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Differences Between Pressure-Balanced and Thermostatic Showers

If you have just about had it with having your shower interrupted by blasts of scalding hot water because somebody flushed a toilet, it is time you did something about it. This doesn’t mean telling your family members or roommates to not flush the toilet while somebody is showering, because you’ve likely already tried that a million times and it’s clearly not working. There are a couple of types of shower valves you can install in your shower: pressure-balanced and thermostatic. These valves are such a good idea that most areas require new homes to have one or the other. You can call for an expert in plumbing by Roto-Rooter to install either, but before you choose which one, you need to understand the differences.

Temperature Control

Both pressure-balanced and thermostatic valves are designed with temperature control in mind, but each operates in its own way. When a toilet flushes, showers lose cold water pressure, which leaves un-tempered, scalding hot water to burn your body. A pressure-balanced valve uses a shuttle piston to balance the hot and cold water pressure, even when one line has a sudden loss in pressure. A thermostatic valve actually measures the temperature of the incoming hot and cold water, and adjusts the amounts of each to maintain a constant temperature. Thermostatic valves typically do a better job of maintaining temperature, and they have a safety feature, which shuts off the water if one of the supplies fails.


Many people may be wary of either of these valves, and may even dread having to install them because they’re worried they will be sacrificing flow rate. While these views are common, neither of these valves will actually reduce flow rate, except in the situation that a large amount of pressure is lost from one of the lines. Many other recent plumbing code changes were made to address flow rate and water efficiency, but these valves’ major role is to protect you from scalding hot water. As a side note, most low-flow shower heads are designed to provide the same amount of pressure and spread as older, heavier flow models.


When it comes to price, pressure-balanced valves are more affordable. If you are trying to meet plumbing codes without breaking the bank and haven’t had issues in the past, this valve will meet your needs. A thermostatic valve will cost you around double of what you would pay for other valves, but the price increase may be warranted because of its more advanced mechanisms.



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