Shower Valve Buying Guide: Which is the Right Valve for Your Needs?

How to Choose the Right Shower Valve

Showers are more than the visible components such as the faucet, shower head, body sprays, and shower controls. Valves installed behind the stylish fixtures play a big role in your shower’s functionality. The shower valve is what keeps your shower from becoming excessively hot if a toilet is flushed, and maintains a constant temperature when other water fixtures such as a sink faucet are used. Surges in water temperature can be dangerous, causing potential scalding injuries from the too hot water and leading to surprise slips and falls when trying to avoid a sudden change to icy cold or steaming hot water. To mitigate such surges, you need the right type of shower valve.

Before buying a shower valve for your bathroom, whether you are building a bathroom in a new construction or remodeling or replacing outdated fixtures in an existing room, you should know the different types of valves are available and how they are used. 

Types of Shower Valves 

What is a Shower Valve?

All shower fixtures require two components to work: the trim set which is the visible faucets, controls, and hardware such as a shower head, tub spout, etc. that you use every day, and the shower valve which is the non-visible element that allows the trim sets to function. A shower valve is the inner device within the wall that regulates the water temperature, water flow, and output to the shower head, handshower, tub spout, and body sprays. Also know as a rough-in valve, the shower valves are connected the plumbing supply pipes. A cartridge in the valve connects it to the external trim handles that you use to operate the faucet and shower controls.

Here is a comparison of the most common types of shower valves and what functions they provide. 

Pressure Balancing Shower Valve

One of the most common types of shower valves, the pressure balancing shower valve automatically control the balance of the water pressure between hot and cold water. Also known as an anti-scald valve or shower pressure valve, it detects changes in water pressure from both the hot and cold-water supply lines as the water passes through a set of pistons and diaphragms within the valve. It restricts one side or the other to “balance” the temperature and ensure it remains steady within 2-3 degrees.

Most pressure balancing valves use a single handle (or knob) that turns left and right to control both the water pressure and the temperature. With most valves of this type, you can’t control the volume of water, though some designs do have a separate lever to control the volume. Because pressure balancing valves are the most affordable option, they are the industry standard and are found in most hotels, commercial applications, and many homes.

Thermostatic Shower Valve

Thermostatic shower valves have two valves and two handles to control both the water pressure and the temperature, allowing you to set the temperature without affecting the water volume, and vice versa. A thermostatic valve uses a thermosensitive element such as a wax insert to sense and control the water temperature. This element expands and contracts as needed, resisting the water supply when the temperature reaches the desired heat threshold.

This valve gives you direct control over the temperature by presetting the preferred water temperature or by setting the overall temperature limit on the valve. You can also set your desired water temperature with the handle, so the water will be at that same temperature the next time you use the shower. While a thermostatic shower valve offers superior control functionality, it is more expensive than a pressure balance valve.

Shower Mixing Valve

The older style shower mixing valve is a manual valve sometimes still found in older homes. This valve mix mixes the cold and hot water from the supply pipes before sending it through to the shower head. A mixing valve is prone to the risk of scalding if the cold water pressure drops since it is unable to regulate any sudden fluctuations in pressure. This outdated shower valve is no longer permitted in new construction and should be upgraded to a pressure balancing valve or thermostatic shower valve during a bathroom remodel.

Shower Diverter Valves

As the name implies, shower diverter valves divert water from one outlet to another in your shower such as from a tub spout to a shower head or from a shower head to a handshower. Since most standard showers have one shower head, a diverter valve is typically since in tub/shower combinations. There are three different types of diverter valves:

• Tee diverter: Diverts water from the bathtub spout to the shower head using a pull arm to block the flow of water from the tub faucet once the desired temperature is reached.
• 2-way diverter: Uses a rotating handle to control the water temperature while another knob redirects the water between the shower, tub, or other sprays such as a handshower.
• 3-way diverter: Uses two knobs to control the hot and cold water and a third knob or handle redirects the water between the shower outlets (tub, shower, other sprays).

Shower Transfer Valve

Designed for use in showers with multiple shower heads, faucets, and body sprays, a shower transfer valve distributes water flow to multiple outlets either alternatively or simultaneously, depending on where you want the flow of water. Thus, you can run a shower head along with body sprays or a handshower, or have the water only come out a single fixture.

Concealed vs. Exposed Valves

Although most shower valves are concealed within the wall of your shower where it is not seen, some showers use an exposed valve which is mounted in view on the tile or surface of the shower wall. This type of valve is easy to install, easier to repair, and allows retrofits of trim on older showers without opening the wall or changing out the wall tile. A wall-mounted exposed shower kit usually consists of a shower faucet, overhead shower head, and a handshower. Concealed valves embedded in the wall maximizes shower space offers a more streamlined aesthetic.  

How to Choose the Correct Valves

Because your shower trim and valves work in tandem, it’s important to identify the type of faucet and valve in your existing shower before replacing or repairing a component or your entire shower system. If simply replacing your faucet trim, you can keep the valve if it’s compatible with your new trim and in working order. If you are installing a new trim from a different manufacturer, you will also need to replace the valve with one that is designed for use with that faucet. Here’s some ways to determine the type of faucet you have along with the valve you need:

1. Count the number of shower faucet handles:
   1. No handles indicate water flow and temperature are controlled by a panel with buttons.
   2. A single handle controls both flow and temperature with the one handle.
   3. Two handles control hot and cold water through each handle.
   4. Three handles control hot and cold water with a diverter handle to distribute the flow between outlets.
2. Determine how the shower faucet is connected:
   1. A fixed shower head will connect directly via a shower arm to the shower pipe in the wall. This stationary shower head may or may not allow the water flow angle to be adjusted.
   2. A handheld or handshower uses a hose that runs from the shower head to the shower pipe behind the faucet handle or uses a separate outlet. A handshower gives you the flexibility of being able to move it around to direct water where you want it.
3. Identify the manufacturer of the valve:
   1. You can determine the manufacturer of your existing valve by the brand indicated on your shower trim by a logo or letter on the faucet. Trim from one manufacturer is usually not compatible with another brand of valve.
   2. Also check with the manufacturer to see what valves are compatible with specific types of trim, as some trim within each brand requires a particular model valve.
4. Check the shower cartridge:
   1. You can also identify the shower valve manufacturer by removing and checking the cartridge for the brand name.
   2. Do not mix and match manufacturers on your shower faucet and valve parts. Different brands are not interchangeable and will differ in valve types and sizes. 

Care and Maintenance of Your Shower Valve

A quality shower valve made by trusted manufacturers such as Moen, Delta, American Standard, Grohe, hansgrohe, and Symmons are built to last for a long time even with heavy use. Use a shower regularly will help keep the valve in optimal shape since a infrequently used shower system can develop problems faster. If you have hard water, install a water conditioner on your water heater to reduce buildup of scale which can affect the performance of your valves and faucets.

Replace valve cartridges when needed as they can wear over time. Thermostatic valves are especially prone to dirt and debris buildup compared to pressure balancing valves. In pressure balancing valves, the spool can stick when there is hard water buildup inside the cartridge. If your water temperature or volume seems unequal, improperly balanced, or if the flow stops altogether, inspect and clean the check valve per the manufacturer’s instruction manual. If that doesn’t resolve the issue, replace the cartridge.