There's a clever product that you can screw inline with the showerhead that lets cold water through at full blast but when the water gets hot, something pops (presumably using metal-expansion properties the way old thermostats did) and the flow is reduced to a trickle, so you only use just enough water to keep it hot.
Then when you get in, you pull a cord and it releases the full pressure of nice hot water.
We just keep a 5 gallon bucket next to the shower and fill it up with the pre-warm water. Then we use it to water the garden (and sometimes to power flush a stuck toilet).
The Pakistani method: shower with fully cold water in the summer. And mock anyone (mostly spoiled people from the Middle East) who turns the water heater on during summer months.
Related: you can buy "hot water recirculation systems" to keep the water hot in your shower. When the water in your hot water pipes gets cold, it dumps it into your cold water pipes. Therefore the water isn't wasted.
This can save a lot of water if you're the type to let your shower run until it is warm. So some jurisdictions encourage their installation.
"Far more" is relative, to say the least. We're talking about the amount of water that fills a shower pipe - very little - and unless you're only showering once a week it's not that big of a change.
In our house, the master bath is on the complete opposite side of the house from the water heater, and we have to run about two gallons of water before it gets hot, and if we wait more than 10 or 15 minutes between showers, the water in the pipes gets cold again, and we have to run another two gallons. In other words it isn't just the water in the shower pipe, it is the water in the full pipe between the heater and the shower.
I've just started looking into either getting a tank-less water heater in the master bathroom or a recirculating system to save water. I like that the recirculating system would help with the entire house, not just that one bathroom, but it is looking to be quite expensive and wasteful of energy, unless we can do something like have switches in the bathrooms and kitchen to manually turn on the recirculator for a few minutes before use instead of running the water for a few minutes.
Look at instant hot water heaters to colocate near the fixtures; they don’t have to be powerful enough to provide hot water for the entire fixture use, just the time between when fixture use starts and hot water arrives from the primary heat appliance.
Fossil gas tankless units are nice because they can be installed on the exterior of a home and are maintenance free, but emit CO2 and can be expensive depending on your gas costs (they’re better for seasonal dwellings imho). Ideal combination is resistive instant heaters at points of use with a heat pump water heater for the whole dwelling.
They don't have to be instant either: I've seen 120V plugin models that have a small tank. No idea what's better, but you don't need a 240V hookup in the bathroom to have a "while the pipes heat up" heat source.
In my house it's a lot. Due to the shower being in a different spot than when the house was originally built so the routing is about as inefficient as possible, there's well over 100 feet of pipe between our hot water tank and our shower.
How much time does it take? In the US almost all shower-heads and faucets will only use a maximum of 2.5 gallons per minute. For me the water will get hot in about 30 seconds. So I am using approximately 1.25 gallons of water. For me that is acceptable.
You probably wouldn't need it in a single-family dwelling, but there's a recirculation system in my 100+ unit building and it works great. Once it was turned off by accident and it took almost a minute to get hot water. Multiply that by all the neighbors and it seems like a good bargain.
Like all thing in the water-energy nexus, the right answer depends on whether you live in a water-stressed environment. In California this may be a great idea, but it is probably not useful in New York.
There is no water shortage, there is an energy shortage. You can easily desalinate as much water as you want, it costs about $0.002 per gallon, while heating a gallon of water is 10x that.
Desal is 3.8 kilowatt-hours per thousand gallons while heating water 70 F to 120 F (reasonable minimum range) is 122 kWh per thousand gallons. You're absolutely right, this is a case where it makes no sense to use energy to save water.
Probably depends on your heater setup. My parents have a flow-activated central heating system in the basement and waiting for warm water can take over a minute. In my current apartment, I have an electric heater basically next to the shower and the water is warm within a few seconds at most.
I don't know if they are still around, but I've seen a shower head that includes a clever mechanism to reduce water waste if you let the shower run until warm.
When you turn on the shower, the head operates normally while the water is cold. When the water becomes warm a valve in the head closes to stop the flow. There is a button on the head you press to open the valve, which then stays open until you turn off the water.
The idea is that many people turn on the shower to warm up but don't just wait around in the bathroom to jump in as soon as the water is warm. They go do other things like start their coffee machine or wake up the kids or check the news and weather. Between the time the shower warms up and they get around to coming to see if it is warm they might waster several minutes worth of warm water.
With this clever shower head they don't waste that water. Also, if they can hear the shower running from wherever they are doing other stuff when they hear it stop they know the warm water is ready.
I get in, turn the water on max hot, and stick my hand in the stream of water coming out of the tub spigot. As it gets hotter, I adjust the temperature setting and converge on the right place. Then, I hit the diverter so water comes out of the shower head, while I stand mostly out of the spray (avoiding residual cold water and it takes a few seconds to warm up the pipes themselves). Then I stand fully under the spray and do minor adjustments, which continue throughout the shower.
This seems natural to me, but I've never met anyone else who does it this way.
I think it really depends on your water system at home. In this apartment, the water heats up fast and gets really, really hot. So it takes about 5 seconds to reach the desired setting. There’s also a pretty good range where it feels good to get in. So it’s just not worth putting a lot of thought into it.
At other apartments, I’ve had more involved systems.
This thread is making me think of that blog title: Reality has a surprising amount of detail.
I didn't spend any time designing that set of steps or anything. Rather at each point I'm just doing the immediate thing that will get me showering the quickest.
It's probably most useful when the hot water comes up quick, less useful when you have to wait a while for that. And it fails horribly when the hot water isn't working.
I've never felt the need to adjust though, except for shower-only stalls and the like.
I think those mostly work when the shower is running though. When it's stopped the water in the cold pipe is eventually going to get cold. Still a good idea - I've been planning to get one when I next redo my bathroom.
These work when the hot water is cold, about twice a day for me, less if the shower is used regularly. The valve opens and water flows from your hot water pipe into your cold water pipe.
So you should turn it off when you go on vacation.
What's "a lot of water" in this context? My shower typically takes just a few seconds to get to temperature. Even a quick shower is typically a few minutes, so that tiny amount seems insignificant.
Why do not people use a bucket and a mug. By collecting water from the shower from freezing cold to scalding hot you average out the temperature for a nice warm shower and no wastage.
It seems like a no brainer, but the prices are so high (like £700 / $900) that it would take many many years to pay back the cost, so it wasn't worth it.
Not quite as effective, but even easier is that you can get a back-flow preventer valve (approximately $10 worth of metal) that allows the hot water to push into your cold water (but not the reverse)
As I understand it (and I am NOT a plumber) -- when you turn on the hot water, it pushes hot water up the line. Turn off the water, and that water will cool. But, if you add a one-way valve that allows flow from hot to cold, it will allow the higher pressure hot water line to flow into the cold water line so that it keeps hot water to the tap so that you don't have to wait (in my case) 5 minutes to flush out the cold water that has accumulated before getting to the hot water.
A plumber friend suggested this to me when I complained about my master bathroom (the furthest in the house away from the heater) taking SO LONG to warm up. Then he came out and installed it in about 15 minutes (which would probably amount to a one hour minimum charge for a plumber not doing it for free) plus a $10 part he had us buy on Amazon.
TLDR, now instead of taking 5 minutes to heat up from ice cold to warm to eventually hot, the hot water is warm from the second I open it, and hot within about 15-20 seconds.
If you have a sink near the shower, run it full blast on hot to flush the cold water from the pipe.
This mainly saves time, but it also saves water if your shower mixer valve doesn't go to 100% hot. (It's generally good to keep the hot limiter below 100%, to avoid full-body scalding.)
I think that blast of cold water might have done good things for his endorphin levels. Just curious about this anecdote, was he generally a happy person?
for me, I take showers at night close to bed time. The last thing I want to experience is a cold shock to my system at that time of day. I can see it being useful in the morning though
That ... still seems like the wrong way. Every shower I've known has let you angle the head down. So start it that way, feel for the water to get warm, then turn it towards you.
With the method you described, it takes longer, with more water usage, to get into position, plus you let some water spray out into the rest of the bathroom as you transition inside it.
I start with full cold because it's more of a shock to the system. I find the cold water improves my mood and provides a daily dose of "suck it up, buttercup". I've __almost__ started crave that cold shock in the mornings now, and the cold water at the end of the hot shower feels like .. relief.
> The best part of having cold showers every day? You'll never get arthritis!
Is that so? My joints in fingers and toes can hurt quite badly after being to too much cold water. Doesn't feel like it's helping them in any way - quite the opposite.
my shower at my current apartment actually have the temp and volume nozzles separate so that i can taper the water pressure and it stays hot. Its delightful, i dont know why this isnt standard.
Me: "Why don't you turn on the shower, wait for it to get warm, then get in?"
Him, realizing he'd been using a shower wrong for over 6 decades: "... huh."