Can You Use a Diffuser as a Humidifier? Facts Need to Know

Last Updated on March 14, 2024

Can you use a diffuser as a humidifier? This is a thought that has crossed most of the diffuser owners’ minds at least once. It is actually a valid question, as diffusers and humidifiers both look and work kind of the same. 

The answer to the question is yes! In some cases, you can use a diffuser as a humidifier. But that being said, the output of a diffuser won’t be as good as a humidifier for some obvious reasons, which include the tank size, run time, etc.  

In this guide, we have covered a few essential factors that you need to know if you are thinking of using a diffuser to add moisture to the air

Check it out! 

A Diffuser as Humidifier – How Well Does It Actually Work? 

Even though the humidifier and diffuser look the same, they aren’t! There are a few significant differences between these two things. 

The primary goal of a diffuser is to create a fine mist of essential oils and disperse it. Diffusers make the air aromatic but moisten the air very poorly. 

Whereas humidifiers are designed to transform water into moisture and spread it; therefore, air absorbs the moisture. 

So coming to the question, how well does a diffuser work as a humidifier?

Not very good! We have pointed out two major reasons why diffusers aren’t an alternative to humidifiers. 

Diffuser vs Humidifier

The first one is, diffusers come with a very small water reservoir. Most diffuser tanks can only contain a cup of water, whereas humidifier tanks can contain up to a half gallon of water. 

Due to the less capacity, you will have to keep refilling the water several times a day if you use a diffuser to moisten the air. 

On the other hand, diffusers are made to run for up to 20-40 minutes in one go. They are designed to be used a couple of times a day. And that is a big barrier if you want to use a diffuser as a humidifier. 

Humidifiers can run for up to 5 – 16 hours straight. You can’t do that with a diffuser, as it will break down in no time. 

Even if you get a large water tank in the diffuser and get the chance to run it for straight 6 hours, the diffuser will still not be able to moisturize the air as much as a humidifier. And that is due to the difference in the mechanism. Both of these work differently. 

A Test on the Humidifying Ability of an Ultrasonic Diffuser

An experiment has been conducted to see how effectively a diffuser can humidify the air. Here’s how it was conducted. 

The tester used an ultrasonic diffuser and a cool mist humidifier of the same size. First, the tester checked the humidity of the room, which was 22%. 


Then he ran the humidifier for straight 30 minutes in a small room, and after 30 minutes the humidity level increased to 26%. 

To take the humidity level to normal the tester waited for a day. And the next day the room’s humidity level was 23%. After running the diffuser for 30-minute, the humidity level increased to 24%. 

The humidifier increased the humidity level by 4%, whereas a diffuser of the same size could only increase by 1%. Therefore, even though you can use a diffuser as a humidifier, it wouldn’t be effective. 

Having that said, you can effectively use diffusers as humidifiers for indoor plants, discussed broadly in the coming section. 

Can You Use a Diffuser as Humidifier for Indoor Plants?

Most indoor plants require moisture in order to grow properly, on average, mature plants require 50% to 60% humidity in the air. The requirement actually depends on the type and size of the plant. Some tropical plants need higher humidity levels, as high as 90%.

That being said, there are some plants that don’t require much humidity, they can grow at a humidity level as low as 10%. Cacti, Succulents, etc. are plants that require very low to no moisture at all. 

If the room where you kept the plants is very small and if you have a bunch of indoor plants that require a medium humidity level (50% – 60%), a diffuser should work just fine.

But you will have to make sure that you run the diffuser next to the plants. And also keep in mind that, if the room is big, the diffuser won’t be able to moisturize the air. The room needs to be very small. 

Can You Use A Diffuser As Humidifier For Indoor Plants

Or you can make a glass cabinet and put the small plants there, it will work like a greenhouse. If you run the diffuser inside the glass cabinet, you will be able to lock in more moisture. Plus, plants inside a glass cabinet will look very aesthetic as well. 

And if the room is big, and you can’t make a glass compartment, you better use a big humidifier. 

Is It Safe to Diffuse Essential Oils Near the Plants?

If you are wondering if you could diffuse essential oil near the plants, know that it’s totally fine. It is even better for plants. Some essential oils contain beneficial properties for plants and are also good for human health.

Neem, tea tree and Citronella essential oils come with properties that prevent the growth of insects and slowly repel them. Some oils come with antifungal properties such as cinnamon oil, which protects the plant from damaging organisms.

Essential oil doesn’t come with enough chemicals to harm the plant. That being said, since plants filter the air, if you diffuse too much essential oil, then the plants might counteract.

Frequently Asked Questions 

  1. Can a diffuser work as a humidifier? 

Yes! A diffuser can only work well as a humidifier if the room is very small and the humidity level requirement is low. 

  1. Does an oil diffuser count as a humidifier? 

Essential oil diffusers add a very low amount of moisture to the air but still, they can’t be counted as a humidifier. That’s because they can’t run as long as humidifiers and nor do they have a large water holding capacity. 

  1. Do diffusers add humidity to the air? 

Yes, diffusers do add humidity to the air but a very low amount compared to humidifiers. 

  1. Can you put just water in a diffuser? 

Yes, you can just put water in a diffuser, it will add moisture to the air. But since they have a very small water tank, you will need to keep refilling the tank several times a day. 

  1. Can a diffuser be used as a humidifier when sick? 

If someone is sick and needs humidity in the air, then an actual humidifier is the way to go. Diffusers add a very low amount of moisture to the air. 

  1. What is better, a humidifier or a diffuser? 

It depends on your needs. Both of them are good in their own field. If you want to humidify the air, then a humidifier would be better. And if you want to diffuse essential oil to have an aromatic effect in the room, then a diffuser is better. 

  1. Can I use essential oil in the humidifier?

Diffusers come with a plastic water tank that is compatible with essential oils, and humidifiers lack that. The plastic tank found in humidifiers isn’t compatible with essential oil; as a result, the tank gets damaged pretty soon. 


So, can you use a diffuser as a humidifier? For plants, definitely! But not for humans at all. And a diffuser is an absolute no-go for a big room.

In terms of humidifying, diffusers aren’t even close to humidifiers, and that’s pretty obvious. Therefore, it would be best if you stick to humidifiers when it comes down to moisturizing the air. 

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Paul M Walker

I, Paul M Walker, am the founder and the author of this little site you are currently on. I work to provide readers with no-fuss and easy-to-follow solutions regarding common air purifier and humidifier problems.

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