Does A Dishwasher Need Hot Water

One of the best tools to have available to you in your home is a dishwasher. This takes the load off of your shoulders when it comes to cleaning up after cooking good food. Dishwashers are designed to utilize strong water pressure and hot water to ensure all your dishes get perfectly clean. Most dishwashers will use large amounts of water per cycle. But only a few of the processes during the cycle times will actually use hot water.

But does a dishwasher need hot water to properly wash your dishes and cutlery? Just keep reading and we will answer that question. We will also look at questions you may have about a dishwasher’s preferred water temperature. Can it affect the performance of the dishwasher? Keep reading to find out.

How Does A Dishwasher Work?

A dishwasher is a simple machine to understand. The unit starts by utilizing your basic plumbing to pipe in normal water that is unheated. Once the water has reached the interior of the machine, it is kept in a small reservoir in the bottom of the dishwasher, where a heating element then begins to warm the water up. How hot the water temperatures get in the machine will vary from model to model but tends to fall between 86° and 140°F.

After the water has come up to temp, the unit then begins using an electrical pump to push the water up through the walls of the unit. Once the water has been pushed up through the walls, the water begins to be pushed out by jets from the holes that are placed at the bottom and the metal paddle that is housed in the unit. As this happens, there is also a portion of the unit’s water that is left cooler than others. This is pushed out through holes in the top and the other paddle built into the design.

As the water drips off the plates, it then falls back into the bottom of the dishwasher and is heated up to be pushed through the cycle again. This, of course, is all assisted by the dishwasher soap or tablet that has fallen out of the dispenser upon the closure of the door. That is the basic working of every dishwasher though there may be varying levels of additional processes during the wash cycle.

Can You Run A Dishwasher With Cold Water?

When it comes to the question of using a dishwasher with cold water, the biggest issue is, of course, going to be the performance of the machine. Many people use harsh dish soaps and chemicals. Utilizing cold water will make it harder to rinse these chemicals and soaps away. But it will also decrease the efficiency of the rinse cycles.

Hot water is ideal for getting rid of crusted food and killing germs that may be present, whereas cold water is lax in this department. The dishwasher itself, of course, will cycle as normal with or without hot water. But it may take a few extra times through the washing cycle to ensure that your dishes are clean and ready to be used for the next meal.

How Cold Is Too Cold for a Dishwasher?

Though a dishwasher will work using cold water, there is a limitation on some models. For many, if the water being used is below 120°F, then as the dishwasher attempts to heat that water, it will find itself lacking the ability.

Because of the extended heating time for this water, the dishwasher will take extra electricity, which could mean higher bills. It also could overwork the machine and shorten its life cycle. For those that live in areas where they have parts of the year where water continually freezes, making sure that they have a good hot water tank will decrease the chances of dealing with this issue.

How Much Water Does A Dishwasher Use?

Depending on the model of dishwasher, you may find yourself using quite a bit of water. There are some more energy-efficient models available today that may only use 1 ½ gallons of water, but for the most part, the other models may use up to 8 gallons of water per cycle.

The only way to know for sure how much water your dishwasher will use is to check the user manual, where typically, these metrics are written down. Understanding all of this will help you be more mindful of the energy used so that you can manage your budget easier.

What About Manual Loading Of Water in a Dishwasher?

If you have a good hot water tank, then you may be able to save a little on the budget by purchasing a dishwasher that is not designed with a built-in water heater element. This will mean that you will have to load the water manually. These types of units may not give you as much water pressure and will cause the temperatures of the hot water to be inconsistent.

The hot water varies, of course, because of your ability to manually heat the water for the unit. You have to be very careful as well because these units have a definitive temperature that they can use. If you exceed this, much like with using freezing water in a standard dishwasher, you may find yourself damaging the dishwasher. This can affect the overall performance of the unit.

Close up shot of woman's hand taking out clean dishes from dishwasher machine


Even with all that information about if a dishwasher does truly need hot water, there are probably still a few other questions floating around your mind. So here are some of the most commonly asked questions that we answered in hopes we could help you further.

Do Dishwashers Need Direct Hot Water Input?

Whenever someone purchases a new dishwasher and needs to install it, this is one of the most common questions asked. Do you need a hot water input connection or not? While most installations prefer hooking it up to a hot water input, you don’t need to. Most modern dishwashers are designed with a built-in heating element.

Many models are designed specifically with a direct hot water connection. This will hook up directly to your hot water pipe. This means if your home has a hot water connection that allows for temperature settings to be set by hand, you have many different options available to you.

Is Hot Water Needed for the Dishwasher, or Does It Heat Cold Water?

Though there is plenty of water used in the dishwasher wash cycle, the unit itself does not fill up with water. Instead, it fills a small reservoir that has a heating element. That then heats the water and is pumped through the system, spraying the dirty dishes. So most dishwashers don’t necessarily need hot water to work. They heat the incoming water so that it is able to give your dishes a proper cleaning.

Will a Dishwasher Work Without Hot Water?

There are many reasons why people may be considering using cold water in their dishwasher. It could be because they have a broken water heater or just because they’re trying to be eco-conscious. Most washers are hooked up to the valve that goes straight to your cold water supply. However, there are some that are designed to be hooked up straight to hot water.

However, there can be an issue with the dishwasher if the water is too cold. It may lead to error codes popping up. This is the machine simply telling you that the water is not hot enough to be able to deliver clean dishes.

Do Dishwashers Heat Incoming Water?

There are many different designs and models when it comes to dishwashers. No matter what type of model, though, the unit will use lots of water. This often leaves people wondering if dishwashers heat incoming water to maintain their hot water supply.

After you stack your load of dishes into your dishwasher, you turn on your wash cycle. Water will begin to collect in a small reservoir where a heating element is housed. The heating time of this water is not very long. Eventually, the high-temperature water for cleaning is pumped through the jets and cleans your dishes. So yes, dishwashers are designed with the ability to heat water.

Final Thoughts

Having a high-performing dishwasher in your home can save you time and money, which is something we all love. There are many energy-efficient models of dishwashers available out there. Running your dishwasher with cold water or even warm water is possible. But it is not recommended if you’re looking for a good proper cleaning of your dirty dishes.

Whether your dishwasher needs hot water or not may depend on the machine itself. Some are set up to be hooked up directly to hot water inlets. The majority are crafted to hook up to the cold water one. So take a look at your specific dishwasher to find out what is needed for your machine.

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