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120 second shower challenge

Wednesday, January 7, 2015

Being a ‘mega fan’ of Soap and Glory products  I came across their idea for a 120 second shower whilst browsing their website. The theory and motivation for this being that Soap and Glory encourage people to take long luxurious showers whilst using their products. The aim of 120 second shower is that one very quick shower once a week would make up for the long ones….or would it? I wanted to take this to the extreme, how much hot water could you save in a week if every shower was carried out like this? Is it actually feasible to shower in this amount of time?

Instructions for a 120 second shower

Soap and Glory’s instructions for the challenge:

  1. Tap on – For 40 seconds and to warm up and get ‘all over watered’.
  2. Tap off – While you suds,scrub, shave, shampoo.
  3. Tap on – To rinse for 40 seconds (we know, that some of you have long hair)
  4. Tap off – While you massage in conditioner (if you use it)
  5. Tap on – For a final 40-second rinse.

Nicola’s shower diary


As I washed my hair at the weekend and have no need to break out my legs, all this morning’s shower consisted of was a ‘body wash’. I didn’t do the whole turning the shower off and on thing this morning as I wanted to see how long a ‘body wash’ takes, as I didn’t think it would reach the 120 second mark! I was correct 95 seconds gone and I was reaching for the towel!


Today I thought I best get to grips with the on/off showering that Soap and Glory recommend, as my hair needed a good wash. Today’s shower was complete in 137 seconds, only 17 seconds over the recommended time. Today I didn’t find the shower particularly enjoyable as without the shower running it got pretty chilly whilst soaping up.


I was on to a winner this morning 75 seconds! My fastest shower yet, even though I shaved my legs. I didn’t find the turning on and off as frustrating as yesterday, mainly because I only had to do it once.


Today I was so half asleep when I got in the shower I completely forgot I was supposed to be doing research! tI definitely took longer than 120 seconds judging by the amount of steam on my bathroom window! I should also add that I washed my hair too… even worse! Sorry – I’ll get back on with the research tomorrow!

I promise I am not in prison!

I promise I am not in prison!


Today was 83 seconds. It wasn’t a shave or hair wash day, so being cheeky I didn’t do the on and off procedure. I simply enjoyed a constant warmth from start to end and showered very quickly.


Since I slept in this morning and didn’t need to wash my hair, today’s shower was complete in a very speedy 52 seconds.


Hair wash day is back again! Now I feel like I’ve mastered this on-off procedure, spending only 115 seconds in the shower. Turns out practice makes perfect.

Reflection on the week

120 second is achievable, however it does take some practice getting your shower routine down to a fine art. Things like having somewhere to rinse your razor whilst shaving is helpful, as usually I’d rise it under the shower. I also found it to get very cold if you spend too much time wet with the shower off e.g. whilst shaving.

Now for the energy saving – how much water, energy and money did I actually save that week?

Total shower time (during challenge) 677 seconds
Flow rate of my shower 1 litre per 10 seconds
Total amount of water used 67.7 litres
Total time for a ‘regular shower’ (inclu. hair wash) 240 seconds
Time time for 'regular shower: just a wash' (no hair) 110 seconds

Given I usually wash my hair 3-4 times in an average week on a weekly basis my regular showers would use:

240 x 3 + 110 x 3 + ((240+110)/2) = 1225 seconds → 122.5 litres.

The difference between the water consumed during regular week and the challenge week would be 55 litres and if this was extrapolated over a year would be equal to 2860 litres.

Looking at my water bill → 2860 litres = 2.860 cubic meters. I’m charged at 129p (water) and 160.7p (sewage) per cubic meter. So over a year, this would give me a saving of £8.29 based on water consumption alone.


Next I set about calculating the cost of heating a litre of water. This proved difficult! As the water that comes out of my shower is a combination of hot and cold water from my boiler it is incredibly hard to calculate exactly how much ‘hot water’ is used.

Using science however, I can get a rough estimation of the energy used to take generic tap water ~10°C up to the average shower temperature ~30°C.

For a temperature increase of 20°C (assuming no losses in the system – even though there will be many!)

For 1 litre of water….

1L  of water = 1kg assuming it’s pure!

Using the equation for specific heat capacity

Energy (J) = mass (kg) x specific heat capacity (J/Kg°C) x change in temperature (°C)

= 1 x 4181 x 20

= 125 kJ

As our energy bills are measured in kWh rather than kJ….

125kJ = 0.034kWh

See our previous Know-How piece on kWh for further details on this conversion!

Assuming 2860 litres per year, it will take a minimum of 97kWh to heat the water. Remember this is for a 100% efficient system, meaning i’ve assumed there is no heat loss through pipes, lack of insulation etc.

At 15p per kWh, this at least £14.55 a year to heat the additional water for my shower.

In total over a year I could potentially save £23 continuing with 120 second showers!

Remember this is for me alone. If you’re a family of 4, you have the potential to save at least £100 per year!

Will I be continuing and would I recommend the experience?

I’d definitely recommend everyone give this challenge a go for a week. It was really interesting to see how much I could save by using the stop/start method of showering. I think it would be much more suited to the summer months as my bathroom would be warmer. In the future I’m definitely going to be more conscious whilst showering and think to turn the shower off or at least down to a slower flow rate whilst shampooing etc.

Now over to you! Take on the challenge and see how much you’d save following the Soap and Glory 120 second shower! The measurement of the flow rate was done with my kitchen measuring jug and stopwatch – this is something you could easily do yourself to work out exactly how much you could be saving!

Have you got an energy challenge that you’d like us to undertake?  Get in touch via Facebook or Twitter.

Disclaimer: This blog is not endorsed or sponsored by Soap and Glory. Nicola is just a really keen fan who wanted to test out their theory to see exactly what the energy and cost saving would be!

  • Nicola Lazenby
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    Nicola Lazenby
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