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What Are Thermostatic Mixer Valves?

Thermostatic Mixer Valves (sometimes referred to simply as TMVs) are temperature control devices which are commonly installed in water outlets used in baths, showers, sinks, and bidets. They are designed to maintain your chosen water temperature, preventing sudden surges of either hot or cold.

How do Thermostatic Mixer Valves Work?

Thermostatic mixer valves use an inbuilt sensing mechanism to automatically blend the input of hot and cold water into the temperature desired by the user. If the input of either hot or cold water changes, this creates a variation in the supply pressure and temperature within the valve. When either of these deviations occurs, the mechanism will shut down the flow of water from the opposite side to equalise the flow and temperature.

Unlike most previously technology designed to prevent changes in temperature, thermostatic mixer valves sense both water pressure and temperature, making them safer and more reliable.

Why is it Worth Installing a Thermostatic Mixer Valve?

A fall or rise in temperature might only sound like an annoyance, but they can often be dangerous. For example, the blast of hot water which results from a sudden drop in cold water pressure can be extremely alarming. Even if no scalds occur, the shock can easily cause somebody to trip and fall. This can lead to serious injury.

Scalding itself represents just as big a cause for concern. Around 20 people die each year as a result of scalds caused by hot bath water, while around 570 suffer severe burns. Young children have sensitive skin, and the elderly generally suffer from decreased reaction times, so these groups are at the most risk.

Aside from safety concerns, thermostatic mixer valves are also just far more convenient. Since your water is mixed to a pre-selected temperature, you won’t need to spend time adjusting the flow yourself before stepping into the shower or bath. If you need to stop the water for any reason, the mixer valve can automatically find the same temperature once you turn it back on again. This doesn’t just save you time, it also saves you money on your heating and water bills.


Thermostatic mixer valves make washing safer, easier, and more economical. If you don’t have one already, they’re well worth investing in.