Do You Put Hot or Cold Water in a Humidifier?

Using the right water temperature in your humidifier is important for prolonging the longevity of your product. Aside from the water temperature, it is also important to learn about the type of water that you should use in your humidifier.

Short Answer

You should put cold water in a humidifier regardless of whether you are using a cool-mist or warm-mist humidifier in your home. You could also opt to put warm water instead of hot water in your humidifier to prevent damage. If you opt to use warm water, ensure that the temperature of the water is not significantly higher than your room temperature.

This article will enlighten you about different humidifiers and their recommended water temperatures. It will also help you understand why using hot water in some humidifiers can damage the internal components of your humidifier. Continue reading for more insights.

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Comprehensive Answer: Do You Put Hot or Cold Water in a Humidifier?

Generally, it is recommended to put cold or room temperature water in your humidifier regardless of whether you are using a cool mist or a warm mist humidifier. Using cold water ensures that the high water temperature of hot water will not damage your humidifier.

Below is a list of reasons why you should use cold or room temperature water in your humidifier.

Reduce risks of damage

Using cold or room temperature water will reduce the risks of damaging your humidifier, especially if the humidifier has not been designed for hot water purposes.

Low risks of injuries

You have a lower likelihood of getting burned when using cold water. Pouring hot water in a humidifier can lead to the release of hot steam, which increases your risk of burns, especially if you place the humidifier close to your face or skin.

Since warm-mist humidifiers have an inbuilt heating element, you do not need to worry about pre-heating the water before pouring it into the water tank in the humidifier.

Child and pet safe

If you have children or pets around your home, hot water can increase the risks of burns or other injuries. Using cold or room temperature water will reduce the risks of injuries.

With this in mind, if you have children or pets, you should also consider investing in a cool-mist humidifier as opposed to a warm-mist humidifier. The cool-mist humidifier will add humidity to your room while at the same time reducing the risks of injuries.

Besides, unless you want to use a warm-mist humidifier with essential oils or decongestants like the Vicks Vaposteam tablets, a cool-mist humidifier is enough to keep your home adequately humidified.

What Happens If You Put Hot Water in a Cool Mist Humidifier?


As earlier stated, it is better to use cold water in a humidifier. If you are using a cool mist humidifier, then you should avoid putting hot water in the humidifier because the humidifier has not been designed to use hot water.

Risk of damage

Most cool mist humidifiers have a filter to prevent the release of dust particles or dirt into the air in your home. Putting how water in a cool mist humidifier can cause thermal damage. The hot water can damage the filter in the humidifier thereby reducing its ability to filter dirt or dust particles from the water.

If you expose the internal components of your cool mist humidifier to boiling water, you also risk thermal damage. Cool mist humidifiers have not been designed with heat-resistant plastic, as such some of the internal parts of the humidifier can get warped or distorted when exposed to hot water.

Leaching of Harmful Chemicals

Exposing plastics that are not heat resistant to hot water can also lead to the leaching of harmful chemicals such as phthalates and BPA.

The chemicals would leach into the water inside the humidifier and be released into the surrounding air in your home. Exposure to these harmful chemicals can affect your health and that of the people living in your home.

As such, using hot water in a cool mist humidifier is not recommended. If you want warm or hot mist, a warm-mist humidifier or a dual-mist humidifier would be a great option because they are heat resistant. Using cold water in your cool-mist humidifier will ensure that the humidifier lasts longer compared to when you use hot water.


When it comes to most humidifiers, if a customer uses the humidifier for something else that differs from its intended purpose, a manufacturer can declare the warranty void.

In the case of water temperature, if you put hot water in a cool mist humidifier and your humidifier gets damaged because of exposure to the high water temperature, your manufacturer will declare your warranty void and refuse to repair or replace the humidifier.

As such, using the correct water temperature protects your product’s warranty and will ensure that you are eligible for a replacement or repair in case you notice any manufacturer-related defect on the humidifier.

What Water do you Put in a Humidifier?

Type of HumidifierWater Temperature
Cool-mistCold or room temperature water (55–72 °F)
Warm-mistCold, room temperature water, or lukewarm water (55–100 °F)
Cool and Warm mist (dual-mist)Cold, room temperature, or warm water (55-72 °F)

Cool-Mist Humidifier

When using a cool-mist humidifier, you should stick to using cold or room temperature water in your humidifier. The temperature of the water should be between 55 to 77 degrees Fahrenheit.

Note that if you opt to use cold water, the water should not be ice cold but the temperature should be slightly below your room temperature.

Ideally, the best water temperature for your cool-mist humidifier is room temperature water. Using room temperature water in your cool-mist humidifier will prevent the risk of filter and humidifier damage.

Warm-mist Humidifier

If you are using a warm-mist humidifier, you can use cold, room temperature, or lukewarm water in your humidifier.

If you have lukewarm distilled water in your home, you can use the water in your warm-mist humidifier. The slightly high temperature of the water will reduce the time that the water will need to heat in the humidifier before being released into the air.

Cool and Warm-Mist Humidifier

If you have a combined cool and warm-mist humidifier aka a dual-mist humidifier, you should stick to using cold or room-temperature water, especially after setting the humidifier on cool-mist.

You are less likely to accidentally use the wrong type of water if you stick to using room-temperature water on your dual-mist humidifier.

Important Considerations

1. Cleaning the Humidifier

Regardless of which type of water you will choose to use in your humidifier, it is important to remember to clean your humidifier regularly.

A dirty humidifier will breed mold and increase your risk of respiratory illnesses. Ensure that you follow the manufacturer’s guidelines on how and when to clean your humidifier.

2. Changing the Water

You should ensure that you change the water in your humidifier regularly. Leaving the water in your humidifier sitting there for a long time will breed harmful microorganisms.

Empty your humidifier when you are not using it and ensure that you clean it before storing it away. You should also change the water in your humidifier daily to reduce the risks of microbial growth.

3. Type of Water

Aside from temperature, the type of water that you use in your humidifier also matters. Distilled water is the best type of water for any humidifier.

Using the right type of water will reduce the risks of mold accumulation and mineral deposit collection in your humidifier.

Recommended read: The right type of water for your humidifier

In Summary

Regardless of which humidifier you are using, the best water temperature for any humidifier is room temperature water. You do not need to pre-heat your water before pouring it into your humidifier’s water tank.

Hot water can damage a cool-mist humidifier and reduce its effectiveness over time. Similarly, if you are using a combined-mist humidifier you should not use hot water because the hot water can damage a combined-mist humidifier, especially if you use the combined-mist humidifier in a cool-mist setting.

Note that the inner parts of your humidifier are sensitive to temperature changes and exposing most humidifiers that have not been made with a heat-resistant material to high temperatures could damage them.


Hot or cold humidifier for congestion

Pouring cold water in a humidifier is better for congestion unless you are using products like Vicks Vaposteam or essential oils that might require you to use warm water.

Whether you use a cold or warm-mist humidifier while you are struggling with congestion, the water will have attained room temperature or your body temperature by the time it makes it down your nasal cavity.

Tap water in humidifier

You should not use tap water in any humidifier as this type of water contains numerous impurities that can damage your humidifier. If you have a water filter in your tap water or a deionizer, you can use the tap water in your humidifier.

What can I add to my humidifier water?

You do not need to add anything to your humidifier water. A humidifier is supposed to improve the relative humidity in your home.

However, if you want to achieve an aroma-therapeutic effect, you should invest in a humidifier that has a diffuser so that you can use essential oils in the humidifier.

Meet the Author

The author is a blogger, interior design and home improvement enthusiast, and researcher, with a passion for helping people improve their homes by creating a calming and beautiful environment. Check out the about author page to learn more about her work