Robert SansomBack in my grandparents’ time, baths were infrequent and showers were just another word for rain. It wasn’t until after the Great War that bathrooms became a standard feature of new homes, but even then a bath was often taken no more than once a week and then when they were only really needed.

With the role out of North Sea gas and the wide scale installation of central heating in the 70s and 80s, the supply of constant hot water facilitated a step change in our washing habits. Showers came along but were little more than rubber hoses pushed onto taps with a spray at the end.

Then purpose built showers began to be installed and daily showers are now the norm with a third of the energy we use for heating used for hot water.  The EST report “At home with water” identified that showers are now the biggest water users.

However, whereas we can expect substantial reductions in energy consumption for space heating, there does not appear to be much we can do for hot water.  Improvements in wet appliance efficiency has helped considerably but any further improvements will probably be small.

If the trend in hot water consumption continues we could be using as much energy for water heating as we do for space heating.  This could amount to 10% of total UK energy demand by 2050.  That’s 200 TWh pa!

We could obviously just use less by not washing so much or not using so much water when we shower but I expect there might be some “consumer acceptance” issues here. So, isn’t there anything else we can do? Do we just have to accept that there is no alternative to our current regime of pouring 100 litres of hot water down the plug ‘ole every time we take a shower?  Is it really beyond human ingenuity to come up with an alternative?

Well a bit of internet research reveals that there are products out there.  It seems our Australian friends have developed showers that recycle the water (filtering it first you’ll be pleased to hear) and claim a 70% reduction in  energy and water consumption.  I also came across steam showers but I have no idea whether this saves or increases energy consumption.  What about some kind of control technology, could this help?  Why can’t I select an “Eco shower cycle” rather like I do on a washing machine for regular use and a longer cycle for occasional use.

I’m sure then are many other ideas that are far more imaginative and innovative but we just need to take this seriously.  We just need to talk about hot water.

Robert Sansom is a Researcher at Imperial College London funded by the UK Energy Research Centre.