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Cool Mist vs. Warm Mist Humidifier for Sinus Problems

Cool Mist vs. Warm Mist Humidifier for Sinus Problems: Know The Better Choice

The cold and dry winter months often mean agony for many of us. Nasal congestion, cough, asthma, these respiratory problems spring up during this period. We tend to be susceptible to sinus problems more than usual. 

More and more people know humidifiers help ease sinus issues, however, they aren’t sure which is better cool mist and warm mist humidifiers. 

If you have the same question to ask, you have come to the right place. This post will explain why humidifiers can help with the sinus and the factors you need to take into account when choosing a humidifier for this condition. Then you will understand which type of humidifier is better for sinus infection.

Understand cool mist humidifiers and warm mist humidifiers

cool mist humidifiers and warm mist humidifiers

First, it is important to understand the similarities and differences between cool mist and warm mist humidifiers. Warm mist humidifiers work on the same principle, whereas cool mist humidifiers work in various ways. 

Warm mist humidifier

A warm mist humidifier also refers to vaporizers or some ultrasonic humidifiers that embrace a heating element. It adds indoor humidity by boiling the water with heating elements. The hot water turns to warm water vapor in the air through an evaporation process or vibration. It will warm the room a bit which you can barely feel. 

Cool mist humidifier

Actually, there are three types of cool mist humidifiers. So I want to introduce them separately. But the main difference between warm and cool mist humidifiers is that they expel mist with the ambient temperature since they don’t employ any heating element. 

Ultrasonic humidifier

The ultrasonic humidifier is the most common type of humidifier these days. It breaks down the water into tiny moisture particles by a membrane through high-frequency vibration. The vibration is inaudible to us, so we feel it is very quiet. 

Evaporative humidifier

evaporative humidifier

Different from ultrasonic units, evaporative humidifiers utilize a fan to boost the evaporation process. When the air gets into the device, it will go through the wick, and then water in the wick will get into the air as vapor. The vapor is invisible in most cases.

Impeller humidifier

The impeller humidifier is not as popular as other types. It comes with a disc, which can fling the water onto the diffuser. This diffuser will then break the water into water droplets. 

How do humidifiers relieve sinus problems?

Until now, we already have had a basic idea about how warm and cool mist functions, it is time to figure out why people can use humidifiers to ease sinus infection. 

How do sinuses work?

Structure of Sinuses and how they work

Our sinuses act as the filter of the air we inhale. They can filter out the bacteria, dirt, and other impurities and warm and humidify the air while protecting our lungs from getting infections. 

The mucus membrane will constantly produce mucus. Mucus will go through sinuses and take away the water that has been filtered out and drain to our throat. Then we will swallow mucus along with these harmful substances. 

What will happen to the sinus when the humidity level is too low 

When the air gets dry, the mucus membrane will react to produce more mucus to humidify the air as usual. However, as the sinuses are dry, the mucus will become thicker, which is hard to flow out and blocked inside. 

That’s why you often get nasal congestion and runny nose in winter or arid regions. In addition, as bacteria, fungi, and pollens can’t be carried away, our bodies will be more susceptible to allergies, asthma, and lung infections.

Since humidifiers work to increase humidity levels, they can help alleviate the conditions caused by dry air.

Will warm mist or cool mist make any difference?

Even though they work on different principles, warm and cool mist humidifiers don’t make any visible difference in humidifying the air. So these two types of humidifiers will have the same effect on relieving conditions caused by humidity. 

As we said above, sinuses can warm the air, meaning that no matter which temperature the air is, your sinuses will adjust the temperature automatically. The air will get the same temperature before getting into the lower airways. Let along the warm mist will cool down a lot before getting into your nasal passages. 

So regarding the effect on sinus problems, warm mist and cool mist humidifiers shouldn’t vary too much. 

Doctor Julie Baughn has mentioned that heated air may not help with cold symptoms, whereas a study showed that heated air might enhance mucociliary transport. This suggests that more research is needed.

Cool mist vs. warm mist humidifier for sinus problems: factors to consider

When comparing a cool mist humidifier with a warm mist humidifier, you shouldn’t only consider the effect on easing sinusitis, but many other things need to be factored in.


Safety is always the top priority for everyone using a humidifier. It is even more critical when you have kids and pets around.

A cool mist humidifier is a better choice under this circumstance because your baby and a furry friend will never get burns caused by hot water in the water tank. You know how curious they are.


Cool mist ultrasonic humidifiers and whole-house humidifiers could be your best bet if noise is your major concern. This is due to the fact that we can’t hear the high-frequency vibration, and the whole-house humidifier is often located in the basement. 

Warm mist humidifiers use heating elements to boil water, making a bubbling noise. Evaporative humidifiers utilize a fan to blow out the wet air. Therefore, these two types of humidifiers may not be able to meet your needs.

evaporative humidifier fan

Note that dogs’ and cats’ sense of hearing is much keener than humen. They may hear the sound caused by vibration. It is advisable to observe their behavior if you get an ultrasonic one.

Cleaning requirement 

Humidifiers help ease sinus issues, but they can lead to adverse effects if they aren’t well maintained. The bacteria, mold, and other germs in the tank can get into the air with water vapor, which will pose risks to your health. 

In this regard, warm mist humidifiers are better than cool mist models since a majority of microorganisms will be killed by boiling. 

Anyway, you should change out the standing water every day and clean the water tank every three days regardless of which type of humidifier you have. If you use an evaporative or furnace model, you should also regularly replace the filter.


The classic vaporizer has the lowest price tag; however, there is not much difference between modern warm mist units and cool mist units. 


Is a warm or cool mist humidifier better for the sinuses? We can’t find a concrete answer to this question. From what we found up till now, there aren’t enough studies to show the difference in effect on easing sinus problems between warm and cool mist humidifiers.

So the decision you make would be dependent on other factors. For example, if you have children and pets at home, cool mist humidifiers are safer, while warm mist humidifiers are better if you’re in doubt about regular cleaning.

Vaporizers are the most affordable type of humidifier if you are on a budget.

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Liz Yang is the founder of Airsmartly. She has been working at home for a few years and realizes that the performance of the HVAC system plays such an important role in our life. She has tested more than 150 products in person, including humidifiers, air purifiers, dehumidifiers, and ACs, and wants to share tips about using or troubleshooting these products with you. Her uncle is an HVAC expert with over 30 years of experience in the field, and often offers assistance when she is unsure how to handle a situation. He is also in charge of reviewing the articles on this site.

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