Why Is It So Difficult to Get My Shower Temperature JUST Right?

Why Is It So Difficult to Get My Shower Temperature JUST Right?

Dealing with a “fussy” shower faucet is a bad way to start your day.

One touch to the right and you’re blasted with cold water. One tap to the left and scalding hot water has you hugging the shower wall.

The problem could just be an old, faulty shower lever, in which case you should try replacing it.

But if you have a relatively new faucet, take a quick look at your shower set up. Is there a single-control lever?

If so, it most likely uses a pressure-balancing mixing valve, which could be the culprit.

The solution? Switch to a thermostatic mixing valve.

We’ll discuss the differences between the two and why switching to a thermostatic mixing valve gives you better control over your shower temperature.

Single-control levers=less temperature control

If your shower has a single-control lever, you most likely have a pressure-balancing mixing valve.

So what is a mixing valve?

A mixing valve is installed into your shower faucet and blends hot and cold water together to deliver comfortable showering temperatures.


A behind-the-scenes look at your shower mixing valve.
Photo source: Houzz

But when it comes to a pressure-balancing mixing valve, there is a major setback in the way it adjusts your water temperature.

Here’s the thing: 

Pressure-balancing valves don’t directly control the temperature of your shower water. In fact, they can’t even sense temperature. Think of them as simply adjusting the ratio of cold to hot water pressure.

For example, in the picture below, the movement of the lever simply changes the ratio of hot to cold water. There is no measurement of temperature, just a mechanical balancing act of hot water mixed with cold water.


Photo source: Bradleycorp.com

Basically, the hot water coming out of your showerhead has the potential to get as hot as the water stored in your water heater if the lever is pushed as far left as possible.

And that makes for dangerous scalding temperatures. But it also creates a huge temperature range for you to navigate and makes it difficult to find the “perfect” shower temperature.

While pressure-balancing valves can set a maximum temperature limit, this is basically just a mechanical “stopper” that stops your lever from rotating at a certain point.

So if you have a single-control lever, your morning shower routine likely starts with a time-consuming, lever-fidgeting guessing game to find a comfortable ratio of cold to hot water.

Tired of playing the guessing game? Try switching to a thermostatic mixing valve.

Benefits of a thermostatic mixing valve

Thermostatic mixing valves typically offer two handles: one to control the water flow (pressure) of water and one to control the water temperature.


Photo source: Signature Hardware

This valve works similarly to a pressure-balancing valve in that it blends hot and cold water but it actually senses the temperature of the water and controls it directly for more precise shower temperatures.

There are various ways a thermostatic mixing valve sense temperature.

Some have a wax insert that contracts and expands in response to the water temperatures. Other more modern valves have thermostats that read and respond to temperatures.

Thermostatic valves make it easy to find and maintain the perfect shower temperature.

Because you have a faucet dedicated to just water temperature, you can find the “sweet spot” and leave the lever in this position from shower to shower. Just adjust the water flow lever and voila: the perfect shower temperature, every time.

Other benefits of a thermostatic valve include:

  • Safer temperatures. Thermostatic mixing valves can be pre-set internally to your desired maximum temperature. For example, if your water heater produces water that is 140 degrees F, you can set your shower temperature to never hit above 105 degrees F. This keeps you and other guests safe from scalding temperatures.
  • Complete control over water flow. With a control dedicated to water flow, you can increase or decrease the flow of water easily. Want to conserve water while you soap up? Just turn the lever to lower the volume of water in your shower and turn it back up when you’re ready to rinse off.
  • No drop in water pressure. Unlike a pressure-balancing valve, thermostatic mixing valves prevent drops in water pressure when other water-using appliances are in use.

Note: The one drawback of a thermostatic mixing valve is price. They are more expensive than pressure-balancing valves because they offer more advanced features.

Still interested in upgrading your showering experience but not up for the hassle of a DIY shower valve replacement?

No problem.

Contact Mr Plumber today for a reliable Atlanta plumber who can replace your shower valve safely and quickly.

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2017-08-01T14:33:59+00:00 July 19th, 2016|Help & Tips, Homeowner Tips, Plumbing|