As a home appliance expert with extensive experience in the field, I often get asked about the best practices for operating dishwashers. One common question is whether it's necessary to run hot water before starting the dishwasher. The answer to this is nuanced and depends on several factors, including the type of dishwasher you have, the water temperature settings, and the water supply system in your home.

Firstly, it's important to understand how a dishwasher works. A dishwasher is designed to clean dishes using a combination of water, detergent, and heat. The water is typically heated by the dishwasher's built-in heating element to a temperature that is effective for removing grease and killing bacteria. Most modern dishwashers are equipped with a heating element that heats the water to a preset temperature, usually around 130 to 150 degrees Fahrenheit (54 to 65 degrees Celsius), which is sufficient for cleaning and sanitizing.

Now, let's address the question of whether you should run hot water before starting the dishwasher. In most cases, you do not need to manually run hot water before starting the dishwasher. Here's why:


1. Automatic Heating: Modern dishwashers are designed to heat the water automatically. As soon as you start the dishwasher, the heating element begins to work, and the water is heated to the necessary temperature for cleaning.


2. Water Supply System: In many homes, the hot water supply system is designed to deliver hot water quickly. This means that by the time the dishwasher starts to fill, the water from the hot water heater has already reached the dishwasher, and it is already hot.


3. Energy Efficiency: Manually running hot water before starting the dishwasher can be a waste of water and energy. It's more efficient to let the dishwasher do its job and heat the water as needed.

However, there are a few scenarios where you might consider running hot water before starting the dishwasher:


1. Cold Water Supply: If your home has a long distance between the hot water heater and the dishwasher, or if the hot water supply is slow, the initial water that fills the dishwasher might be cold. In such cases, running hot water for a few moments can ensure that the dishwasher starts with hot water.


2. Heavy Soiling: If you have dishes with heavy soiling or baked-on food, starting the dishwasher with hot water can help in breaking down the residue more effectively.


3. Dishwasher Issues: If your dishwasher is not heating the water properly or if the heating element is malfunctioning, running hot water before starting the dishwasher can be a temporary solution.

It's also worth noting that some dishwashers have a feature that allows you to set the water temperature manually. If your dishwasher has this feature, you can set it to use hot water from the start, eliminating the need to run hot water manually.

In conclusion, while it's generally not necessary to run hot water before starting the dishwasher, there are specific situations where doing so might be beneficial. It's always best to consult your dishwasher's user manual for specific instructions and recommendations tailored to your model.

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Well, neither does your dishwasher. ... Run hot water before starting the dishwasher: Before starting the cycle, turn on the faucet and run until the water is hot to the touch. This means your first dishwasher fill cycle will be hot, instead of cold, until it finally makes its way over from the hot water heater.Oct 10, 2016read more >>