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Pressure Balance Vs. Thermostatic Shower Valves

Learn the difference between pressure balance and thermostatic shower valves.

We all need to be hygienic, but we rarely have the luxury of time to languish in a bath. A shower is the answer. 66 percent of Americans shower every day (1).

This article looks at the merits of pressure balance shower valves and thermostatic shower valves to determine which one is the best. Join us as we take a closer look.

Pressure Balance Valves and Thermostatic Valves

Pressure balance valves are excellent at regulating the flow of water and the ration of hot water to cold. This is how they produce a comfortable temperature. Thermostatic valves take direct control of the water temperature, heating the water to the desired setting. They do not have control over the flow of the water.

What Does a Shower Valve Do?

A shower valve has two primary functions, namely, to control the water temperature that comes out of your showerhead and to control the flow of the water.

It controls the heat by taking hot and cold water from your supply and mixing the two in different proportions.

How Does a Shower Valve Work?

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

Pressure Balance Shower Valves

Product Image of the In-Line Remote Pressure Balance Valve

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

With this type of valve, you get temperature fluctuations when someone flushes the toilet or runs a tap elsewhere in the house. Pressure balance valves are better at controlling the water pressure than they are at regulating the temperature.

They also deliver a moderate heat rather than a steaming hot shower.


  • Lower initial cost.
  • Scald protection.
  • Moderate comfort.


  • Takes time to achieve desired results.
  • 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 the temperature. These valves react to the water temperature and not the flow. Inside the valve, a wax element expands and retracts as it responds to the water’s temperature. This helps to maintain a constant heat to reduce fluctuations.

Thermostatic valves deliver a hot shower 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.
  • Accurate.
  • Set exact temperature.
  • Higher flow rates.
  • Bacterial protection.


  • More expensive.

Pressure Balance Vs. Thermostatic Shower Valves

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

There are some other significant differences between the two types of valves. Thermostatic valves give the user more control over the temperature while creating a steady flow of water. You can set a thermostatic valve and know that each time you step in the shower, it will deliver the exact temperature you want every time.

With a pressure balance valve, none of these luxuries exist. You are also left vulnerable to other people in your home affecting the quality of your shower by flushing a toilet or washing their hands.

Pressure balance valves can’t cope with many tasks at the same time, because the pressure of the water in the system inside your home fluctuates with heavy usage.

Pressure balance valves are easier to operate than their thermostatic counterparts because they only have one handle. This makes them the ideal choice if you have elderly parents or young children and want to protect them with moderate temperatures.

To highlight the difference between the two types of valve, we thought we’d produce a 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
Scalding protection


How Do You Adjust a Thermostatic Shower Valve?

First, remove the cap to reveal the adjusting spindle. Using a screwdriver or something thin like the tip of a cutlery knife, turn the adjusting spindle clockwise to reduce the temperature of the water, or counterclockwise to increase the temperature.

When you have reached the desired setting, 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.

How Long Should a Thermostatic Shower Valve Last?

The answer to this question depends on the frequency of showering and the quality of the water in your area. Hard water areas tend to punish plumbing fixtures much more than soft water locations. Limescale can build and cause valves to reduce in efficiency.

You will probably get 3 to 5 years service in a hard water area, but in a soft water location, this number could double to 10 years.

How Do You Clean a Thermostatic Shower Valve?

Remove the thermo cartridge and soak it in a bowl using a 50/50 mix of warm water and vinegar. Leave it to soak for 10 to 15 minutes and then gently remove any stubborn stains and limescale with a toothbrush.

It would be a good idea to flush the shower openings at this stage to remove any limescale in the pipes.

Now replace the cartridge and turn the shower on to test the water.

Please Note

This method only has a 50 percent chance of working. If your valve still doesn’t perform, you probably need a new valve.

No More Cold Showers

No one likes taking cold showers unless it is the height of summer, and you want to cool down. There is nothing quite like the feeling of warm water covering you from head to toe.

Keeping your shower in good working order is a priority, especially if you don’t want your friends and relatives to smell you before you arrive.

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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.