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.
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.