Informational Guide

Comparing Humidifiers Vs Diffusers

If you want more water and moisture in your home, bring home the humidifier. If you want fragrance in the air, bring home the diffuser.

by Josh M

Are diffusers and humidifiers the same? Both diffusers and humidifiers bring a welcoming, calm, and comfortable presence to your home. However, each device does something different. Diffusers add fragrance to the air, while humidifiers add moisture (think water) to the air.

Our guide will help you choose between the diffuser and humidifier for your home.

Blue & White Ceramic Type Humidifier

Oil diffusers work to create a spa-like environment in your home with calming fragrances that make it easier to breathe.
Adding Essential Oil to A Brown and White Diffuser

  • Nebulizing diffusers
    A nebulizing diffuser works by sending out an oil mist into the room. These diffusers are cool because they do not use heat or water, so they are easy for busy homeowners.
  • Ultrasonic or humidifying diffusers
    Ultrasonic diffusers will also send out an oil mist, but this mist is water-based. The essential oil has to have water added to the concoction in order for it to work. The benefit here is that water is put back into the air.
  • Evaporative diffusers
    An evaporative diffuser uses a fan and will evaporate the oil so that it can move into the air through a gas form. This works well for people who are only interested in the scent of the essential oil.
  • Heat or electric diffusers
    A heat diffuser requires heat (typically through electricity by being plugged in). This is a silent machine and less common. These devices can get too hot to be in rooms with pets or children, so there are some safety concerns to be aware of.

Pros & Cons of Diffusers

What We Like
  • Fragrant aromatic scent
  • Fun light features on some devices
  • Zen, calming presence created with essential oils
  • Medicinal benefits of essential oils diffused in home
  • Low maintenance
What We Don’t Like
  • Lack of moisture in the air
  • Will not help with congestion in sinuses
  • Small surface area coverage

What Does a Humidifier Do?

A humidifier is responsible for adding moisture back into the air and increasing the overall humidity level in the room. Many people who have allergies and sinus problems benefit from humidifiers because the extra moisture in the air coats their airways and makes breathing easier.

Humidifiers also can help to kill viruses and disinfect the air. These devices can also be purchased with a hot mist option for a more luxurious, spa-like feel. A hot mist humidifier will also warm the air and can make a room feel warmer.

Humidifiers, however, do not add fragrance to the atmosphere. There are combination units that can be purchased, but humidifiers on their own only add water to the air.

Pros & Cons of Humidifiers

What We Like
  • Comfortable humidity levels
  • Helps with sinus congestion
  • Helps with allergies
  • Better sleep
  • Helps to kill viruses
What We Don’t Like
  • No fragrance
  • White dust
  • Requires weekly cleaning
Dehumidifier with Essential Oils

What Do Humidifiers & Diffusers Have in Common?

Moisture Control

Both humidifiers and diffusers can contribute to moisture control in a large room or entire home. However, humidifiers are designed specifically to take care of moisture by adding moisture back into the environment. Diffusers can add moisture but in smaller quantities and only if the diffuser is an ultrasonic/humidifying diffuser.

Disinfecting Benefits

Humidifiers do not kill germs, but they will help reduce them because higher humidity levels can work to kill viruses. Diffusers can also disinfect if a disinfecting essential oil is used, such as eucalyptus, lavender, geranium, lemon, clove, or thyme. Be sure to check for pet-safe essential oils before loading up your diffuser.

Easy to use design

Most modern humidifiers and diffusers use easy-to-use designs that make operation a breeze. Between auto shut-off buttons, mist speed and volume controls, timer options, and accessible water or essential oil refill valves, it is easy to add one of these devices to your home.

Humidifiers Vs. Diffusers: Key Differences Explained

Choosing a humidifier or diffuser for your home is a personal choice. We want to help you break down the differences. The primary difference between the two is that the humidifier adds moisture back into the air, and the diffuser adds essential oils into the air.

Volume / Area covered

Consider the room that you want to place your diffuser or humidifier in. Make sure that the device you choose can cover the area in full. For example: selecting a diffuser that covers 108 square feet but placing it in a 350 square foot room will not give you the aromatic benefits that you want.

Make sure the device can handle the square footage of the room you want to place it in.

Air quality / Air Cycles per Hour

The air quality in your home will improve most with a humidifier that increases the moisture level. A diffuser will provide an aromatic quality to your home. The amount of air cycles per hour that a humidifier or diffuser can complete depends on the size and type of machine.

We recommend reviewing each individual machine to make sure you are getting several air cycles per hour. The larger the device, typically, the more powerful the air cycles per hour.

Scent Strength

Humidifiers do not add a scent to the air because their goal is to build up the moisture levels in the room. Diffusers are the better choice when it comes to scent and fragrance in your home.

Healing Properties

When it comes to healing properties, both devices can help. For sinus problems and allergy problems such as asthma, we recommend a humidifier. These can help moisturize the person’s airway. Diffusers are helpful for bedtime relaxation (think lavender) or air disinfectant (think eucalyptus and geranium).

Mood Influencing

Diffusers win when it comes to mood influencing. The essential oils used with a diffuser help bring a spa-like aromatic quality to your home. Lavender, for example, has been known to help with sleep and anxiety, while peppermint has been known to help lower frustration and fatigue.

Lifespan of Device

Most humidifiers and diffusers last anywhere from five to fifteen years. We recommend reviewing the warranty for each device so that you are covered in the case of a part malfunctioning.

Price Range

Diffusers tend to cost less than humidifiers. Consider your price range before making a purchasing decision. Cost increases based on the coverage area of the diffuser/humidifier and the additional features included.

Are There Humidifiers That Are Also Diffusers?

Yes, there are aromatherapy humidifier/diffuser combinations that provide both a sweet, perfumed scent and add moisture to the air. These combinations are often called aromatic ultrasonic humidifiers and have numerous features.

They work by using both water and essential oils through a mist that is sent out into the room. The water slowly brings up the humidity level, and the oil adds a delightful scent to the space. These devices often need to be run for more extended periods of time in order to properly humidify the room and add fragrance.

People Also Ask (FAQ)

Can you use a diffuser as a humidifier for plants?

No, you cannot use a diffuser as a humidifier for plants, but you can use a humidifier. Place a humidifier in the same room as your plants, and they will benefit from the excess moisture.

Can you run a humidifier and diffuser at the same time?

Yes. You can run a humidifier and diffuser at the same time. These devices do two different things, and it is not a problem to run them simultaneously. We recommend keeping them at least two feet apart so that they can properly circulate moisture and fragrance throughout the home.

Can you sleep with a diffuser on?

Yes, you can sleep with a diffuser on. However, if the diffuser does not have an automatic shut-off setting, then it may wake you up in the middle of the night with a flashing light or sound indicating that it needs to be filled.

Do oil diffusers help you sleep?

This varies by person. Some people sleep better when they breathe in calming fragrances such as lavender or eucalyptus, but others are not affected by the scents.


Purchasing a humidifier or a diffuser can help moisturize the air in your home or provide a soothing, fragrant environment.

If you want more water and moisture in your home, bring home the humidifier.

If you want fragrance in the air, bring home the diffuser.

Use both machines together for the optimal home spa experience.

Last Updated on December 20, 2022

Josh M

My name is Josh and I am obsessed with the HVAC industry. I created this website to help HVAC techs of all levels get the best out of their heating & cooling systems. I have spent thousands of hours studying air conditioners, heaters and home air products so you can learn & buy with confidence. Learn more about the team here.