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What is a Hot Water Tempering Valve And TMV And Why Do We Need Them?

What is a hot water tempering valve and TMV and why do we need them?
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Having hot water at home is something we all need and love. It helps us with everything from taking showers to washing our dishes. But, there’s something important behind the scenes making sure the hot water is safe to use – that’s the hot water tempering valve and the Thermostatic Mixing Valve (TMV). These special parts in our water systems help control how hot the water gets, so it’s just right and safe, not too hot or too cold. In this blog, we’re going to talk about what these valves are and why they are so important for keeping our hot water safe. It’s all about making sure we can use hot water comfortably and safely every day.

What is a Hot Water Tempering Valve?

A hot water tempering valve is a clever device that plays a big part in keeping the hot water at home just right for us. Imagine it as a guardian that makes sure the water isn’t too hot that it could burn you. This valve works by mixing the hot water coming from your heater with some cold water to lower its temperature to a safer level before it comes out of your taps.

The main job of the tempering valve is to keep you and your family safe from getting scalded by water that’s too hot. It’s like having a smart mixer that knows exactly the right mix to make the water warm and comfortable, not scalding. This is especially important in homes with little kids or elderly people, where the risk of burns from hot water needs to be very low.

So, in simple terms, a hot water tempering valve adjusts the temperature of the water coming out of your heaters, making sure it’s just right for everyday use. It’s an essential part of the hot water system in your home, working quietly behind the scenes to keep everyone safe.

The Role of TMV in Your Hot Water System

A Thermostatic Mixing Valve, or TMV, plays a crucial role in making sure the hot water in your home is both safe and comfortable to use. Unlike the hot water tempering valve, which mixes hot and cold water to prevent scalding, a TMV does this with a bit more finesse. It’s designed to quickly adjust the water mix based on any changes in water temperature. This means if the hot water gets too hot or the cold water too cool, the TMV reacts instantly to keep the water temperature just right and safe for everyone.

TMVs are particularly important in places like hospitals or care homes, where it’s vital to prevent scalding among people who might not react quickly to sudden changes in water temperature. They are smarter than hot water tempering valves because they can adjust more quickly to changes, ensuring the water temperature stays consistent, no matter how the supply temperatures fluctuate.

So, while both TMVs and hot water tempering valves aim to keep you safe from hot water burns, TMVs take it a step further by offering faster and more precise control over water temperature, making them an essential part of maintaining a safe and comfortable water temperature in sensitive environments.

Why Are These Valves Necessary?

Hot water tempering valves and TMVs are not just fancy bits of plumbing; they’re essential for keeping us safe. First off, they help prevent scalding. This is especially important in homes with young children or elderly residents, who are more vulnerable to serious burns from hot water. By controlling the water temperature, these valves make sure the water is warm enough for our needs without being dangerously hot.

Another critical reason for these valves is to stop the growth of harmful bacteria, such as Legionella. Legionella can grow in water systems that aren’t hot enough, leading to serious illnesses if people are exposed to it. By ensuring the water in the system stays at a safe temperature, these valves help keep our water supply healthy.

In Australia, there are strict rules about water temperatures in different settings. For example, in healthcare and aged care facilities, water must not exceed 45°C to protect those who are most at risk. In residential settings, the maximum is usually set at 50°C. These standards are in place to balance the need for safety with the need for effective cleaning and bathing temperatures.

For new buildings or when you’re renovating your bathroom or hot water system, fitting a tempering valve or TMV is a must according to the regulations. This isn’t just about meeting legal requirements; it’s about ensuring the safety and well-being of everyone who uses the hot water. So, these valves are a crucial part of any hot water system, keeping the water at just the right temperature for both comfort and safety.

Installation and Maintenance

Installing a hot water tempering valve or a Thermostatic Mixing Valve (TMV) is something best left to the professionals. Both types of valves are key parts of your home’s hot water system, and getting them set up right is crucial for them to work properly. When installing, a skilled plumber will make sure the valve is correctly connected to your hot water system. They’ll adjust it so that it mixes hot and cold water to the safe temperature that Australian standards require.

It’s not just about putting these valves in place, though. Regular maintenance is equally important to keep them doing their job. Over time, valves can wear out or get blocked, and if they’re not checked and serviced, they might not control the water temperature safely. This is why it’s recommended to have your valves checked by a plumber at least once a year. They’ll make sure everything’s working as it should, and can replace parts if needed. This keeps your hot water safe from being too hot and prevents bacteria from growing.

In short, the right installation by a pro and keeping up with maintenance checks are key to making sure your hot water is always safe and at the right temperature. It’s about keeping your system efficient and your home safe.

Choosing Between a Hot Water Tempering Valve and TMV

When it comes to ensuring the safety and efficiency of your hot water system, deciding between a hot water tempering valve and a Thermostatic Mixing Valve (TMV) is crucial. The choice largely depends on the type of property and the specific needs of its occupants. For residential homes, a hot water tempering valve is often sufficient, providing a balance of safety against scalding while being cost-effective. These valves are designed to mix hot and cold water to a safe temperature, suitable for daily use.

On the other hand, commercial settings, healthcare facilities, and places caring for the vulnerable or elderly may require the more responsive and precise temperature control offered by TMVs. Although TMVs come with a higher upfront cost, they are invaluable in environments where the risk of scalding must be minimised, and water temperature needs to be carefully managed.

When considering the lifespan and maintenance costs, TMVs, while more expensive initially, may offer better long-term value by ensuring a safer environment and potentially lower maintenance costs due to their durable design. Ultimately, the decision should be informed by the specific requirements of the property and its users, balancing cost against the need for precise temperature control and safety.


Understanding and choosing the right valve, be it a hot water tempering valve or a TMV, is key to ensuring our hot water systems work safely and efficiently. These valves control water temperature and protect us from scalding and harmful bacteria. Whether it’s for a home, a business, or a healthcare facility, getting the right valve installed can make all the difference.

If you’re unsure which valve is best for your needs, or if you need help with installation and maintenance, our team at Sydney Essential Plumbing Services is here to help. Our experts can provide you with the advice and services you need to ensure your hot water system is safe, efficient, and compliant with Australian standards.

Don’t hesitate to reach out for professional guidance. Whether you’re installing a new system or upgrading an old one, make sure it’s done right. Contact Sydney Essential Plumbing Services today to ensure your hot water system is in the best hands.

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