I find it hard to adjust the water temperature to what I like. Is it because:
a) I have a very small range of preferred temperature, or
b) Most of the water temperature change occurs over a small adjustment?
If it’s (b), why does it do that? It seems easy to change the proportions of hot and cold water linearly with input, so I’m guessing there’s some effect where fast-flowing water blocks slower flowing?
I think it depends heavily on the specific faucet. The faucet we have in our house is one that has a separate knob for hot and cold, and even having the hot on a little too much will make any amount of cold water pointless.
Showers that have a “dial” type nob, that gradually changes from hot to cold, seem much easier to find the sweet spot in my experience.
I do admit that there seems to be a very small range of acceptable temperatures for comfortable showers though.
If you find it to be too hot, you can easily remedy the problem by lowering the themostat(s) on your water heater. Then you should be able to more easily dial-in a temperature in your comfort zone. The side benefit to this is that you’ll save a tiny bit on energy costs. A possible drawback is you’ll probably use a larger volume of your heater’s reserve of water, so if you have any problems with ever running out of hot water, this might not be a good idea.
I’m guessing you have a pressure mixing valve. Generally speaking the anti-scald features of lower quality products affect the range. Usually European equipment (Grohe, Hansgroghe, etc.) will give you a higher comfort range. Better still is to install a thermostatic valve.
The mixing valve is in the shower, it’s what links the hot and cold pipe before your showerhead.
I agree with drew that the comfortable temperature range is pretty small, a couple of degrees up or down feel very different.
Of course, we design bathroom valves with this fact in mind, so the average person can set a comfortable temperature without too much trouble. Before mucking around with valves, I’d say the best course is to lower the thermostat on your water heater
Don’t discount the fact that a lot of faucets just suck.
Our shower faucets vary a lot. A 5 degree turn of the hot is equivalent to a 180 degree turn for the cold. Also, there is a portion in the hot knob that makes it hotter when the knob is being turned down.
Also for our sink faucet (which is the all in one knob type), if you start from the hot side, and then center it, you will get hot water. If you turn the knob to the cold side, and then center it, you will get cold water.
At my parent’s house, the cold water knob does something really interesting. If you turn it on a bit, only a little cold water comes out. If you turn it a bit more, then LOTS of cold water comes out (like 5 times as much). If you turn it more, it will make a CLUNK sound and then only a little cold water comes out again. This makes showers always interesting.
The handle/ dial/ knob on the faucet can be constructed very different. Objectivly, the amount of temp. is not very big - I guess about 10 degrees C in either direction are quite a lot (I haven’t measured the temp of my shower water but I know that skin is very sensitive to small changes).
But you can easily translate a small difference to a big scale so that you need to turn the knob a lot to change just a bit. This would make it easy to find the right mix. Or you can make the knob small and fiddly so that a small turn means a (relativly) big change in temp.
Another aspect is the size of the hot water heater (and whether you’re sharing it with someone - in one Simpsons ep., Homer is upstairs under the shower, and Bart turns on the kitchen sink water faucet, causing Homer to yelp as the water temp suddenly changes. Bart naturally then starts to play a melody from Homer’s yelps…)
So at first, a certain position is “too cold” until the hot water arrives, then it’s “too hot” and you dial back, until the hot water is used up / somebody else cuts in, and it’s “too cold” again.
there is heat loss in the pipes, more if they are uninsulated (this is the most common). it takes a certain amount of hot water flow to be maintained for you to feel any heat in the water. small movements above that mixing point can take it to points of being too hot.
Run of the mill mixing valves depend on the user to adjust, and most of them are touchy. There are high end mixing valves that can be set for a particular temperature, and will hold it there for you. I had a friend who spent some $15K just on shower fixtures for his new home.
Add another vote for the faucets. I lived in my condo for 10 years with an impossible to adjust shower fixture. Turning the hot water handle to lower (less hot water) often made things hotter. How that works was explained to me once (maybe even here), but I don’t recall. In preparation to rent it, I replaced the fixture with a moderately priced one of those single handles, and it works great. Easy to hit the mark, easy to adjust when you want a bit more or less heat. Because I’m an idiot on such things, I only got to enjoy it for the last week I lived there, and I should have installed it the first week I moved in…
I stayed at a place in the UK with an in the shower “Power Shower” hot water heater. It worked great for providing on demand hot water, but it would get terrible lime deposits which restricted the flow, causing the water to get too hot even on the coolest setting. I don’t know if a whole house on-demand hot water heater can suffer from the same problem.
My logic is that I’ve noticed the same thing with my coffee. For quite a while, it is so hot that all I can do is sip it - and that’s what I like the best. Then for a short while, it is very hot, but no so much, and I’d better drink it fast, because very soon it is barely warm.
I do realize that the longer I’m drinking it, the more air mixes in to cool it. But it is still a relatively static system compared to adjusting the faucet. That’s why I think that our comfort ranges are truly much narrower than we realize.
I agree with this. Unless your shower only has two settings: 1) burn off 4 layers of skin, and 2) flash freeze to a cryogenic state (which many do) then it is the fact that we all have a very small sweet-spot that we like our shower temperature to be.
But maybe it isn’t cooling at a constant rate? There may be factors like evaporation, convection and warming of the cup.
I’ve thought of getting one that you can digitally program the temperature and it’ll handle the mixing for you, maybe even calculate how much time/water you have left based on your current hot water capacity. Can you get that for $15k?
But I’ve noticed it even after the hot water warms up. Unless there are hot and cold patches in the pipe, not just 1 cold then 1 hot patch? Also, can expansion of the hot water pipe cause a drop in water pressure?
This is what I’m wondering, does the flow of water or previous positions of the valve affect water flow? Maybe if you set it to 80/20, the flow of 80 will block the 20 so you get 90/10 instead.