img img
Stay In Touch

Lucky Mag is supported by our readers. When you buy through links on our site, we may earn a commission. Learn more.

What Does a Humidifier Do

By: Sheryl Cannes
Updated on: April 05, 2024

The right humidity levels can moisturize dry skin, keep nasal passages lubricated, reduce static electricity, and help relieve allergy symptoms. In dry climates or homes with allergy or asthma sufferers, a humidifier is a quick fix. There are different types, shapes, and sizes, but what exactly do humidifiers do? And do you need one? We’ve put together the information you need to make that decision.

What Humidifiers Do

Humidifiers release steam or water vapor to add moisture to dry air. Models range from small and simple to whole-house humidifiers that connect to your HVAC. They can come with 24-hour timers, built-in hygrometers, multiple fan speeds, or as a humidifier/air purifier combo. Then, of course, there are models that simply release moisture with no extra features.

Benefits of Humidifiers

There are many reasons you may want or need a humidifier. Their top benefits include:

  • Allergy Relief: Humidity keeps the airways and nasal passages moist. If they dry out, they’re more easily irritated or inflamed by pet dander, pollen, and dust mites.
  • Asthma Relief: Moist air can help ease the air passages, especially if you have a head cold. Humidity levels kept between 30 to 50 percent can loosen phlegm, relieving coughs.
  • Moisturizes Dry Skin and Lips: Dry, itchy skin and lips can be painful and embarrassing. Appropriate humidity levels, in addition to the use of moisturizing products, work to keep skin and lips healthy.
  • Reduces Vocal Cord Irritation: Whether raspy vocal cords come from a cold, allergies, or a dry climate, a humidifier can help. It doesn’t matter if you talk for a living or not. It shouldn’t hurt to use your voice.
  • Reduces Static Electricity: A little shock here and there isn’t a problem, but some electronics are susceptible to damage from static. Nobody likes their clothes to cling to them with static either. The right humidity levels can reduce static’s inconvenient effects.

Types of Humidifiers

At their most basic, humidifiers come in two broad categories—warm-mist humidifiers and cool-mist humidifiers. However, within those two categories, there are several different types.

  • Central Humidifiers: Central humidifiers are whole-house models that connect to your home’s HVAC system. They’re a good option if you live in a dry climate because dryness will always be an ongoing issue.
  • Standalone Whole-House Humidifier: These humidifiers are large enough to humidity an entire house, though they don’t connect to the furnace or air conditioner. They should be located where the air can circulate. Because they’re big, an out-of-the-way corner is often a preferred location. They also come in models with faux paneling to hide the humidifier.
  • Ultrasonic Humidifiers: These cool-mist humidifiers use ultrasonic vibrations to create water vapor.
  • Impeller Humidifiers: Impeller humidifiers have a disc that throws the water against a fan that breaks it up into water vapor.
  • Steam Vaporizers: Steam vaporizers, also called vaporizers, have a heating element that warms the water to create steam. That steam cools slightly before leaving the unit to humidify the air. These models are often used in cold climates to help maintain warmer temperatures.

Many people wonder if they need a warm-mist or cool-mist model. Humidifiers rated to the same square footage offer equal humidifying abilities. However, their means of doing so can affect your home differently. Warm-mist humidifiers help maintain warmer temperatures. They’re a great addition to a home in a cool climate or for use in the winter months. They’re also more resistant to bacteria and mold growth because heat kills that growth. However, if these models fall over, the water is hot enough to scald. For that reason, warm-mist humidifiers aren’t recommended for homes with children or pets.

Cool-mist humidifiers aren’t as energy efficient as warm-mist models, and they are more prone to problems with bacteria and mold. However, they don’t post a burn or scalding hazard like a warm-mist model. Their lack of a heating element typically makes them less expensive too.

The Right Humidity Levels

Once you’ve decided on a humidifier type, you want to make sure the humidifier keeps the humidity at the right level. The best humidity levels vary by season, weather, and geographical location. All these environmental conditions affect the relative humidity, which is the amount of water vapor the air can hold at a given temperature.

A safe, comfortable humidity level usually falls between 30 to 50 percent humidity. You may find as you use a humidifier more regularly that you prefer a high or low humidity, and you can make adjustments to keep the humidity levels where you are most comfortable.

Some humidifiers have built-in hygrometers that measure and display the humidity level for you. It may even have an auto mode that regulates the humidity level on its own. It may slow or speed up the fan according to a preset humidity level. If the humidifier doesn’t have a hygrometer, they’re inexpensive to purchase separately and are an important part of maintaining a safe home environment.

Too Much of a Good Thing

High humidity can promote mold, mildew, and bacterial growth in a single room, on carpet, curtains, and furniture. Growth of unwanted visitors can toss all of a humidifier’s benefits out the window. Consequently, too much humidity can cause the nasal congestion and sore throat you’re trying to relieve.

We’ve already discussed the importance of a hygrometer in maintaining healthy humidity levels. You can also control humidity levels by doing your homework before you buy. Humidifiers are rated for rooms of a specific square footage. A humidifier kept in a room that’s too small will easily over humidify it even if it’s running on the lowest setting. Match the humidifier’s output to the room size, and you’ll have a head start on managing humidity levels.


Can I use tap water in a humidifier?

The problem with tap water is mineral buildup. This buildup leaves white rings in the humidifier’s water tank and can clog some of the components. Minerals can also leave powdery white dust on furniture or even people if it’s kept near a bed at nighttime. Distilled water goes through a purification process that removes many of the problem-causing minerals. Using this type of water can mean less maintenance for you and longer life for the humidifier.

How often should I change the water?

Water should be changed every day along with daily cleaning. Proper cleaning reduces the chances of mold and bacteria and makes sure you get the humidifier’s full health benefits.

Do humidifiers have filters?

There are filtered and filter-free humidifiers. Filters can capture bacteria and allergens. However, eventually, they get saturated and need replacement. Depending on how often you run the humidifier, filters may need to be changed every three months. The price of replacement filters adds up over time. Sometimes that can make these models more expensive over the lifetime of the humidifier.

Filter-free models have easier maintenance and cost less over time, but their lack of filter is one less barrier for bacteria.

A Final Note

Humidifiers are a great way to manage the humidity levels in your home. They can do everything from help control common allergens to reducing static electricity. The best humidifier for you will depend on how much moisture you need in your home, the size of the room in which you want to use it, and your climate. Proper use, cleaning, and maintenance will ensure that you get all of the benefits these devices have to offer.


Feeling Lucky?

Sign up for updates and
exclusive deals.