There are! They’re called thermostatic faucets.
this post was submitted on 20 Nov 2025
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I have a feeling like you could do a completely mechanical one. Like a way to push it open and a part gets pushed out to stay put so when you open the faucet back up it bumps it and has a little resistance when it first turns so you don't accidentally move it. Rotate the full way around to reset.
I'm amazed at the comments explaining incoming water temperature fluctuations and pressures....
No no, thermostatic tap/faucet mixes waters depending on the output temperature. Ignores all of the variables except the thermal mass (I guess reaction speed) of the thermostatic system.
I think they are normally like 10x the price of a standard mixer tap tho.
So, it's a budget choice
It's reasonably common for showers to have a mixing valve and a flow rate valve on separate handles. That accomplishes what you want. You just have to remember which is which and only use the flow rate valve to turn on and off.
More importantly, hot water circulation systems should be more common. It's the waiting for the cold water in the line to flush out that really makes setting temperature a hassle.
I thought a hot water circulator would be great, and it kind of is, but it comes with a drawback that I hadn’t considered. If you want cold water from the tap, to fill a glass of water at night for example, you have to wait for that just as long as you would have had to for the hot water before!
The solution to that is for a third return line to be run during a new build or remodel, but that's definitely not a weekend project for most homes.
My super basic faucet handles are exactly that…you twist it left-right to set temp and tilt it up-down for pressure from off to full. We just leave it rotated wherever we like it for temp and tilt up to turn on each time to the desired pressure. Our water pressure is always variable, so the amount tilted up varies, but the “rotational temp” almost never needs changing. There’s no fancy thermostatic valve in these like some shower have. There’s even those fancy kitchen sink faucets that remember everything and you just tap them with your hand and they automatically turn on/off to your settings of temp and pressure. I think they are called “touchless faucets”. Pretty sure even Ikea sells one.
I feel like sink handles like mine are super common, too. I’ve had similar ones in the states and in Europe…
My kitchen faucet does this. It's a 2-axis lever. Y axis is the temperature adjustment, X axis is flow. As long as you leave it set to the same Y position when you turn it off and on, it'll be at the "last used combination".
You mean a (single handle) mixer tap?
Keep in mind that mixing the levels of hot and cold water isn't the only factor in the final temperature. It's also the actual temperature of the water in the pipes. Depending on where your pipes run, the cold water in the pipes may be warmer or cooler than the underground source of the water. The hot water may also have cooled more or less since leaving your hot water heater. Initial temperature may therefore be too hot or cold compared to where it ends after a period of use.
I’ve seen these shower knobs before. They’re like a cold/hot lever plus a water pressure knob.
Something tells me water pressure variance might still throw it off day-to-day, though. It would be easier to control water temperature with an in-wall unit instead of central, so maybe something like that?
single handles are all well and good, but I'd prefer a hot knob, a cold knob, and a flow knob. I've never been clear why this isn't done, I suppose its probably cost. Maybe there is some wear and tare reason?
Seperate hot and cold knobs in showers are against code in a lot of places
Isn't this thread about sinks?
Ah shit, you're right. My brain just saw 'faucet'
Why would you need separate hot and cold knobs if all that matters is the ratio between them?
Because sometimes you want full cold, sometimes you want full hot. Yes you could use a three way valve but you'd generally lose maximum water pressure.
I don't understand how what you're suggesting could work any differently than a standard mixer tap, where if you want full cold you turn it the way to cold, and pull all the way to fully open. You say "you'd generally lose maximum water pressure" - how does the mechanism you're thinking of actually set the ratio of hot to cold, and how does it not lose pressure?
I'm so confused. What do the cold and hot knows even do?
they set the relative flow/pressure of respectively hot and cold water. The tap sets the total flow from minimum to maximum available based on the pressure supplied from.thenother two, allowing the selected hot/cold ratio to be preserved between on/off cycle, while also allowing for just a small stream of water when you need it, or a full flow of water when you need to fill a vessel or blast a dish.
People here saying single handle faucets must have much better ones than what we've got where I'm from, no fucking chance of getting the same temperature again after shutting it. And the middle of it is extremely sensitive, it goes from 10% to 90% in like the middle two millimeters, and I think the pressure of the hot water overcomes the cold's so you have to turn a bit left and then right again to stabilize the temp.
For my shower, which is the one that matters most for me, I got a thermostatic one—you set the temperature on the right handle and the flow on the left one, and that's it, perfect temperature forever. Even if someone flushes, which only happens when my sister is visiting because she doesn't understand boundaries, it doesn't change one whole degree for more than a second, only the flow is be affected.
As a side note my grandma's bath tube some 30+ years ago (it had probably another 30 or more) had two handles for hot-cold, left and right, and then another two for the shower-faucet flow, up and down. It wasn't as fine tuned as my modern one, but worked quite well. You would only open or shut without touching the proportion of hot/cold.
everytime
Not a word, my dude.
they will be ok in life