The Showering Habits of the Great British (Un)washed

Yesterday I was asked by the BBC News online to comment on an innovative piece of research by the FMCG giant Unilever. Unilever have recently launched their Sustainable Living initiative and as part of they have been investigating people’s most intimate habits –  that is ‘what exactly goes on in the bathroom’??

They rightly point out that self declaration on bathing habits, and even diaries, can be inaccurate for a number of reasons – the fact that people want to say the right thing and look good in the eyes of the investigator, or simply that people are pretty bad at estimating time when an action is totally habitual and unconscious.

So those cunning scientists at Unilever came up with a technological solution.  They attached shower monitors onto the hot water pipes in 100 UK family homes, and monitored exactly what went on in the shower cubicle each morning.

The results are startling and a little depressing.  Although 4 minute showers are encouraged as an optimal time in which to get clean, but not to use too much hot water; the families in the study were routinely using double that!  And, less surprisingly perhaps, young boys and teenage girls were the worst offenders in terms of time spent under the shower rose.

There are a few things about the Unilever findings that I do not agree with though.  They talk rightly about the fact that power showers can use as much water as a deep bath if too much time is spent under them, but they then quote some enormous figures in terms of how much money this might cost the average family of 4 to run each year.

For a ‘standard shower’ (although exactly what that is is not clearly defined) – they say it could cost an average family of 4 around £416 per year just to shower.  Now this seems rather alarmist,  if we take a standard ‘electric shower’ (46% of installed showers) as the example, then the average electricity bill in the UK currently is around £550.  So they are claiming that the shower alone could be accounting for 80% of the bill.  But if they are refering to a standard gas heated mixer shower (38% of installed showers), the number gets more far fetched – as the average gas bill nowadays is around £850 – so showering would account for half of that total.  Given that a rule of thumb is that heating water is responsible about 30% of our heating bill (~£275), and that includes all washing and use of taps etc – then that number seems far too high for an ‘average’.

There there is the £900+ for a power shower.  This is realy taking an extreme example and presenting it in a way that makes it sound like a possiblity for the average home-owner.  Power showers were only 16% of the installed shower market in 2007, so they are by far the minority technology.  They are seen to have a pump rate of between 10-20 litres per minute.  To arive at such a high cost, Unilever much be taking the scenario of a very high flow rate and each of the family having 8 minute showers each day.

Also the average use of water per person per day in the UK is 150 litres.  This is unnecessarily high and we have a target to reduce that to 130 litres over the coming years, but if we take the extreme example that Unilever is using, each family member uses almost that on showering (17 litres x 8 minutes =  136 litres) alone.

It could be that Unilever are somehow factoring in the water costs too, but if so it would be interesting to see how this has been done.  As you can only make a saving, or spend more, on showering if you are on a water meter.  There are currently approximately 30% of homes on meters, and the costs of water vary enormously around the country; hence I would question the validity of adding a water cost to this ‘average’ price of showering.

So, I salute Unilever for this ground-breaking study and alerting people to the issue of longer showers not necessarily being better – environmentally or cheaper to run – than a bath; but I do mark them down for being too extreme with their figures.  We need to educate and bring people along with us on behaviour change issues; we should not try to shock people with unrealistic, atypical worst case scenarios presented as ‘average’.


2 comments… add one
  • Joe Jones December 8, 2011, 2:51 pm

    Thanks for this thought-provoking article. This issue highlights to me how easily we can absorb 'truths' – such as 'showers use less water than baths' or 'actually, showers use more water than baths' without really questioning the evidence base.
    In a similar vein, I only heard recently that dishwashers typically use far more water than washing up by hand. Apparently the original claim (that they save water) was based on tests comparing them with washing up under a continually-running tap. 
    I like to think of myself as very rational, but it's amazing how easily we allow myths that validate our preferred behaviour to go unchallenged! The consequence of challenging this one might be having to do loads of washing up…

  • cumfy June 28, 2012, 7:32 pm

    For standard 10kW showers and 14.5p/kWh-1 this would correspond to 12 minutes per individual.


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