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Pressure Balance Vs. Thermostatic Shower Valves

Learn the difference between pressure balance and thermostatic shower valves.

Getting clean is an important part of our daily routines but it can be difficult to find the time or space for a bath. Showering is now the most popular way to stay clean, with about two-thirds of Americans taking a shower daily (1).

If you are buying a new shower, you will have plenty of options, including pressure balance and thermostatic valves. With so many different showers to choose from, you might need some more information about how each type works.

To help you make the right choice, this article will explain pressure balance vs thermostatic shower valves. This includes how each type regulates water flow and temperature, their ease of use, and their durability.

Key Takeaways

  • Pressure balance valves control water temperature by regulating the hot and cold water ratio, while thermostatic valves directly adjust the water temperature.
  • Thermostatic valves maintain a consistent temperature and offer greater control, but are more expensive and complex to repair.
  • Pressure balance valves are more basic, easier to operate, and less expensive, but can fluctuate in temperature when other water sources are used in the home.
  • Thermostatic valves are worth the investment for increased comfort, safety, and energy efficiency, especially in homes with vulnerable individuals.

What Does a Shower Valve Do?

A shower valve has two main functions: controlling the temperature of the water that comes from your showerhead and regulating how quickly it flows out.

Depending on the type of valve, it does this by either mixing hot and cold water to reach a specific temperature or by heating cold water as it flows through the unit.

How Does a Shower Valve Work?

There are two main types of shower valves: pressure balance valves and thermostatic valves.

Pressure Balance Shower Valves

Product Image of the Grohe 35204000 In-Line Remote Pressure Balance Valve

A pressure balance shower valve usually has one handle that controls both the temperature and flow rate of the water. The pressure is balanced by either a sliding disc on a piston or a spool that controls the water ratio.

With this type of valve, there might be temperature fluctuations when someone flushes a toilet or runs a tap elsewhere in your home. Pressure balance valves are better at controlling water pressure than regulating temperature.

They also generally deliver moderate heat but might struggle to give you a steaming hot shower.


  • Lower initial cost
  • Scald protection
  • Comfortable temperatures


  • Takes time to achieve the specified temperature
  • No temperature memory
  • No additional scald prevention
  • No bacterial protection

Thermostatic Shower Valves

Product Image of the Moen Brass Posi-Temp Pressure Balancing Tub and Shower Valve, Four Port Cycle Valve with Standard 1/2-Inch IPS Connections, 2510

Thermostatic valves have two handles. One controls the pressure of the water and the other regulates the temperature. These valves react to the water temperature and not the flow. Inside the valve, a wax element expands and retracts in response to how hot or cold the water is. This helps it maintain a constant temperature even if there are fluctuations in the water supply.

A thermostatic valve should deliver the right water temperature every time and give you the ability to set and forget. However, they are more expensive and, when they malfunction, they can be more complicated to repair.


  • Consistent temperature
  • Energy-efficient
  • Sets precise temperatures
  • Higher flow rates
  • Bacterial protection


  • More expensive
  • Complicated to repair

Pressure Balance Vs. Thermostatic Shower Valves

The main difference between the two types of shower valves is that pressure balance valves control the ratio of hot and cold water to regulate the temperature, whereas thermostatic valves control the temperature of the water itself.

There are some other significant differences between the two types of valves. Thermostatic valves provide greater control over the temperature while ensuring a steady flow of water. You can set a thermostatic valve and be confident that it will deliver the same temperature the next time you step into the shower.

A pressure balance valve lacks these luxuries. You are also at the mercy of other people in your home, as flushing a toilet or washing their hands could mean you receive a sudden blast of hot or cold water.

Pressure balance valves are more basic so they are heavily affected by fluctuations elsewhere in your home’s plumbing system.

Pressure balance valves are easier to operate than their thermostatic counterparts because they only have one handle. This makes them a good option if there are any vulnerable users in your home and you want to protect them from extreme temperatures.

To give you a clearer picture of the differences between the two shower valve types, we put together this handy chart:

Features Pressure Balance Valve Thermostatic Valve
Cost $ $$$
Temperature set X
Water flow Good Good/Excellent
Water flow control X
Ease of use Easy Medium
Bacterial protection X
Service life 10+ years 5 years
Scald protection


How Do You Adjust a Thermostatic Shower Valve?

To adjust a thermostatic shower valve, you will first need to remove the cap to reveal the adjusting spindle. Use a screwdriver or another thin object such as the tip of a butter knife to turn the adjusting spindle. Turn it clockwise to reduce the water temperature or counterclockwise to increase it. Once you have reached the desired temperature, pop the cap back on.

How Do You Fix a Thermostatic Shower Valve?

The easiest way to fix a thermostatic mixing valve is to reverse the valve by attaching the hot to the cold. Then, pop the cap off the adjusting spindle and find the right temperature setting for the hot water. For more complex issues, you will probably need to call in a plumber for assistance.

How Long Should a Thermostatic Shower Valve Last?

There is no universal answer to how long a thermostatic shower valve should last as it will depend on how frequently it is used and your local water quality. Hard water usually has a detrimental effect on plumbing fixtures compared to regions with soft water. This is due to the water’s mineral content causing limescale deposits, which make pipes narrower and force your shower to work harder.

You will probably get 3 to 5 years of use from a shower valve in a hard water area, but you should get double this in a soft water location, or possibly even more.

How Do You Clean a Thermostatic Shower Valve?

To clean a thermostatic shower valve, remove its thermo cartridge and place it in a bowl containing a mix of equal parts warm water and white vinegar. Leave it to soak for 10 to 15 minutes and then gently remove any stubborn stains and limescale with an old toothbrush.

You should also flush the shower openings at this point to remove any limescale left in the pipes. Then, place the cartridge back into the valve and turn on the shower to test that it is working properly.

Take Note

This method only has about a 50% chance of working. If you notice that your valve still isn’t working properly after trying it, you will probably need a professional repair or a new valve.

Are Thermostatic Shower Valves Worth It?

Thermostatic shower valves are more expensive than pressure balance valves but they are an excellent investment if you can afford one, providing greater comfort and safety. These valves prevent sudden temperature spikes and maintain the set temperature even if other water outlets or appliances are used while you are in the shower.

This is especially important in homes with very young or old people who might be more vulnerable to scalding. By ensuring consistent temperatures, these valves can also save energy, which could help you reduce your bills.

Are All Shower Valves Pressure Balanced?

Not all shower valves are pressure balanced. Pressure balance is a feature available on some shower valves that utilize a diaphragm and calibrated spring to balance the water pressure and temperature between the hot and cold supplies.

This helps maintain your chosen heat, even when other water outlets or appliances are used in your home, so sudden changes in temperature should be less of an issue.

A pressure-balanced valve will be worth it if you want safe, comfortable showers as regularly as possible.

Do Thermostatic Shower Valves Fail?

Thermostatic shower valves are generally very reliable. However, like any plumbing component, they will eventually fail due to years of wear and tear or debris build-up. It is important to check your shower valves regularly for signs of damage or corrosion, as these will eventually lead to the valve no longer working.

If you notice sudden temperature spikes or water leaking from the valve, you should call a plumber for professional assistance. If a leak is coming from the valve itself rather than its connections, it could be a sign of too much wear and tear and you might need to start looking for a new one.

Taking proper care of your thermostatic shower valve will reduce the risk of it failing and ensure you get as much use out of it as possible.

Do Pressure Balance Valves Control Volume?

Pressure balance valves are designed to regulate water pressure, not volume. Even so, most pressure balance valves have a built-in control that adjusts the flow rate of water from the valve.

This means you should be able to adjust your valve to achieve the right flow rate for a comfortable, cleansing shower.

Are Thermostatic Showers Valves Better?

Thermostatic shower valves have definite advantages over standard older models as they provide precise temperature control and are far more efficient.

They have a built-in feature that detects any sudden temperature changes in the water supply, so you won’t suffer any scalding or bursts of cold water. They also enable you to easily adjust the flow rate separately, so you will have much more control over your shower.

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About the Author

Mark Weir

Mark spent 24 years working in real estate, so he knows his way around a home. He also worked with contractors and experts, advising them on issues of planning, investments, and renovations. Mark is no stranger to hands-on experience, having renovated his own home and many properties for resale. He likes nothing better than seeing a project through to completion.