OT(ish) - lies, damned lies and ballet dancers (Grauniad)

Warning - long ramble.

Interesting use of statistics.

"The average 10-minute shower uses 60 litres of water. A power shower uses three times that and a bath about 80 litres. So a family of four each having a daily 10-minute power shower (I know that is a very conservative estimate for some teenagers) will consume a staggering 0.25m litres of water every year. The annual average cost for electricity for four 10- minute showers per day would be up to about £400, or £1,200 if a power shower is involved. Even worse, the power-shower family would be emitting a staggering 3.5 tonnes of CO2. As we can afford only one tonne of carbon emissions per person ? for everything from food to transport ? if we are to keep global temperatures below the critical 2C threshold, this would consume nearly all of the family?s carbon budget."

For all you DIYers, some of these figures may seem a little strange.

"The average 10-minute shower uses 60 litres of water"

Well, at 6 litres per minute this must be a pretty feeble shower - although I sized our combi to heat 15 litres per minute so it could service two showers. However that was 15 litres of hot water, and doesn't count the mixed in cold.

has some rule of thumb figures, but my brain started to hurt trying to compare everything.

It does say of power showers "A 12 minute shower with a flow rate of 15 l/m would use 180 litres of water." which seems to tie in with the "three times" figure for normal vs power shower.

Using Google for bath volume, I find from 2011 which seems to be remarkably similar to this 2016 puff piece but with the opposite spin.

Although it has an 8 minute shower using 62 litres of water.

Using the site from above:

"According to BS6700 a standard 1700mm x 700mm bath uses approximately 100 litres of water at 40?C. This is split into 60% hot and 40% cold water when hot water is stored at 60?C." So about 60l of hot water from store or combi.

But, of course, the variable volumes are only the start.

"The annual average cost for electricity for four 10-minute showers per day would be up to about £400, or £1,200 if a power shower is involved"

Note the words "up to" - often used in shop SALE signs as "up to 50% reduction" where all but one item has only 5-10% knocked off.

We (like many others) have a gas combi boiler which provides our hot water. I am struggling to see how I use anywhere near £400 (or £100 per person) when I shower using a mains pressure gas combi.

On flow rates, the Triton Aire fitted to our bath has a maximum flow rate of 15.5 l/min at 1 bar (or 8 l/min with the flow limiter fitted). I've grumbled in thread passim about the seemingly weedy flow. Not yet measured it but 6 l/min for the average shower does seem slow.

Googling for flow rates for electric showers doesn't seem to turn up much from the manufacturer, however:

says "For a 8.5KW or 9.5KW Triton showers the minimum required water pressure is 1.0 Bar with a minimum flow rate of 8 litres per minute. A Mira 8.5KW or 9.5 KW showers only require a maintained water pressure of

0.7 Bar and 8 litres per minute. This is one of the primary reasons we always specify a Mira shower over Triton."

Which suggests that 6l/min is too low for your average electric shower! However to give an electricity cost of £100 per year per user they must surely be using an electric shower (or possibly immersion heater?).

O.K. - well into a long ramble.

Anyway, so far we may have established that the minimum flow rate for a modern electric shower is around 8 l/min, and DIYers may well note that electric showers are generally held to be not very good compared to a tank or combi system, which suggests a satisfying shower could require 10 l/min even with an "Economy" shower head.

TL;DR I am a little surprised that the average (I think) flow rate for a shower at around 10 l/min would fill the average 100 l bath in 10 minutes. Then again although shower time is an alternative Universe I don't think I spend an average of 10 minutes under the shower.

I leave the "Even worse, the power-shower family would be emitting a staggering 3.5 tonnes of CO2. As we can afford only one tonne of carbon emissions per person ? for everything from food to transport ? if we are to keep global temperatures below the critical 2C threshold, this would consume nearly all of the family?s carbon budget." for the dedicated environmentalists on this NG to debate.

Pro tip - "Get out of that shower, Jennifer, you're destroying the planet!" may have more moral high ground than effectiveness.

Oh, and don't use soap because this ex-ballet dancer once met someone who had a bad reaction.

Cheers

Dave R

Reply to
David
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The "average" 10-minute shower?

They made that bit up, I'll bet.

Like 27.4% of all statistics. :-)

Reply to
Mike Barnes

David quoted:

If I put the plug in while having a power shower, the bath is about half full by the end, not flooding the bathroom as that suggests ...

Reply to
Andy Burns

Am I the only person that has, out of interest, put the plug in the bath waste, and had a shower in it? I use a bit more water having a shower than I do a bath. Having said that, once I'm in the bath, there isn't much room left for any water :-)

Reply to
Dan S. MacAbre

It's the Grauniad. It's arsewipe.

Reply to
Huge

formatting link

"According to the study, the average eight-minute shower used 62 litres of hot water, and some power showers can use up to 136 litres, compared with an average bath's 80 litres. ...

Our own research shows that a 'waterwise shower' ? getting the job done in four minutes under a water-efficient showerhead ?uses just 32 litres."

If I have a bath, I often let some of the water out, so I can run more hot in. I wonder whether that's been allowed for?

So, let me see, it all depends on: How big a bath, how full you fill it, and whether you refill it. How long a shower you take, and how powerful the stream of water is.

Who could possibly have expected that? :)

Reply to
GB

So my guilt (ha, ha) at having regular baths is totally ill-founded, they only use 30% or so more water than tha average shower?

Reply to
cl

However probably fuller than you'd have a bath surely. I generally have a bath deep enough to cover my legs (with me in the bath) so that's probably rather less than 1/4 full.

Reply to
cl

If I have a bath, the water always comes up to the overflow (with me in it).

Reply to
GB

Or rather, failing to get the job done and causing the user to throw the useless piece of junk out and buy a proper shower head ...

Reply to
Huge

Why are you in the overflow?

Reply to
Huge

No. I did it years ago. Got about 2" of water - I would need at least 6" for a bath.

Reply to
Jethro_uk

ditto.

Reply to
Andy Burns

In message , Dan S. MacAbre writes

Absolutely not. Good to soak the feet whilst showering. As someone else said, a couple of inches of water. What I can't understand is why wimmin take so long, even without the dreaded hair washing episode. I just get in, quick twirl to wet the bod, apply soap, another twirl to rinse, water off, out. How difficult can it be?

Reply to
News

Personally, I use about 200L per bath, soaking tub.

Reply to
Capitol

Electricity consumption with a power shower? Can you get all electric ones?

Reply to
Dave Plowman (News)

In message , News writes

You missed shaving their legs.

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Reply to
Tim Lamb

Saves the need for a plug in the bath. Ever.

Reply to
Dave Plowman (News)

Immersion heater for hot water plus power shower (we are trying to make these figures as bad as possible remember)

Reply to
Chris B

THat, would be telling.

And then I'd have to shoot you.

Reply to
The Natural Philosopher

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