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It’s crazy to me that American showers don’t use thermostatic mixing valves. It’s a better experience. The water gets to the temperature you want faster. It’s more stable. You set it once and it’s ready every time. It saves water because you don’t have to wait as long. It saves energy because you’re not heating up water you don’t use. It’s safer because it prevents scalding. And it’s — cheap. You can get one for like $30. We could finally solve the problem of every shower having its own confusing interface. The rest of the world uses these. Why aren’t we using them?

2:00 PM · Jun 20, 2025

438.5K

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Jesse Peltan

@JessePeltan

22h

It’s not 2008 anymore.

First post may not have been clear enough. You can change the temperature. It automatically adjusts the mix to maintain that temperature, so when somebody turns on a faucet or flushes a toilet the temperature doesn’t change. Thermostat gives you more control, not less.

Also. There is a difference between a *thermostatic* mixing valve, and a regular mixing valve.

At least we're not like the areas of Europe that haven't figured out you can have the hot water and cold water come out of and mix in the same faucet.

The hot water in my building has to go through 100-150(?) feet of pipes to get to my shower. I have to turn the shower on for a minute before it gets hot. Very, very dumb

Point of use heaters or circulation loops can fix this. Point of use should still be combined with a more efficient central heat pump.

In Omaha Ne its code to use them on any new installation. We have really strict plumbing code here though. The "it saves water because you don't have to wait as long" part is confusing me though. Unless you have a recirculation pump on the system. That does allow heat to be near

It’s roughly the same as turning on the hot completely and then adjusting it down once the hot water is flowing, but a savings relative to setting it to the position that normally works and waiting for it to get to temp.

In America each individual chooses their ideal shower temperature instead of learning to pretend to love the temperature that the household committee for public norms has decreed.

Quote

Jesse Peltan

@JessePeltan

17h

Replying to @JessePeltan

Americans don’t have this?

We’ve had it for 20+ years here

many such cases

I find three way valves to be deeply Communist and I cannot explain why

Is that supposed to be good or bad?

This is perhaps a dumb question, but I most often see these installed at the water heater. If so, how do you adjust the temperature at a sink or shower or whatever else that is downstream of the already-mixed water? My assumption is that these should be installed at every

At the water heater it allows you to keep the tank at a higher temp without the risk of scalding. (more heat capacity and better sanitation) At point of use it keeps a stable temperature by automatically changing the mix of hot and cold.

Nathan Odle

@mov_axbx

21h

Literally have one of those in my shower. They’re here just not common.

Yep! You can even get them on Amazon.

what if two people use the same shower and don't share temp preference?

You just set the dial and remember the temp you like it.

6.1K

sarah

@s4rah_dev

We install these (in Canada) but only in assisted living facilities. Main reason is they are kind of ugly and people don't want that.

126

Jesse Peltan

@JessePeltan

We need to make beautiful ones.

116

DadGolftheGray

@DadGolftheGray

The US would use thermostatic showers like Europe if they had settings for surface of the sun hot for our wives

104

Jesse Peltan

@JessePeltan

We do need an American version.

EagleTurd

@EagleTurd

23h

Can we get an image of what American's use? I thought its the same thing (mixes hot and cold).

Are there any barriers to installing this in the US? Cause it sounds like something everyone might want?

Not really. Just the knowledge they exist and how to swap one out.

3.5K

Mark of the Cyberbeast

@drmarkmancini

25m

Two words.... Cold plunge

I’m a fan

Sometime we want warm and sometimes cold. We like to control what we want at any given shower. Is this so hard to understand?

You can do that — better than one without a thermostat.

Is there anything to prevent you (or a plumber you hire) from installing these in your own home?

Nope! You can even buy one on Amazon and install it yourself!

We all like different temps.

You can change the temp. It just maintains whatever temp you set it to.

It’s the same with many US washing machines. They don’t have a thermostat to control the water temperature (something that has been standard in Europe for 30 years). US machines use the hot water pipe for Hot, the cold water pipe for Cold, and a mix for Warm. If the water in the

We definitely have those. We also have air conditioning, unlike most second world Europoors.

True

Most single knob faucets are built like that. They just dont look like that. Except for ones you have to reset in place to turn off you can leave them at the proper mix and turn on/off. Some have a single knob that just turns but also have a temperature ring on it somewhere.

Is that where I have one handle for pressure and another handle(single) for temperature? (Rather than hot and cold handles)

Yes, but it’s a little more than that. Instead of just mixing the hot and cold based on whatever pressure is supplied by each, it controls the mix to maintain the chosen temperature.

We don't use thermostatic mixing valves in Australia because of coal power. Off-peak hot water - either timer or ripple controlled - was introduced to give coal generation something to do in the wee hours of the morn & results in varying hot water temperature through the day.

This seems like a perfect use case for them.

507

@AwesomeAP

19h

This sounds like something the thermostatic mixing valve lobby would say

I’m a shill for Big Mix

Nothing is stopping you from installing this in America.

Yep!

I was just thinking about crazy it is that we all play this game of where exactly do I turn the handle to get the temperature I want

Steven Bower

@bowerblu

19h

Many such things US is behind on. Related: bidets. Everywhere else they are standard, even in relatively poor places in the middle of nowhere in Asia will have them. But in US they are extremely rare. Still don’t know why.

328

Grand Archon of Antimemetics

@im_in_a_vat

22h

to those who don't understand how this is different from most shower valves: in a thermostatic valve there is also a temperature sensitive spring mechanism that keeps the output temp the exact same by accounting for the temperature of the input cold and input hot water

550

@jik_wtf

23h

these max out at lukewarm anywhere I've seen them

One first simply needs to know that they exist. They are readily obtainable in the U.S.

Luke Riley

@misterluker

Didn’t know such a thing even existed.

Quinn Nelson

@SnazzyLabs

We do.

423

William Wallace Welker

@Will_W_Welker

19h

I use one. I heat my water with a wood boiler furnace outside. Temp gets up to 180 degrees. Mixer keeps it at 130. You can store more heat this way because less of your hot water is used for a shower.

357

Mike Sudyk

@sudyk

It’s not ready - still need to clear out the “hot” water in the line from the tank to the valve that has cooled

Eric

@CurlyRunnerEric

In the US you can pick up the Cash Acme "Tank booster" which is a kit to add a thermostatic mixing valve to any standard tank system so that you can overheat to have a larger effective capacity on your tank since it's mixed down from 140+f to a reasonable 120f.

Richard Sándor

@RichardSndor

12h

Americans use the imperial system, single-phase electricity, the MM/DD date format because of paper calendars, electrical plug designs that are 150 years old, and much more... Are you surprised? Hh

LOVtheCOV

@LOVtheCOV

14h

Pressure balancing and anti scald is built into every shower cartridge in the us. The most common cartridge iirc is the Delta 13/14 pressure balancing cartridge. Or it was when I was installing and fixing showers for thirty years.

That really makes sense, why not use thermostatic mixing valves, something safer, faster, cheaper and more efficient? .

@realDonaldTrump

@JDVance

and

@SecretaryTurner

, is it possible to help make this kind of upgrade standard in America? May God continue to bless, protect

Available in metric only

How does it reduce wait time vs common mixing valves?

I made sure to get an old school Moentrol for our old school bathroom. I don't know if it's thermostatic, but it has flow and temperature as separate controls.

Jeff

@tripplesixty

This is actually false. Showers have them internally, the mixing cartridge can be pre-set to your desired temperature and then when you turn to the on position it automatically hits your desired temperature.

I’m Fancy

@GarbageLiberty

22h

You are confused because most Americans USE thermostatic mixing valves. Almost all modern bath or showers use them. I have three installed in my home, as does almost anyone else with modern plumbing. I also have two gas powered tankless water heaters, which is a much bigger

474

TheFutureIsDesigned

@designed_future

Shown: Delta Thermostatic Valve, fits literally every Delta system (they designed it to be universal like that). Other brands also have thermostatic valves. I haven't seen a shower system without one for years already.

Lavoryn Nguyen

@lavorynnguyen

31m

Worked in Korea about 20 years ago and the hotel I lived in had this. I thought it was amazing. I’ve always wondered why we don’t have out in America.

yesnoerror

@yesnoerror

2 errors detected • Audit Score: 75/100

Someone used

@yesnoerror

to fact-check this post for errors with $YNE's AI agent. ---

ERRORS FLAGGED: • The claim that you can get a thermostatic mixing valve for $30 is misleading; typical residential TMVs in the US cost

The Dude Abides

@HermansenS15292

21m

Funny. I lived in Europe for 12 years with these. Upon returning to the US, I didn't have any sense this was a significant factor in quality of shower happiness, which I highly value. I'm the guy messing with flow regulators and water heater settings.

McCallum

@BK_McCallum

19h

Wait, you don't use those? Every shower in my house has one.

@albrecht_zack

19h

Thermostatic mixing valves do not reduce waste or improve heat response time because water in the pipes still must transfer through to the spout to a point it can deliver the requested heat. These only set the max temperature condition. The most cost-effective solution to

Yes, older buildings don’t typically use them - but I include thermostatic mixing valves from Delta and Kohler in all my bathroom projects. It’s already a standard installation when making or renovating bathrooms.

The only thing you don't seem to get often in the US is a calibrated valve with that obnoxious europoor lock at some lukewarm temperature. Beyond that they behave as you say, they maintain whatever temperature you set.

Berean Rogue Leader

@Michael824_

I installed one on my waterheater when I changed my entire system a year ago. It was a good choice in a house full of kids.

Kenneth "Mostly Skeptical" Davis

@daviskens

19h

Water is free with a well, and where does it get power? Need both a licensed plumber and a licensed electrician to install that $30 part.

Just put in a whole house one when I replaced our water heater. I have the heat pump tank heater maxed out at 150F, but the water that goes out to the house is capped at 120F. Helps avoid using the resistance backup heaters and stick with the heat pump.

bwooce

@bwooce

15h

Wait until your hear about the innovation that is a continuous hotwatee circulation loop. An idea that could only be invented in a land where energy was so cheap (I’ve only heard of it in America). Hot water with no latency.

Terry Losansky

@TerryLosansky

21h

My wife and I would find it difficult to agree on a single temperature. User detection required.

Moen, a US company, makes them. In fact, its hard to buy a non-thermostatic valve, which I wanted to do, because the thermostatic valves require a different screw arrangement, so I would have to take out the old pipe, and that's past my DIY skills.

I installed one on the tub shower that my kids use. Didn't get around to changing out the other ones.

Artur Urbanowicz

@ArturUrbanowicz

19h

Most new installations use mixing valves the only time a thermostatic is used is in daycares or retirement homes, to prevent burn injury

We do and I like the valves, but I will say it is not without a drawback. I have had to replace one (for a few hundred dollars in parts and labor) because our local water is pretty hard, and the set it and forget it led to mineral buildup that screwed up the valves and flow

Rep. Donald McFarlane

@donald4nh

We do use them. We just don’t mandate them.

Bang Stimuli

@RobHinged

Shocking how often we are screwed by our ‘Freedom’ Grok ### Conclusion There are no direct regulatory restrictions preventing TMVs from being engineered into U.S. faucets, but the lack of a national mandate, combined with existing code frameworks favoring pressure-balancing

FinSkirt

@FinSkirt

We do have these in the US and we use them in all areas of our house...not sure how you came to this conclusion but it appears to be off base. Can you clarify?

simply, seidoh

@gworley3

20h

never seen one with American units. chicken and egg?

145

Richard Bowman

@remax281

We have these in every hotel and hospital in America as part of code. Some apartments but residents have a choice and their choice is hot hot water not limited by a valve.

𝕏 Kid Plankton

@KidPlankton

18h

I just did a search on eBay for these, and they all come from either USA, Europe, or China. So, evidently they already do exist in America.

Scotty

@batteryscott

14h

"$30" "safer" There's nothing safe about these.

Engineering Randomness

@EERandomness

18h

What does it do when you run out of hot water?

Bill Buhler

@BillBuhler

So crazy question, does it allow hot to cold siphoning if the pressure drops on the cold side while the output is stopped?

Dr, Esquire, Revd Mal

@aimtomisb3hav3

There was a time I had a hot handle and a cold handle, and I chose which and how much I wanted by moving one or both. I liked those times.

Alec Dacyczyn

@AlecDacyczyn

16h

I just set my on-demand water to the temperature that I like and... that's it. My shower only has one knob.

Tony Guerich

@tguerich

13h

Ok. See that stuff labeled "hot water" ? How long until it arrives at the valve? If I don't run the cold water out ahead of it, it never arrives.

Andrew

@ApeWare

18h

38 is too cold for showering!

i put my tap in the same spot for 20 years. easy peasy

The Wasatchquatch

@waschatchsquach

15h

38 degrees! You must be freezing.

DogeMarine

@DogeMarineP

I have one on my hot water tank now, but I bypassed it becuase it needed to be replaced.

Chris Kelley

@ChrisKelleyX

I had no clue these existed Thanks for the advice

Yes and they suck

I have one of these in the house we bought and I absolutely love it but didn't know what it was called until now, thank you!

Blockchain Hedge

@BlockchainHedge

13h

Should I turn on my 2 large 3 ton a/c’s or just my backup Portable A/C ?

BT-7274

@Forged4Glory

17h

Older homes won’t have them, but now newer built houses do.

CoachChris11U

@11URingLord

17h

They are quite common here, actually. I don’t even understand the concept of running out of hot water anymore, either.

荒尽狩笑超

@Alex343

i have a tankless water heater. it works fine. the problem ive had was the previous owner built it into an enclosure which reduced airflow. i increased the airflow so it can breathe.

mrob

@mrobsmile

They are readily available and many do have them. Most large production home builders don’t install them because they are a couple bucks more than the other.

Curlyheads

@_curlyheads

21h

I asked me that in 1997 at my first visit to the US. Why would I want to use two knobs to mix my water temperature?

Wait, they‘re not?

I discovered this the hard way on my first trip to the US. I just assumed it would sustain the initial temperature while I was in the shower. But no.

Jordan Keto

@JordanKeto

19h

I’m an American my shower has one.

Ryan Loechner

@RyanLoechner

16h

“For like $30” .. and an em dash? AI much? I’m not hating on you for using ChatGPT, but FFS, edit it a little bit.

Son of a Doug

@MerelyLate

16m

I've never heard of those... but seems like a game changer

Shawn Clements

@ShawnCl28302661

19h

This takes longer to warm than just opening the hot valve all the way.

M B

@MB_energieinfo

I use a thermostatic electric flow heater (in German Durchlauferhitzer) with ~ 1m distance to the shower. 20 seconds to 34.5 °C. The 2nd parameter - flow - is regulated and can go down to 2l/min. 10-20l/shower with good experience is possible.