Choosing Between A Pressure Balance and Thermostatic Shower Valve

Here at Toulmin Kitchen and Bath, we believe that an educated homeowner is our best customer. When you educate yourself about the process and products available to you, you'll have a better understanding of your options and the ability to make informed decisions when planning your project. 

In this post, we're going to look at a t4echnical aspect of bathroom remodeling that can help you to create a safer and most enjoyable showering experience. When remodeling your bathroom, you'll have plenty of decisions to make about finishes, fixtures, and materials. One crucial decision that is hidden behind the wall, but is vital to the functioning of your shower, is what type of shower valve is best for you?

Pressure Balance vs. Thermostatic Shower Valves

Your shower is an integral part of your bathroom ritual, not only for promoting good personal hygiene. Showers help us to maintain our sense of well-being and confidence while offering us respite and peace from the stresses of the day. 

However, the perfect shower can be easily ruined by something as simple as your wife starting a load of laundry, or the downstairs toilet being flushed! While at best, it's an annoyance, at its worst, it can be highly dangerous: extremely hot or cold water suddenly bursting forth from the showerhead can make us jump, scramble, or panic. In the chaos, you can seriously injure yourself if you slip and fall. If the water is hot enough, you can be severely scalded in a matter of seconds.

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Safeguarding against thermal shock and scalding in one of the most important things you can do when designing your bathroom, especially if you have young children or elderly adults living in your home. The most effective way to do this is by installing an anti-scald device at the shower fixture. 

There are two primary types of devices to do this: pressure balance valves and thermostatic valves. While they are not a requirement for either remodeling or new builds in the building codes, they are a smart addition that can keep everyone in your home safe and comfortable in the shower.

The main difference between the two? A pressure balance valve senses and controls the ratio of hot and cold water. A thermostatic valve senses and controls that actual water temperature. So which works best? It depends on your preferences and your budget. Let's look at how each type of valve actually works.

How A Pressure Balance Shower Valve Works

A pressure valve uses a single handle to control both the volume and temperature of the water, along with a dial or set-screw that sets the stop point for the handle – the max ratio of hot to cold water. The pressure is balanced by either a sliding disc on a piston or a spool that reacts to changes and maintains the pressure ratio. When someone flushes the toilet, cold water is sent to the toilet tank, reducing the cold water pressure arriving at the shower valve.

When this happens, the mechanism inside the pressure valve moves to reduce or cut off the hot water maintaining the balance between the hot and cold flows, making the temperature fluctuate just a few degrees. Remember, a pressure valve does not pay attention to temperature, so if the valve is set to the maximum temperature, and the handle turned all the way to hot, the water coming out of the shower is the same temperature as the water leaving the hot water heater. 

How A Thermostatic Shower Valve Works

Thermostatic valves have two handles. One controls the temperature, and the second controls the flow. Thermostatic valves react to temperature, not water pressure. With this type of valve, you can change the water flow without affecting water temperature. This is great for water conservation; simply turndown the flow while you're shaving or shampooing. 

This is possible due to a wax element in the valve that reacts to heat by expanding or contracting. When the water exceeds the maximum temperature, the element expands to restrict flow and allow more cold water into the mix. Should either hot or cold supply fail, the valve shuts the flow from the other side. 

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The significant advantage of a thermostatic valve is that it allows you direct control over output temperature. You can safely set your water heater to 140 degrees F to inhibit bacterial contamination, and the water coming out of your showerhead can always stay 100 degrees. Just set the maximum output temperature directly on the valve.

Choosing The Right Shower Valve

Either type of shower valve offers clear benefits if you have small children or elderly adults living in the house. Think about your household; if it's just you and a partner, a pressure balance valve should be problem-free. You can easily adjust temperature and flow to meet your preference. They also have the added benefit of being more economical than a thermostatic valve. 

If you're not sure or your not a "precision" type of person, a thermostatic valve might be a better choice. With the max temperature set, even if you inadvertently turn the temperature valve all the way up, the temperature will never exceed the pre-set maximum. With a pressure valve, accidentally turning it all the way up can result in scalding temperatures. 

Most of the popular manufacturers like Delta, Kohler, Grohe, Waterworks, and Brizo, for example, offer fixtures that feature both types of shower valves. Fixtures that feature a thermostatic valve tend to be pricier than their pressure balance counterparts, so you may need to take your budget into consideration.

If you're not sure which type of shower valve is right for your project, your design-build team can help you to better understand your options and make a perfect choice.

About Toulmin Kitchen & Bath

If you're considering a bathroom remodeling project and you live in the greater Tuscaloosa area, give the experts at Toulmin Kitchen & Bath a call at (205) 366-0807 to schedule a free consultation. Let us design the perfect spa-like bathroom you've been dreaming of, complete with the ideal shower valve!