Humidifier Vs Diffuser – Which Is The Better Choice For Homes?

Due to my breathing issues, I use a humidifier and diffuser in my home. One improves my home’s air quality by adding moisture to it and the other uses essential oils to add a fresh fragrance to the air

Which unit does which job, though? I have been asked countless times about which option is better and why.

So, in this guide, I’ll explain what the difference between a humidifier and a diffuser is and when you should use each device.

Humidifiers Vs Diffusers: Key Differences Explained

Although they seem similar, humidifiers and diffusers differ in many ways. Here’s my breakdown of the most significant differences between them.

Volume / Area covered

Diffusers are generally smaller and can’t cover very large areas. I use a very small unit, for example — just big enough for my bedroom. Humidifiers come in a wide variety of sizes, from small personal units to huge whole-house humidifiers, and can humidify even large rooms and buildings.

That said, there’s a range of sizes available for both machines. Pay attention to a diffuser’s or humidifier’s volume to match it to the size of your living space and get the most benefits.

Air quality

Essential oil diffusers do not generally improve air quality — they only add scents and fragrances into the air. Although some essential oils, like eucalyptus, have antibacterial properties, diffusers aren’t designed to enhance air quality.

Humidifiers, on the other hand, can improve the quality of indoor air but adding moisture to it. A humidity level between 30-50% can moisturize your airways, destroy airborne viruses, and reduce asthma and allergy symptoms. I can breathe much easier with properly humidified air.

Scent Strength

I love my diffuser because it adds strong, lovely scents to my home. These machines are purpose-built to dispense fragrant essential oils into the air.

Basic humidifiers don’t produce scents because their goal is to build up the moisture level in dry air. In fact, any scents (good or bad) coming from your humidifier could be a sign of operational problems.

Health Benefits

Both essential oil diffusers and humidifiers can provide health benefits — only in different ways.

A humidifier can bring you significant health benefits, including:

  • Reducing coughing and congestion
  • Providing relief for asthma and sinus problems
  • Keeping your skin and hair moisturized
  • Destroying airborne viral particles (1)
  • Relieving snoring (my wife really appreciates this benefit)

Meanwhile, you’re like to see these diffuser benefits:

  • Aiding relaxation and feelings of calmness
  • Reducing anxiety
  • Promoting peaceful sleep
  • Improving mood
  • Reducing congestion and inflammation
  • Providing relief for skin conditions

Mood Influencing

Diffusers win when it comes to influencing your mood. The essential oils used with a diffuser create a spa-like aromatic environment in your home. My unit can really improve your mood, depending on the essential oil I use.

A humidifier only emits a fine mist or water vapor into dry air to increase moisture levels. They don’t do anything in particular to improve your mood. That said, being able to breathe easier does make me a lot happier!

Device size

Diffusers and humidifiers are both available in many sizes for use in different rooms. Humidifiers tend to be larger, though, since boosting the humidity in your home is a more intensive process than wafting scents around.

Let me illustrate this. A diffuser’s water reservoir holds on average around 1-2 cups of water. An average humidifier tank, on the other hand, has a volume of around one gallon.

Device Lifespan

Most humidifiers and diffusers can last anywhere from 5 to 15 years. Your device’s lifespan will depend greatly on its brand, build quality, and how well you maintain it.

With proper cleaning and maintenance, you can enjoy the benefits of a high-quality diffuser or humidifier for years to come. I recommend investing in a good unit because the cheapest available device can break within months or weeks.

Price Range

When it comes to humidifier vs. diffuser price, diffusers tend to cost less than humidifiers. They are generally smaller and simpler devices, which keeps their price low.

The retail price depends entirely on the unit’s size, volume, and additional features, though. I’ve seen a high-end luxury essential oil diffuser with all possible bells and whistles costing triple or more than what a basic desktop cool mist humidifier does.

Running Costs

Humidifiers and diffusers both need electricity to run, which will add to your monthly utility bills. However, humidifiers consume more energy on average than diffusers.

Humidifiers tend to be larger and require regular filter changes, which adds to their running costs. If you want to minimize your device’s running costs, look for Energy Star or other energy efficiency labels on the box — or my favorite, ultrasonic humidifiers.


Humidifiers need more maintenance than diffusers. That said, you should clean both units regularly — I recommend doing it once a day — to prevent mold and bacterial growth in the water tank. The cleaning process is similar between both devices.

Humidifiers may also require you to replace filters or other consumable parts to maintain their effectiveness. It’s not a huge task, but still, more than you need to do with most diffusers.

Potential Hazards

Both kinds of devices have water tanks that could leak or spill, causing water damage. If you don’t clean the tanks regularly, they could also get moldy and introduce spores or bacteria to the air in your home.

Humidifiers can increase the humidity level in your home too much. Excessive moisture in the air can promote the growth of mold, bacteria, and dust mites that could cause respiratory issues. I accidentally got my curtains moldy with my first humidifier.

On the other hand, if your diffuser is too powerful for a small room, the overwhelming scent could cause headaches or breathing issues. Additionally, you must be careful not to use essential oils that could bother allergy sufferers. (2)

What Do Humidifiers & Diffusers Have in Common?

Despite their differences, there are things that humidifiers and diffusers share with each other. I’ll detail the similarities between them below.

Moisture Control

Both a humidifier and a diffuser can add moisture to indoor air since they use water vapor. However, humidifiers are designed specifically to boost moisture levels and will be far more efficient. Diffusers add moisture only if the diffuser is an ultrasonic/humidifying diffuser.

Disinfecting Benefits

Humidifiers can reduce the levels of viral particles because higher humidity levels make it difficult for viruses to survive. Disinfecting essential oils, such as eucalyptus, lavender, geranium, lemon, clove, or thyme, can also destroy certain viruses when dispensed through a diffuser. (3)

That said, neither device is intended to clean indoor air. I recommend looking into air purifiers to clean your home air.

Easy-to-use design

Most modern diffusers and humidifiers have easy-to-use designs that make operating them a breeze. Between auto shut-off functions, 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.

Blue & White Ceramic Type Humidifier

What Does an Oil Diffuser Do?

Oil diffusers work to create a spa-like home environment with calming fragrances that can make it easier to breathe. Different types of diffusers emit essential oils in different ways.

Adding Essential Oil to A Brown and White Diffuser
  • Nebulizing diffusers
    A nebulizing diffuser forces a pressurized air stream through tubes containing essential oil, turning it into an oil mist that spreads into the room. They create a cool mist because they do not use heat or water, so they are easy for busy homeowners.
  • Ultrasonic or humidifying diffusers
    Ultrasonic diffusers send out a water-based oil mist. The diffuser has a vibrating plate that breaks the oil-laden water into a fine mist. These machines can boost air moisture levels in small amounts.
  • Evaporative diffusers
    An evaporative diffuser uses a fan to evaporate essential oils into the air in gas form. This works well for people who are only interested in the scent of the essential oil (like me).
  • Heat or electric diffusers
    A heat diffuser uses a heat source to warm and evaporate essential oils. This kind of silent unit is less common. These devices can get too hot to be in rooms with children, so there are some safety concerns to be aware of.

Pros & Cons of Diffusers

What I Like

  • Fragrant aromatic scent
  • Fun light features on some devices
  • Calming Zen presence created with essential oils
  • Essential oils can have health and aromatherapy benefits
  • Low maintenance

What We Don’t Like

  • Do not add moisture to dry air
  • Will not help with congestion in sinuses
  • Small area coverage
Adding Essential Oil to A Brown and White Diffuser

What Does a Humidifier Do?

A humidifier adds moisture to dry air and increases the overall humidity level in the room. These devices are generally split into warm mist and cool mist humidifiers.

Warm mist humidifiers boil water with a heating element to produce steam vapor. They can be very effective at humidifying a room but come with similar safety concerns as heat diffusers.

The most popular types of humidifiers are cool mist humidifiers, such as ultrasonic humidifiers and evaporative humidifiers. Ultrasonic humidifiers are my favorites and work like ultrasonic diffusers — using a vibrating diaphragm to create water droplets. Evaporative humidifiers have a fan that blows air over a wet wicking filter to introduce moisture to the space.

Pros & Cons of Humidifiers

What I Like

  • Comfortable humidity levels
  • Helps with sinus congestion
  • Helps with allergies
  • Better sleep
  • Helps reduce virus levels
  • Healthier plants and wood furniture

What I Don’t Like

  • No fragrance
  • White dust from hard water
  • Requires daily cleaning
Dehumidifier with Essential Oils

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.

This kind of cool mist humidifier dispenses both water and essential oils in the mist it creates. The water slowly brings up the humidity level, and the oil adds a delightful scent to the space. Personally, I’m not a huge fan of these units as they need to be run for a longer time to have a noticeable effect.

Some humidifiers also have specific containers for essential oils. As the humidifier runs, it also introduces oil into the air.

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. Diffusers don’t increase air moisture enough to benefit plants.

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

Yes, you can run a humidifier and diffuser at the same time. I recommend keeping them at least two feet apart so that they don’t interfere with each other.

Can you sleep with a diffuser on?

Yes, you can sleep with a diffuser on. However, I recommend purchasing a unit with an automatic shut-off setting in case the device runs out of oil.

Do oil diffusers help you sleep?

An essential oil diffuser can help you sleep. Some people sleep better when they breathe in calming fragrances, such as lavender or eucalyptus, but others are not affected by the scents.


Humidifiers and diffusers both help you breathe easy in your home. With my guide, you now know which unit is right for you.

If you want more moisture in your home air, choose a humidifier. But if it’s a calming fragrance you’re after, purchase an essential oil diffuser.

Or, you can do what I did and buy both! Using a humidifier and diffuser together can create an optimal home spa experience.





Josh Mitchell

Josh Mitchell

My name is Josh and I am obsessed with DIY and improving my family home. HVAC topics can be tricky for homeowners so I decided to share my knowledge on the subject. When I am not working on DIY projects, you can find me at the beach or my local coffee shop.