Purified Water vs Distilled Water For Humidifiers: What’s The Difference?

When it comes to adding water to a humidifier, many people get confused. There are a few types of water, but they don’t know which one is better? 

A lot of people understand that tap water is not a great option, but they don’t know the difference between purified water and distilled water.

While purified water gets rid of most impurities, distilled water is still a better choice since the purified water may contain a trace of dissolved minerals and microbes that can clog the humidifier and produce white dust in the long run.

This post will explore what exactly purified water and distilled water are and compare them from different aspects. 

In most cases, adding purified water to a humidifier is fine, but you will understand why distilled water could be even better by reading this post.

What is purified water?

As its name suggests, purified water is the water that is been filtered to remove most of the impurities. People can make it from tap water or groundwater by installing a water purifying system or buying it from stores.

The impurities that have been gotten rid of often include bacteria, fungi, certain minerals, and algae. Water classified as pure water should remove 99% of contaminants.

With the advancement of technologies, you can get purified water in different ways. The common purifying processes include sedimentation, disinfection, coagulation, and filtration. Reverse osmosis is a popular technology for making purified water, and some systems also use the distillation method.

What is distilled water?

Sometimes, the dividing line between purified water and distilled water is blurred, and many people think distilled water is a type of purified water.

Distilled water is the water you get through the distillation process. When water is boiled, it turns to be water vapor. When the water vapor cools down, it will turn to be the distilled water you need. 

Distilled water doesn’t contain minerals, harmful chemicals, bacteria, and other impurities. It is so pure that many humidifier manufacturers often suggest customers use distilled water in the water tank.

Purified water vs. distilled water: which one is better for humidifiers?

purified water vs distilled water

After perusing what I mentioned above, you may think purified water and distilled water are similar. Yes, they are. But you still can tell some differences while using them for humidifiers.


You can get these two types of water online or in local stores. The selling price doesn’t have significant differences. Or you can make them at home. 

There are many ways to make distilled water at home, but using a water distiller is the most straightforward, even though it can cost a few hundred dollars. Otherwise, you can collect the distilled water by making use of the simple appliances already in your kitchen. 

To get purified water at home, you should install a water purifying system and replace the filters regularly. The upfront cost could be much higher, but it is acceptable, considering it can serve you and your family for so many years.

However, installing a water purifying system is not necessary if the tap water in your area is suitable for drinking, and you only plan to use purified or distilled water for a humidifier.

Easy to clean

When you add tap water to a humidifier, it will accumulate scale and promote mold growth in the reservoir, making it hard to clean.

Using distilled water or purified water is much better for those who struggle to commit to thorough cleanings.

When compared distilled water with purified water, distilled water has better performance in keeping the water tank clean because distilled water doesn’t contain any minerals. Therefore, almost no scale will form in the base and tank. 

Purified water removes most minerals, but some dissolved minerals are left that could settle in the reservoir and become an annoyance later.

Effect on humidifier’s lifespan

Humidifiers can malfunction at some point, and the causes often boil down to clogs. When the device is clogged, the parts can get overheated, and the diaphragm can’t vibrate to break down the water. 

The mineral buildup is the main culprit of these clogs. Therefore, the less mineral the water has, the better the water is. Therefore, distilled water is an absolute winner in this round as purified water has some minerals.

By insisting on using distilled water, the humidifier can last longer than the one that uses purified water.

Health risks

Drinking purified water could be beneficial for our health. It could be even better than distilled water since it contains some beneficial minerals. Nevertheless, it is another story when it comes to using it in a humidifier.

The mineral deposits caused by purified water could transform into white dust in the air. While white dust is not toxic, when you inhale it, it may cause infections in the lungs.

If you don’t clean the tank regularly, the mineral buildup could become the peri dish for molds. Then these molds can disperse into the air and hunt for the new residence – your body.

Again, distilled water doesn’t contain minerals, so it is free of these adverse effects. 


Distilled water can use more energy because you have to heat the pot or other containers to make the evaporation happen. Purified water is filtered by various filters or other devices which consume less energy. 

Purified water vs. distilled water for humidifiers: conclusion 

Purified water and distilled water are two types of water people like to add to a humidifier. Honestly, they are pretty similar as they are the two cleanest water in our life. 

However, as purified water contains some minerals, it can accumulate mineral deposits in the base and tank, increasing the time for cleaning and shortening the humidifier’s lifespan. 

So in terms of the water for humidifiers, distilled water is the winner compared to purified water.

Anyway, using purified water is still better than using tap water. Therefore, you don’t need to worry too much if the distilled water is unavailable. The appliance will work smoothly as long as you clean and disinfect it frequently.  

About The Author

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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 dozens of products in person, like 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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