Having recently stayed in a hotel where the shower controls required the user to first pour cold water over themselves before it was possible to turn the control to the warm position:

I wondered what the perfect shower control interface would look like...?

  • Thanks for all the thoughtful answers - I'm stuggling to nominate a particular answer as the right one !
    – PhillipW
    Commented Oct 14, 2013 at 22:47
  • Have you considered that it was done that way on purpose? By forcing the user to wade through cold water if they stand in the way of the stream they remove the likelyhood of a user burning themselves. To use the shower properly you should stand outside the stream and wait. The hotel likely built it this way to reduce liability in lawsuits. Commented Feb 10, 2014 at 20:28

5 Answers 5


I think that the simple shower taps like this:
shower tap1 or this

work well using the following principles:

To operate:

  • Lift to increase flow
  • Lower to decrease flow
  • Left for hotter
  • Right for colder


  • You can adjust both flow and temperature with one hand, without looking at the tap
    (this not possible with either the two or the three tap systems)
  • You can shut down the flow, soap your self, then lift to resume the flow without changing its temperature
    (this is not possible with the two tap systems)

Possible changes that could be made above this:

a. Limit the maximum temperature to a temperature that won't burn your skin - safer and also enables opening tap at any angle without scolding skin without forcing user to turn tap towards cold first.

b. Limit the angle range according to the temperatures currently possible. (E.g. instead of 45 degrees left for max (safe) temp. to 45 degrees right for min temp., 30 degrees left to 45 degrees right if the water can't reach max temp. right now, or 45 degrees right to 30 degrees left, if the pipes are hot during the summer.) This enables user to always get the water flowing at an expected temperature, no matter what the actual limits are currently. This, however, does raise the following question: If the max. possible temperature goes down while you are showering, should the tap move to the current max. if currently beyond it - probably not, because then if a boiler kicks in and raises the max, your water wouldn't get warm again.

c. Alternatively to b, place a fast responding water temperature control to make the temperature match the angle you set it to even if the initial temperature is currently limited.

For reference:

2 tap system
image http://allgreen.com/site/images/stories/hot_cold_water_faucets

3 tap system
(source: americanstandard-us.com)

alternative flow and temperature control that requires two hands: image http://www.plumbnation.co.uk/site/roca-thesis-wall-mounted-thermostatic-shower-mixer-tap-1-2---5a1350c00-/shower-mixer.jpg

  • 3 handle faucets are no longer allowed to be built in new homes, from what I gather. The explanation I got was that they can not prevent super hot water like a single handle can. Old homes can get replacement 3 handle'rs but new homes must have the single. Commented Oct 7, 2013 at 4:20
  • 2
    @AthomSfere the regulations are location dependent. Commented Oct 7, 2013 at 5:11

I'd like to be able to set the water temperature in the same way I set my home heating and cooling temperature, by dialing it in and getting visual feedback. I picture something like the Nest thermostat which also remembers what temperature I prefer. After a few days of learning I'd only need to tap it to get it going. Then it would give me a Time-to-Temperature estimate that would tell me how long I should spend brushing my teeth while the water gets up to temperature.

Dial in your shower temperature

For a hotel, those memory settings would have a much shorter expected life. It would be no different from the bedside alarm clock that would need to be set uniquely for each room guest.

I am always scalding myself or freezing in hotel showers, because I invariably turn the dial in the wrong direction. Same way I often scan my debit card wrong because the diagrams indicating which way to position the card don't really work well in flatland.

  • How much is 72°F in Celsius? (Different people are used to different units.) Is 30°C cold or warm? (People aren't used to thinking about showers in degrees.) Presets could be nice, however, they'd need labeling according to user, e.g. A's warm shower, A's hair wash, B's warm shower, B's hot shower. Commented Oct 7, 2013 at 21:16
  • 72° F is 22° C. Given the user's preferred temperature scale, I think people could get used to setting their shower temp from the feedback of touching the flowing water, the way we do now with no visual reference of temp. People who swim outdoors quickly learn what different water temperatures feel like. 70° ocean water is a rare warm day in Southern California, where summer water temps are normally in the 60s F. I got used to thinking of water in degrees, and while it's not the norm, I think it is easily learnable, especially since this design learns and remembers your preferences. Commented Oct 8, 2013 at 13:42
  • That was a rhetoric question... I know how to use Google to convert units. Wouldn't want to have to do that during shower though, not even if I happened across such a shower while abroad :-) Commented Oct 8, 2013 at 19:41
  • I see now that you were channeling the perplexed international traveler and not asking me to google ;0 Commented Oct 8, 2013 at 22:20
  • 2
    I like the idea of being able to 'preset' my desired temperature at home.
    – PhillipW
    Commented Oct 14, 2013 at 22:41

enter image description here

In my opinion, whichever shower control you implemented you will still be under cold water first before adjusting to the comfort temperature due to the fact that you will still need to heat up the water.

A good indicator of the water temperature would be a better option to solve the problem of initial cold water. You can either use a digital indicator as suggested by Linda Brammer or using of color to indicate it. These shower head are already available in amazon and it's plug and play.

Edit: Even with the hot water boiling in the furnace, there will still be that momentary cold water that is between the furnace and the shower head.

  • a. In some homes and locations you can get got water instantly, especially during the summer. b. Most of the people I know do not like a cold start. c. Some people are color blind. d. If the bathroom light is bright, you won't see the shower colors and if it isn't, shaving in the shower will be more challenging. Commented Oct 7, 2013 at 5:16
  • 1
    e. The order of colors you gave as an example isn't a natural order. While red usually symbolizes hot and blue cold, the other colors have no temperature context and the natural order of colors, using blue as start point due to it's connotation with cold, as far as the human eyesight perceives them is blue, green, yellow, orange, red, purple. Or if you prefer red as max, then purple should be before blue. Commented Oct 7, 2013 at 5:22
  • a. Even with the hot water boiling in the furnace, there will still be that momentary cold water that is between the furnace and the shower head. b. true, but it's inevitable. c. I am one of them. d. the shower head is the one lit up, not the water but I get your point. e. Can't agreed more, unfortunately I'm not the one who designed this. I just grab it off the net.
    – SimonTeo
    Commented Oct 7, 2013 at 6:05

First of all, we need to realize what the constraints are. The desired temperature of water does not equal of the temperature of water that is:

  • in the trunk (is it even a right word? well, I mean the tube between the faucet and water outlet)
  • and also probably a part of the pipe.

It is (theoretically and technically) possible to keep it at some predefined level, perhaps, but the cost of maintaining the proper temperature would be high (constant warming up to some system preset e.g. the temperature of the body). So from the economical point of view you need a workaround.

There are few ways yo can go, either choosing some of these or all (most of these have been already proposed in the other answers):

  • giving user possibility to pour out water of incorrect temperature before s/he steps into the shower cabin. In case of tube/shower combos there is a possibility to direct water either to the shower or to the faucet, so that you can use the latter and then switch to the first one.
  • giving visual cues explaining the (obvious) fact that the water temperature may be not at the desired level from the beginning
  • giving user possibility to adjust the water temperature - either by predefining it at some level or by trial and error, checking the temperature and then changing the setting
  • giving visual feedback about the temperature - the LED pattern shown by @SimonTeo is great here.

My idea how to deal with it is a control which: * allows user to preset temperature (but how to tell him that a preset on a control equals some temperature? You can go Celsius or Farenheit or some more descriptive way - "temperature of body", "warm shower", "cold shower") * then, until the water does not reach this temperature, water is directed to the drain - this point would need to come with a visual feedback of it that users would understand (a pulsating led or something saying "wait for the water"), otherwise userw would just think the shower does not work at all * once the temperature reaches the preset, water is directed to the shower

But still, the amount of water that stays in trunk is a problem - it is behind any control unless it is sucked out of the trunk, so that only water of the desired temperature reaches user's body.


This question assumes that the design of the shower knob is at fault. It is important to define the problem, list the requirements, and allow the engineers to provide the solution for your specific problem.

The looks of the "perfect shower control interface", is completely opinion based and has no bearing on the problem defined.

shower controls required the user to first pour cold water over themselves before it was possible to turn the control to the warm position

The main obstacle here, is that hot water is seldom available at the tap (it has been cooling since the last running). There are two paths to solution.

  1. Place the shower control in a position where it can be adjusted without entering the shower spray.

  2. Design the plumbing and valves to allow warm water to constantly be available at the the tap at all time.

The first solution is employed in the majority of standard installations.

The second solution uses a return line to the hot water tank, it keeps hot water flowing to the faucet at all times. There are cost benefit options to consider, that can be taken up with your local utility company and plumber.

In either case,

the perfect shower control interface would look like

What every you would like it to look like, the solution to getting drenched with cold water in the shower is mechanical, and has no impact on aesthetics

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