Optimal indoor air quality is always one humidifier purchase away. But when it comes to the two types of cool mist humidifiers, the choice between an ultrasonic and evaporative humidifier can leave you scratching your head.

Picture this: a crisp winter morning, you wake up, and the air feels dryer than a desert. You know you need a humidifier, but which one? You should never make this decision based on aesthetics or brand names alone. 

The choice between an ultrasonic and an evaporative humidifier requires that you gain a clear understanding of the science and mechanics behind these machines to understand how they can transform your indoor living space.

So join me below as I take you on a journey through a realm of evaporation and ultrasonic waves, and we aim to settle the question of which is the best cool mist humidifier type once and for all.

What’s The Difference Between Ultrasonic and Evaporative Humidifiers?

Ultrasonic and evaporative humidifiers use distinct mechanisms for adding moisture to the air. Ultrasonic humidifiers employ high-frequency vibrations to generate a fine mist of water droplets that are released into the surrounding air, evaporative humidifiers blow air through a wet wick or filter, promoting the evaporation of moisture into the environment.

While both contribute to improved indoor air quality, it’s worth noting that each type comes with its own set of considerations.

Let’s explore a little deeper.

Ultrasonic vs Evaporative Humidifiers

Ultrasonic Humidifiers

Ultrasonic Humidifier

An ultrasonic humidifier increases the humidity level in a room by releasing tiny water droplets into the air. It operates through a system consisting of a ceramic diaphragm that vibrates at an ultrasonic frequency. This diaphragm extracts water from the reservoir and transforms it into fine droplets that are then dispersed into the air by a small fan.

It’s worth noting that all ultrasonic humidifiers are cool mist. The technology is not available for warm mist humidifiers, and the water droplets ultrasonic humidifiers produce are typically at room temperature.


  1. Requires minimal maintenance for cleaning, as well as infrequent internal servicing.
  2. Ultrasonic humidifiers are quieter than evaporative ones, operating with minimal noise; both the fan and ceramic diaphragm are quiet when releasing water into the air. The ultrasonic vibrations produce virtually no noise at all.
  3. Eliminates the risk of burns, as the water temperature remains either room temperature or cooler.


  1. There is a higher risk of bacterial or germ contamination in the water unless the reservoir is regularly cleaned as instructed.
  2. Ultrasonic humidifiers tend to be among the higher-priced options on the market.
  3. Older models (more than five years old) may emit white dust that can exacerbate respiratory issues and lead to throat irritation. Newer models have incorporated special filters to address this issue, but it can also be prevented by using only distilled water in your ultrasonic humidifier.

Evaporative Humidifiers

Evaporative Humidifier

An evaporative humidifier is designed to increase humidity levels by drawing in dry air through a wick or filter that is saturated with water. The dry air passes over the wet surface of the wick, causing the water to evaporate into the air, effectively raising the humidity in the surrounding area. 


  1. Low risk of bacterial or germ contamination in the water due to the natural evaporation process. However, it’s still recommended to clean the wick or filter regularly.
  2. Evaporative humidifiers are generally less expensive than ultrasonic models, making them an economical choice for many households.
  3. Since evaporative humidifiers work without a heating element, they have a lower environmental impact and are considered the more eco-friendly of the two types of humidifiers.


  1. Evaporative models use more water compared to ultrasonic models. This is because water is continuously evaporating from the wick or filter, which may result in more frequent refilling of the water tank.
  2. Can be slightly noisier due to the fan required to draw air through the wick or filter. However, modern models still use a fan but employ quieter technologies.
  3. Evaporative humidifiers tend to have more limited control over humidity levels. They work based on the natural evaporation process, which means they can only add moisture up to a certain point, and they may struggle to achieve higher humidity levels in extremely dry environments.
Deciding Between Evaporative And Ultrasonic Humidifiers

Clearing the Mist: Deciding Between Evaporative And Ultrasonic Humidifiers

When it comes to choosing a humidifier, there’s no definitive right or wrong choice. They all serve the fundamental purpose of adding moisture to the air, contributing to a healthier environment.

To make the best decision, delve into the specifics of each device and how they’re controlled, ensuring they align with your needs.

While choosing between an ultrasonic or evaporative humidifier can initially seem daunting, you must base the decision on how the underlying science and mechanics of each device can transform your living spaces.

Both will actively contribute to improved air quality, but it’s important to note that not all units will align with your noise and energy consumption preferences.

So whether you opt for the ultrasonic humidifier’s minimal maintenance and quiet operation or the evaporative’s affordability and eco-friendly operation, take your time to ensure you are armed with the knowledge you need to confidently select the best humidifier for your home.