaging used, fewer lorries needed to transport the bottles and reduced product wastage.


Sustainable Guernsey comments that this study has particular relevance to Guernsey because of our limited island supply and our growing demand.  Even when Guernsey experiences heavy rain, our small water table and our large water demand can quickly draw down the level of water in our reservoirs. If Guernsey has a season of dry weather the island can quickly develop a water shortage.

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