A Shower Valve is the brain behind your shower wall. It turns your showerhead & faucets on & off and regulates the temperature. To many people, it is the most confusing element of their bathroom. Fortunately, we decided to make this simple guide to help you understand what they are, how they work, and how to configure them based on your needs.
There are 3 types of shower valves
- The Hot & Cold Valve
- The Pressure Balanced Shower Valve
- The Thermostatic Shower Valve
Each valve is a technological advancement over the previous type. The pressure balance valves has virtually replaced all traditional hot & cold valves, while the thermostatic shower valve is considered a luxury upgrade over the pressure balancing valves.
Traditional Hot & Cold Shower Valves
The Hot & Cold Handle Valve
A traditional hot & cold shower valve is a type of shower valve that has been around for many years. It is simple, consisting of only a few parts: a hot water inlet, a cold water inlet a mixing valve & a water outlet. The mixing valve combines hot and cold water to the desired temperature and sends it to the showerhead and faucet.
Handle Trim for Hot & Cold Valve
The traditional valve operates like your standard two handle faucet. Unlike other types of valves, its valve trims come equipped with two separate handles. You simply turn the left handles for hot water and the right handle for cold. As you turn on the water, you will increase the volume of each side to your desired temperature.
One important thing to note is that the traditional hot and cold valve has no anti-scald feature. This means that there is no built in mechanism to ensure that the water doesn’t get too hot if there is a sudden loss of cold water.
As a result, the traditional valve is seldom used today and has become somewhat of a dinosaur.
Pressure Balancing Shower Valves
Pressure Balance Rough-in Valve
A pressure balance shower valve is a type of fixture that mixes hot and cold water to provide a consistent temperature to your shower. Like the traditional valve, it uses the volume ratio of hot to cold water to regulate flow and temperature. However, it has the added benefit of being anti scald.
The unique component of the pressure balance valve is the pressure balancing spool. This part helps prevent scalding by detecting the sudden drop in water pressure on the cold side and in turn reduces the hot water to prevent a sudden burst of scalding water.
These sudden drops occur when someone uses another fixture in the house that requires a lot of cold water in a short amount of time. The most common example is when someone flushes the water while you’re taking a shower. If your shower has a pressure balance valve, you will not be scalded but you may experience a sudden drop in water pressure and slight hike in temperature.
Standard Shower Trim for Pressure Balance Valves
Labeled for ON/Off + Temperature (Hot to Cold)
Another differentiating feature of the pressure balance valve is that its compatible trim plate comes equipped with a single handle as opposed to two. This handle is used to turn the water on, regulate the temperature as well as the volume of the water. Although, the volume control component is often restricted to full flow by most manufacturers.
Thermostatic Shower Valves
A Thermostatic Valve is a type of valve that uses a thermostat to sense the incoming water and provide the most accurate temperature throughout your showering session. Because its job is solely to maintain temperature, it does not regulate the water flow as this is controlled by a separate component called the “Volume Control Valve”.
Like the pressure valve, the thermostatic trim plate is operated by a single handle or knob and is simply used to indicate the user’s desired temperature. Unlike pressure balance valves, this temperature indicator is reliable and does not need to adjusted depending on the weather. Each user can be assured that when they set the handle to their preferred temperature, that is exactly what they will get.
Thermostatic Shower Valve Trim
Labeled for Hot & Cold Only. Volume Sold Separately.
This goes without saying that since the thermostatic valve is able to maintain a consistent temperature throughout its use that it’s considered an anti scald valve.
Thermostatic valves are most commonly used in customer showers with multiple shower outlets. Think of a master shower with a showerhead, handshower, body jets and perhaps even an overhead rain showerhead. In these types of applications, individually are able to operate each outlet individually or all at once without the need of a diverter to switch back and forth.
In addition to the three main types of shower mixing valves, there are two other types of valves that often get lumped into the category: Volume Control Valves and Diverter Valves. While they don’t mix hot and cold water together, they are still necessary for a complete custom shower.
The diverter valve (or transfer valve) is an in wall rough valve that allows the user to re-direct water from one outlet to another. It does not regulate the temperature and is incapable of turning the water supply on and off. It can be a separate valve in the wall or a built in component of a main valve.
Transferring the waterflow is done by shutting off the supply from the one that’s currently open and open it up to an adjacent outlet. Some diverter valves allow you to have water flowing to two outlets at the same time but unlike volume controls, the water flow is limited as it’s shared between two components.
There are many types of diverter valves. The most common are the 2 way and the 3 way standalone valves. However, some diverter valves can be built in an existing main shower valve. Furthermore, there are ways to divert the water without using an in wall diverter (i.e. Tub Spout diverters, Shower Arm Diverters)
We go deeper on the many types of diverter valves in this article here –
Volume Control Valve
A volume control is a valve that is used to turn the shower on & off and control the amount of water flowing from an outlet. The volume control valve is used in conjunction with a thermostatic valve and is not compatible with any other for of shower valve.
Each volume control is designed to control a single outlet at a time. The only way to control more than one outlet with a single volume control is to pair it with a diverter valve. In this instance, the diverter would point to the desired outlet of your choice, while the volume control determines the amount of water flowing to it.
Keep in mind, that you would be limited by the amount of outlet that the diverter can point to. 2 outlets for a 2 way and three for a 3 way. In order to use 4 outlets, you would need to add an additional control. However the best practice is to just use 4 separate volume controls and control them individually.
Volume controls valves and trim most often come in a separate package than the thermostatic valve. However, manufacturers have started to produce all thermostatic valves with integrated volume control. This valve often come with an integrated diverter valve to accommodate 2 or more outlets.
Types of Shower Valve Configurations
Now that you have a better grasp on the type of shower valves that exist, it’s important to know how they are used in the field. After all, as someone using the shower, you only see the finish. By using the guide below, you should be able to tell which valves are used behind the wall just by looking at the finished product on the wall.
Pressure Balancing Valves With No Transfer Valves
Applications : Single Outlet Applications or 2 outlet application (when a bathtub spout has a built-in diverter valve.
Price: $ – The most affordable option out there besides a traditional Hot & Cold Valve.
How it works: A pressure balance valve with no diverter valve is the most commonly used configuration you will find. It is mostly used in single outlet applications. Think of a walk in shower with just one showerhead, or a walk in shower with a single handheld on a bar.
The one common exception is your typical bathtub & shower application where there is a diverter located on the tub spout. This is an inexpensive way for manufacturers to achieve a 2 outlet application with a simple single outlet valve.
Pressure balancing valves with built-in diverter valve (e.g. transfer valve)
Applications: Showerhead + Tub Spout, Showerhead + Handheld
Anti Scald: Yes
How it works: This is the same as a standard pressure balance valve but you have an additional component: a diverter located on the valve (as opposed to being separate). This built in diverter can be either a push button, a push/pull diverter, or a lever that moves side to side.
The purpose of the built-in diverter is to add a 2nd outlet.
It’s important to note that the built in diverter can’t be used in conjunction with a diverter tub spout.
For tub/shower application, a built in diverter is more durable than a diverter tub spout. Diverter tub spouts are often flimsy and an afterthought. It’s an affordable way to get 2 outlets without having to pay for the pricier valve.
Typical uses include: Showerhead + non diverter tub spout , Showerhead + handheld , Handheld + Tub Spout
Pressure balanced valve with separate transfer valves (2 or 3 way)
Applications: 2 or 3 outlet applications
How it works: In this setup, there are two separate valve bodies, your main pressure balancing valve and a separate diverter valve body. The main valve turns on the shower while also controlling the temperature of a single outlet. The additional diverter valve is added simply to direct the water to the available outlets (handshower, showerhead, or bathtub spout)
Important to note that in many cases the transfer valve can only direct the water to one outlet at a time. However, many manufacturers are starting to add the “shared function” option. With this option, you can have 2 outlets on at the same time.
Traditional 2 or 3 Handle Valve
Applications: Showerhead only (2 handle), Showerhead + Tub Spout (3 handle)
Anti Scald: No
How it works: It’s a simple 2 handle operation similar to your sink faucet. There is an addition of a third handle when you need to divert to a bathtub spout
A Traditional 2 handle valve is basically a separate hot and cold shut off. The major downside with this setup is that it’s not anti scald. If someone were to flush the toilet while you’re in the shower, you would lose most of your cold water all at once. As a result, you would get a burst of what is mostly scalding hot water.
Traditional 3 handle Valve : When a traditional 2 handle is paired up with a diverter, it becomes a 3 handle valve. The third handle is used to switch the water flow from the tub spout to the showerhead. This is common in older homes and apartment buildings.
Thermostatic Valves + Volume Controls
Applications: Can be used in a variety of shower setups
How it works:
Thermostatic valves are really just temperature controls. They allow you to have more controls over your shower’s temperature. Unlike the pressure balance valve, the valve alone cannot turn on your shower. Therefore, you will need 1 or more additional volume control valves to make it work.
A Thermostatic + Volume Control is the most common and also the most straightforward of all the setups. This setup includes one main thermostatic shower valve + one volume control for each outlet. Each volume control will turn on its respective outlet. In the meantime, the job of the thermostatic valve is to maintain a consistent temperature without deviating too much from its set temperature.
Thermostatic valve with 1 volume control and 1 transfer valve
Applications : 2 & 3 outlet applications only. Perfect for California which requires only one outlet at time.
How it works: This setup is very similar to Thermostatic + Volume Control option. The only difference it that it adds a diverter which allows you to have less hardware on your wall. Diverters are limited to 3 outlets.
The way to get more outlet is to add more volume controls and diverters. This is pointless as it rarely minimizes the number of hardware controls on your wall. It’s also important to note that diverter trims are typically much larger than volume controls.
This set up is seldom used in most cases. However , you may need to use if you live in California as the Golden State limits the number of outlets you can have on at the same time. Most manufacturers make diverters that only allow a single outlet to be used at a time. Therefore, if you live in California, your plumber may have to use this setup as an option instead.
Thermostatic valve + integrated volume controls
Applications : 1 to 3 outlet applications
Key Benefits: Small footprint on your shower wall. Perfect for someone who needs a minimalistic look with a lots of function.
There are many configurations that fall in this category: the push button style, the traditional knobs style, and the all in one Diverter + Volume Control.