Is the shower really that more energy efficient than the bath?

Question

Depends on the duration of your shower I suppose. But all that hot water just going down the plug hole...

Is there a system that could recirculate the hot water until you are ready for the "final rinse"? I suppose you'd want a very good (and low maintenance filter system) for it to be a viable product. Cost wouldn't be an issue, because the system would have paid for itself in no time at all

Answer 1

So yes you are right that showers use way less water compared to baths, but what you are interested in is a closed loop bathing system. There are a couple of glitches off hand that I can think of with this system, but I do think it is a great idea and I am impressed with the brain storm --



1) You'd be sending those suds right back into a heater - unfortunately you don't want to heat up those suds because they will begin to break down and react with your hot water heater and might corrode your pipes, so you'd have to filter that junk out beforehand.



2) There isn't a filter out there except for the Reverse Osmosis filter (expensive, wastes water and high energy costs) that would remove all of the contaminants that you'd want out from the shampoos and soaps - there are a lot of estrogen mimicking hormones that you wouldn't want to drink up, so you'd have to keep it completely separate from the drinking water side of things.



3) After filtering things through you'd have to reheat this closed loop at the exact temperature preferred for shower usage. So you'd probably end up adding more fresh water just to get the right temperature.



4) Finally if you don't have a RO filter and you send these chemicals back through the loop you might breath a bunch of them in with the steam. This hasn't been tested and may not be healthy. It could in fact be toxic. Something to think about.



After all that safety and re-engineering it may be simpler and safer to send the gray water to either the toilet or to the garden. Although I really don't think there would be a problem with sending it to the clothes washer or the dish washer as long as you had that final rinse built in and no one ever peed in the shower! Best of luck! :-)

Answer 2

Several of the answers have directly and indirectly specified that the number of resources actually used determine which is more energy efficient, taking a shower or taking a bath. And, most of the discussion revolves around the "holding capacity" of a bath tub. - We did most of our growing up in a house with no shower; only the tub. One very direct benefit of a shower is that it takes less time. But, when your only source of "cleaning" is a bath tub, often you don't take the time to honestly fill the tub! And, even if you had the time to take in the morning, the rest of the house hold had their needs and wants too in terms of bathroom time and hot water volume. When you've only got a tub, there is a definite difference between taking a bath and taking a "soaky bath"!



In terms of energy efficiency, even a hot water tank draining, soaky bath could result in energy savings....If you were not sitting among the bubbles in the bath tub, what else would you be doing during that soaky bath time?



Again, the answer is based more in actual consumption as opposed to a simple answer of shower versus bath, one choice versus another. For every resourse use choice and its application, there is often more than just a simple yes or no answer, a pro and con, "efficientcy" versus "inefficientcy".



Whether you decide upon the shower or the bath solution - Do you further utilize any off-heating to heat the house in the winter while avoiding it to reduce cooling needs and wants in the summer? Do you consider using versus venting the bathroom steam with respect to the house hold humity? Have you considered using a bucket to collect shower or bath water for toilet flushing? - Even for 1 flush per day, if 1 million house holds flushed once with captured water , the savings would probably be at least between 1 and 2 million gallons per day. And, this can be done by home owners and apartment dwellers a like. - For many, the installation of an electric, in-line heater(s) versus/in addition to water tanks will use less water heating energy. At the same time, if your pipes aren't insulated with foam covers, they can go a long way towards energy conservation with less work and money. And, I would ask how much house hold heat do some folks use to warm up and/or keep the bathroom warm before using it? to what temperature do you warm it to? is there a more efficient solution?

Answer 3

Yes you are right it, depends upon usage. To be accurate you would need to know just how much flow your shower head is putting out when in use. "Low flow" shower heads can be as little as .5 gpm (gallons per minute) or up to 2.5 gpm. The term "low flow" is not as accurate as a rating. Additionally, such flows are measured at a specified pressure of 80 psi. Your pressure is probably less and if your shower head is partially plugged with debris is will be even less. One way to be sure is to take a 5 gallon bucket and measure how long it takes to fill it or how much is filled in a minute.



A standard bathtub holds 42 gallons to the overflow.1 But a person displaces some of that volume so the actual water used depends upon the persons submerged volume. Lets say it is 12 gallons of leg and hips giving us 30 gallons in the tub. With a .5 gpm shower-head you can have a 60 minute shower to equal the bath.2 With a 2.5 gpm shower-head you will have 12minutes.3 But the really old shower-heads were 5 to 7 gpm and that would only give you a little over 4 to 6 minutes to shower.



30% of our home energy bill is on average used to heat hot water.4 Any time we save hot water we are not only saving the water but part of our energy usage. Part of the reason we run the shower while we do the rest of our business is to stay warm. The plan below is to make the shower enclosure tight enough to contain the air and steam (and thus the heat) It includes a foot lever to more easily enable you to turn the shower on and off only when needed.5



There are systems that recirculate the hot water back to the heater but while these enable you to have instant hot water they promote heat loss from the pipes to the air.6



Other ways to save is through the use of instant hot water heaters (AKA tankless water heaters.) These don't have a tank and so save on storage costs but the cost to heat the water is higher. Savings may depend upon use.7



Finally there are point of use hot water heaters. These are typically small tanks to heat hot water near where it is going to be used. Savings will depend upon the layout of the building. If hot water has to travel a long way this might help. Some point of use heaters are also instant hot water heaters.8

Answer 4

I absolutely LOVE this question! With all the "Going Green" frenzy, no one has really taken a close look at where it counts..consumption. This question addresses a choice of energy/resource (gas/electricity/water) consumption at a most basic and personal level...shower or bath...

"..is there a system that can recirculate hot water until you are ready.." yes...its called a hot water heater! Unfortunately, there remains, as a commenter here stated, the initial cost of heating the water the first time THEN there's the added "cost" of "gray" water circulation/filtration equipment and energy used there of (search "eulo grey water sink"). With the increasing proliferation of on-demand "tank-less" hot water systems, any additional sub-processes i.e. collection, recirculation, filtration, reheating, etc. only adds price/cost even though you are seeking to be "efficient". The bottom line? Install a reduced flow shower head, and tank-less water heater, and or take fewer/shorter (efficient) showers/baths. THAT'S how you (everyone) will have the most impact in increasing consumer driven environmental sustainability.

Answer 5

Yes, a recirculating shower would be more efficient than today's showers, but it would be such a complex and unseemly system that few people would likely use it.



As for showers vs baths, a shower with a water regulator on the faucet, if used for a short amount of time, is much more efficient than a bath. However, if your shower pours out water like Niagara falls, and/or you take long showers, It would probably be better to use a bath.

Answer 6

There's an easy way to find out for yourself how much more efficient a shower is, which is to take a shower of a typical duration in the bathtub with the plug in, and see how full the bathtub is when you're done with the shower. I suspect that, in my case (mid-40's guy) the bath tub gets about 2 inches full from a shower, while when my 12-year-old tweenie daughter showers she probably fills it to about 8 inches! If you have a low flow shower head and keep your showers pretty short, you'll use way less hot water in the shower than in the bath.



When you take a bath, the heat stays in the bathtub, and in fact you can save energy during the heating season by leaving the bathwater in the bathtub until it is room temperature; it will give its heat up to the interior space of your home instead of to the public sewer system. That is one way to cut the relative energy use of a bath versus a shower.



Another thing to consider is a thermodrain, which replaces a section of your drain stack and helps recover heat from the drain water to feed back into the hot water tank. A thermodrain consists of a copper drain pipe surrounded by a coiled copper pipe that goes around and around the main pipe in a spiral. The water draining down the pipe (from your shower, sink, toilet, etc.) tends to cling to the outside of the pipe (it just does, trust me). Meanwhile, the water intake for the hot water heater is hooked up so that it runs from the bottom of the thermodrain to the top, going around and around the walls of the drain pipe. Of course the two channels (drain and water intake) are completely separate, but the heat transfers, and can significantly cut back on your hot water expense.



Your idea about recirculating the shower water is an interesting one but one problem I can see with it is that the water coming out the shower head starts to lose heat fairly quickly as it travels through the air. That's why the bathroom gets hot when you shower - because much of the heat is leaving the hot water. That's also why, if you do the experiment of plugging the bathtub while you shower to see how much water it uses, you'll find that the water around your feet is just lukewarm, not hot like the shower water was. As far as it being a viable product, I suspect another problem would be that most people wouldn't want to have 'gray' water coming out the shower head - water that's already got waste products in it such as soap, dead skin, dirt, and so on. They're perfectly happy bathing in gray water - bath water is implicitly gray, since as soon as they start stewing in it it becomes gray (kind of like a car loses 20% of its sticker value the moment you drive it off the car lot) - but people may find the concept of recycled shower water a little gross. Sticking some kind of filter on it might address that phobia.



The other approach to consider, in terms of conserving energy, is the on/off/on shower. This is what I do when it's not freezing cold in the bathroom - meaning, when I shower between about April and October. Get the water hot, wet myself, turn the water off, then lather and shampoo, then turn the water back on and rinse. I can be in and out of the shower in about 5 minutes with the water on for only one minute. Definitely not as luxuriant as standing in a hot shower for 30 minutes and not wasting energy, but probably easier to realize.

Answer 7

As you say it depends on how long is taken to shower, also the temperature of the water. A shower certainly uses less water than a bath.



Take a look at the following about recycling shower water http://www.treehugger.com/files/2008/04/quench-water-recycling-shower.php.



Shower water can be recycled as grey water, assuming you are green enough to use environmentally friendly soap!



Use solar power for heating the water will be more efficient.

Answer 8

Modern American baths usually require around 80 gallons of water to fill; a standard showerhead uses around 10-25 gallons for a typical 5 minute shower. Changing out your showerhead to a low-flow head and taking showers instead of baths can save a significant amount of water over a year's time.

Answer 9

Go in - ensure you're soaked all over then swich off the shower. The shower doesn't need to be running while you soap yourself. Switch shower back on to rinse and you've saved energy.



(Ever used one of those showers where you put your money in the meter and you get water for a limited time? You take enough to switch the shower on twice, right? )



ETA: Andrew - LMAO! It's not fit to drink but it's perfectly acceptable to flush the toilet and water your plants with!!!

Answer 10

this is incredibly basic to be sure. Take a shower interior the tub and placed the plunger in. except you're a veeery gradual showerer, purely a small area of the tub is crammed. And in case you employ a water saving bathe head even much less.

Answer 11

Yes! The amount of water to fill a tub 30cm, of hot water is a lot. then ,if you decide to exchange the water by adding more warm water, that's even more!



A shower, that uses 3 litres a minute, is going t save tons more water if your shower is only 15 minutes. That's at most 45 litres. An average tub can hold 50+ liters? And if you keep adding more water...

Answer 12

People need to have a shower or a bath,you can make the hot water last, and you have more water to rinse your body.Do not worry about showering and bathing, water can be used moderately and then when you get out of the bathroom just relax and be happy that you are clean.

Answer 13

Depends on the water used.



I've installed a lower flow head (I think it puts air into the water) and I turn it off whilst I lather up. I did a quick measure and I reckon my showers now use about 15 litres of water. A half hour power shower could use half a ton of water according to figures given here:

http://www.bchydro.com/guides_tips/green-your-home/water_guide/low_flow_shower.html

A bath is about a hundred litres on average iirc.



So yes, it depends on how long you take.







Someone even did an experiment at home!:

http://www.personal.psu.edu/cal5038/page%20four.htm

Answer 14

Hi there,



If you would like to have a really energy efficient shower then read the article below. (In particular item 4)





Andy Mahoney

Renewable Energy & Self Sufficiency

http://www.homebrewpower.co.uk

Answer 15

Yes, the navy way, but it requires discipline.

1. Turn on water.

2. Get in shower, wet body and hair.

3. Turn off water.

4. Soap/shampoo body and hair.

5. Turn on water.

6. Rinse.

7. Turn off water.



In addition in many municipal swimming baths the water supply is "pulsed", i.e. it turns itself off after so many seconds, you have to push the button again to get it back on.



Go here, the website is British but the same idea applies wherever you are.



http://www.trademarktaps.co.uk/product.asp?product=NCT003



EDIT: Do not mess around with Grey Water, it's horrible stuff, injurious to health. Don't even pour it down your toilet or pour it on your garden, get rid of it!

Answer 16

I'd have to say yes to that. For me, a shower uses half the amount of water that a bath uses. Not to mention, sitting in your own dirty water. Neh! I'll keep showering.

Answer 17

I think it's more a question of water usage really. You can get showers now that use less water. Plus .. how you're heating your water in the first place.

Answer 18

If it is a power shower then it uses just as much water as a bath.

Answer 19

After a bath don't you rinse off after with the shower?

Answer 20

yes b/c when u take the longest shower as u can it will steam up the bathroom and heat up ur house more

Answer 21

depends on how long it takes you to shower ,if you take a long time and pleasuring iurself maybe a little more unlesss its a quickie,but other than that quick shower vs bath maybe equal

Answer 22

showers use MUCH less water than baths.

Answer 23

i only keep it on to get wet and rinse. i turn it off when i soap up.

Answer 24

I'd have to say yes to that

Answer 25

anyone who worries about if a shower or bath is more expensive needs a REAL job.