Hot Water Mixing Valve Buying & Installation Tips

Hot Water Mixing Valve Buying & Installation Tips

Charlie Hardcastle

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Do you find that the water in your home varies from scalding hot to freezing cold and struggle to get it anywhere in between? A hot water mixing valve could be the solution to your problems!

Here we look at how to find the perfect hot water mixing valve for you and also offer installation tips. 

What Is A Hot Water Mixing Valve? 

A mixing valve is a mechanical device that mixes hot and cold water to then deliver mixed water downstream, which ultimately flows out from your faucets, shower, or into your bathtub.

These devices are brilliant for anyone who has young children in their home as it prevents water from flowing that is extremely hot and could scald a young child.

The cost of a mixing valve varies, depending on the material it is made from, the type you are planning to buy, and whether it is for commercial or private use.

While they can cost anything over $100 they are deemed worthwhile by most people who have one fitted.

There are different types of mixing valves which all offer a different way to maintain a peak hot water temperature in both commercial and domestic (see also ‘Domestic Hot Water: An Overview‘) settings.  

Buyers Guide 

There are a number of considerations that can help narrow down your search when buying a mixing valve, these are explained below. 


There are a number of different types of mixing valves but in essence, they all do the same thing, which is to provide water at a safer temperature.

Each different type meets various installation requirements and some may be better suited to the water heater and pipework in your home than others. 

The most popular sized mixing valves are the ½” and the ¾” as these are the most common fittings on a range of water heaters.

You can find mixing valves in these sizes that are hydraulically or thermostatically operated and also as 3 or 4-way motorized valves. We explain these different types below.

Hydraulic Mixing Valve 

This type of mixing valve is hydraulically operated and is referred to as a pressure balanced type also.

The hydraulic mixing valve has a stainless steel spring that is loaded into the main water supply and it is this that allows the cold to mix with the hot water. 

Hydraulic mixing valves are usually made of brass to prevent corrosion and they require manual adjustments as they cannot automatically control the outlet water temperatures as other types do. 

Thermostatic Mixing Valve 

A thermostatic mixing valve mixes hot and cold water together, ultimately producing a maintained, constant temperature even when pressures and temperatures may vary.

The temperature that is maintained is set by the user. 

There is a mechanism in the valve that is thermally sensitive and this allows the water to mix properly. The result when using this type of mixing valve is very precise.  

3-Way Motorized Mixing Valve 

Motorized mixing valves used electronic controls and sensors that help maintain or restore peak water temperature under peak loads.

On a 3-way mixing valve, there are three ports, one for cold, hot, and mixed water, the temperature of which is pre-set by the user.

The valves use the motorized actuators and the electronic temperature controllers to self-adjust.

4-Way Motorized Mixing Valve

This model operates similarly to the 3-way motorized mixing valve but it has a 4th port which is used to feed excess mixed water back into the cold water.

This is a great choice for anyone that requires a large volume of tempered water at certain times. 

Hot Water Mixing Valve Buying & Installation Tips (1)

Reputable Brands

There are a number of brands that have been manufacturing top-quality mixing valves for many years and when shopping for a mixing valve you should look for one of the brands below. 

  • Danze
  • Danfoss
  • Heimeier
  • Honeywell
  • Leonard
  • Watts

Each brand caters to a different budget range but all offer good quality products.

When purchasing a mixing valve (see also ‘Best Mixing Valve: Important Piece Of Plumbing‘) from one of these brands ensure you enquire about any warranty that you may be able to avail of. Warranties are a great way of protecting your purchases and your investments. 


Whether you have a big budget or a tight budget there are a lot of choices when shopping for mixing valves.

If you want to stick to your budget we recommend shopping around. Often purchasing directly from the manufacturer you may find discounts or get access to better warranties. 

If you have a particular type of mixing valve you want to find, check online and in other stores, and often you will find somewhere that has the product for slightly cheaper or they may have a new customer discount code. 

Installation Tips 

When you are installing a mixing valve it is important that you take time to read the instructions that come with the mixing valve.

If there are no instructions you should take the time to research online on how best to attach the mixing valve to your water heater. 

It could take up to 2 hours to fully complete the installation so it is quite a big task.

If you do not feel comfortable doing this yourself we recommend getting a professional to prevent any damage to your water heater and pipework due to unsteady or nervous hands. 

Anyone with basic plumbing experience or who is a confident do-it-yourself enthusiast should be able to install a mixing valve using everyday tools.

Precautions should be taken when working with water, particularly hot water. 

When installing a hot water mixing valve,  they can be put directly onto the water heater outlet and this enables the device to ensure that mixed, or tempered water is delivered everywhere in your home. 

Safe & Unsafe Water Temperatures

All water heaters are built with a thermostat (see also our guide to wiring water heater thermostats) included, the factory set temperature is usually 120 degrees Fahrenheit. 

Water at this temperature can take 5minutes to cause 2nd and 3rd degree burns on an adult’s skin and so most people will adjust this temperature so that it won’t lead to any potential burns.

Water heaters that have hot water from 68 degrees to 122 degrees Fahrenheit can also lead to the development of the sometimes deadly bacteria, Legionella. 

Temperatures that should be avoided would be anything over 130 degrees Fahrenheit. At 30 degrees, it only takes as little as 30 seconds to burn adult skin and 160 degrees can cause burns in as little as 0.5 seconds.

When installing a mixing valve you should check and adjust the temperature on your water heater so that the mixing valve will have an easier job preventing any burns or injuries.

Hot water poses many risks and so it is extremely important that the necessary precautions are taken. Installing a mixing valve is a great way of protecting you and others. 

When a mixing valve is installed, a temperature of 130 degrees Fahrenheit is recommended as this will be warm enough to wash dishes and prevent harmful bacteria from developing, 

Final Thoughts

We hope that this guide has been helpful to you and that you will be able to find a great mixing valve that will suit your needs.

Say goodbye to unsafe, extremely hot water (see also ‘Hot Water Not Hot Enough: Common Problems and How to Fix Them‘) and say hello to constant tempered water flowing through your commercial or domestic property. 

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