Humidifier Buying Guide

Whether you are looking to relieve dry skin, manage a respiratory condition, or alleviate the symptoms of the common cold, a humidifier is an excellent solution for improving your indoor comfort and overall health. Unlike dehumidifiers, which lower your indoor humidity by extracting moisture from damp, muggy air, humidifiers increase your indoor humidity by injecting moisture into dry air in the form of an invisible mist. Humidifiers are most often used in the wintertime to help ease the physical discomforts caused by winter heating. However, they can also be operated year-round to help alleviate respiratory problems and colds as well as to keep certain household items in good condition. For easier accessibility to the sections in this article, use our topic list below:

• Why Do You Need a Humidifier?
• Measuring Your Humidity
• Choosing Size and Capacity
• Determining the Right Type
• Weighing the Cost
• Convenience Features
• Maintenance and Care
• The Least You Need To Know

Why Do You Need a Humidifier?

There are many reasons why you would benefit from using a humidifier. Most popularly, humidifiers are used in colder months to combat dry air and to reduce the negative effects it can have on your health. When the air outside grows cold during the fall and winter seasons, it’s our common practice to retreat indoors and crank up the heat. But while heating systems do a good job of warming the air, they actually decrease the humidity level of your air drastically. Dry indoor air can lead to:

• Dry sinus passages
• Bloody nose
• Cracked lips
• Sore, scratchy throat
• Dry, scaly skin
• Aggravated respiratory ailments

Excessively dry air can also affect your home’s interior. For example, dry conditions can wreak havoc on wallpaper, causing it to peel at the edges. Wood floors and wood furniture pieces may lose moisture and contract, leading to unsightly cracks, warps, and separations. Moreover, static electricity can flourish, causing unexpected and painful shocks as well as potential damage to electronic equipment. Regularly running a humidifier to boost the moisture content in the air will help eliminate these problems.

Humidifiers are also used to help manage respiratory ailments caused by asthma flare-ups, allergies, colds, sinus infections, congestion problems, and other illnesses. The moisturizing mist that a humidifier adds to the air soothes your breathing passages, making it easier for air to pass through and for mucus to drain. Some models even feature special medicine cups that allow you to blend in respiratory medications, which are released into the air along with the mist.

Additionally, humidifiers can be used to protect certain belongings such as musical instruments and fine art from irreparable damage. Just as hardwood floors and wood furniture can lose their moisture and crack, so can the body of a prized piano or the surface of an expensive painting.

Measuring Your Humidity

Maintaining balanced indoor humidity throughout the year is an integral part of a comfortable and healthy environment. According to the Mayo Clinic, the ideal humidity level within a home or building is between 30% and 50%. Humidity that measures higher than 50% fosters the growth of bacteria, dust mites, mold, and other symptom-aggravating allergens. In addition, this kind of damp and muggy environment may develop an unpleasant, musty odor and cause wood to rot, walls to stain, and paint to peel. On the flip side, environments with humidity measuring lower than 30% will leave you susceptible to dry air’s adverse health effects and your interior furnishings vulnerable to damage.

To learn more about humidity and the importance of monitoring it indoors, read our article Understanding Relative Humidity.

To achieve balanced indoor humidity, you need to first determine what your actual humidity level is. Nowadays, measuring the humidity within your indoor space is a simple and quick process that can be performed using an inexpensive digital hygrometer, such as an Vicks Healthcheck Digital Hygrometer or an Acu-Rite humidity sensor. These battery-operated devices display accurate readouts of the humidity level and temperature. They can often be wall-mounted for continual use and may include extra features such as Celsius/Fahrenheit conversion, large internal memories, optimal humidity level alerts, and backlights for easy reading.

Some humidifier models, such as the Essick Air 3D6-100 Mini Console Humidifier, include built-in hygrometers as well as humidity control sensors known as humidistats to help you precisely measure and adjust your home’s humidity.

Choosing Size and Capacity

Humidifiers come in a variety of sizes and capacities to suit your home or building’s needs. Each unit is rated for an area of coverage in square feet or by estimated room size. A humidifier’s output capacity is measured in gallons of moisture per day.

When shopping for a humidifier, you should also consider the tank size and moisture output capacity. Tabletop and console humidifiers hold different amounts of water and produce varying levels of moisture. Choosing among them is a simple question of convenience. Take a moment to think about how often you want to refill your humidifier. Are you comfortable refilling it daily (portable), every few days (console), or not at all (whole house)?

For example, the 2-gallon-size Enviracaire EWM-211D Warm Mist Humidifier produces roughly 2.4 gallons of moisture to cover a small- to medium-sized room over a 24-hour period. That means if you run the unit nonstop, you’ll need to refill the water reservoir every day. The Essick Air Credenza-Style Humidifier disperses 12 gallons of water per day to cover about 2,500 square feet. This unit needs refilling less often because of its 5.2-gallon water tank. However, refilling this larger tank might prove to be more physically demanding. Whole house humidifiers, like the Honeywell HE220 Whole House Bypass Humidifier, never need refilling because they draw water directly from the water supply in your home or building.

When shopping for a humidifier, be sure to look for the coverage area rating, the water container size, and the maximum output capacity listed in the product’s specifications.

Determining the Right Type

Humidifiers add moisture to the air in different ways, and each type carries its own advantages and disadvantages. A cool mist humidifier generally covers larger areas and uses less electricity than other types of humidifiers. Yet, because these systems contain more moving parts, they are often noisier than other models, which may be a turnoff. Popular types of cool mist humidifiers include:

• Evaporative humidifiers, the most popular type, use a wick filter that absorbs water from the unit’s reservoir. An internal fan then blows room air through this filter, which causes the absorbed water to evaporate as a cool, invisible mist. The wick filter has an added benefit of helping to remove impurities from the water before it is released into a room. Bypass, flow-through, and drum humidifiers usually work in this fashion.


• Impeller humidifiers employ a rapidly spinning disc that propels water through a diffusing screen. When the water travels through this screen, it is broken down into tiny droplets and released into the air as a fine mist. Air washer humidifiers also use impeller humidification technology.

A warm mist humidifier uses a heating element to heat the water and release it into your room as a warm, comfortable mist. Because these units boil the water beforehand, they use a little more electricity than cool mist models, which might make your energy bill increase slightly. Health-wise, warm mist humidifiers carry an advantage of killing waterborne bacteria or mold during the boiling process. This keeps allergens from entering the air—and your lungs. However, there is a small risk of burns associated with the heating element, so a warm mist humidifier may not be a good choice for a child’s room or for areas where pets move around frequently. Warm mist units typically cover smaller areas than cool mist models, but they are often less noisy because they don’t require a fan. Popular types of warm mist humidifiers include:

• Steam humidifiers boil water and release it into the air as a warm steam. When used in a cold climate, these models can help make the air feel warmer temporarily without requiring you to adjust your thermostat.


• Vaporizers use electrodes to heat water and transform it into a steam vapor. These units feature very basic designs with no-frill controls and are often considered less powerful than steam humidifiers. Vaporizers are good units to use if you plan to blend respiratory medications in with the steam. Many warm mist humidifiers feature optional medicine cups for this purpose as well.

Newer to the market, the more modernly designed ultrasonic humidifiers—including Air-O-Swiss humidifiers—are available in both cool and warm mist versions. These models use high-frequency sound waves to vibrate a metal diaphragm to an ultrasonic frequency. This motion creates small water droplets that are released from the humidifier as a fine fog. Ultrasonic humidifiers are the quietest units on the market because they produce sound waves at a frequency higher than we can hear.

Choosing the right type of humidifier depends mainly on your comfort needs, your budget (more on this in the next section), and your willingness to perform maintenance. Ask yourself these questions:

• Do you want to feel warm mist or cool mist? In the long-run, all humidifiers can make your indoors feel warmer by increasing the humidity. However, some models may temporarily affect the temperature of your surroundings. Warm mist humidifiers have a tendency to make your space feel slightly warmer while cool mist models disperse moisture at room temperature.


• How important is the noise factor? Warm mist humidifiers are typically less noisy than cool mist humidifiers because they don’t use a fan. Ultrasonic humidifiers are even quieter, making them great choices for bedrooms and other quiet environments.


• How much maintenance is required? Evaporative humidifiers, which use a wick filter, require a filter replacement or a thorough filter cleaning (for units with reusable filters) on a regular basis. Units that operate without a filter simply need to undergo regular maintenance. If your humidifier is equipped with a demineralization filter, a germ-reducing insert, or an ultraviolet lightbulb, you'll also need to replace these components at the manufacturer's recommended intervals.

Weighing the Cost

Portable room humidifiers are the least expensive humidifiers to purchase. These models are priced anywhere from $20 to well over $200 and beyond, depending on their sizes and features. Cool mist humidifiers may have less of an impact on your power bill because, unlike warm mist units, they do not require extra electricity to heat the water. However, the power requirement of a warm mist humidifier is comparable to the electricity needed to heat a teapot, so you may not even notice a difference.

Console humidifiers are priced a little higher. These models can run from around $100 upwards to $250, and because they’re larger, they will use more power throughout the day. Whole house in-duct humidifiers, while they may be a bit pricier than console humidifiers, are the most cost-effective and energy-efficient humidifiers to use in the long-run.

Convenience Features

Today’s humidifiers include a variety of features and controls that make operation more convenient. Some notable ones to look for include:

• Built-In Hygrometer/Humidistat — A hygrometer measures the amount of moisture within a space and reports it as a percentage, so you will always know if your home’s humidity is within the recommended range. A humidistat works in the same manner, but it has the power to automatically turn the unit on and off in order to maintain a preset humidity level.


• Variable Speeds — Selecting from more than one operating speed lets you control a humidifier’s moisture output and limit power usage. Multiple speeds also help you adjust the noise level.


• Automatic Shutoff — Some humidifiers feature automatic shutoff controls that turn off the unit when the water reservoir empties. This is important for safety reasons as well as for energy efficiency.


• Indicator Lights — These lights alert you when the humidifier’s water supply is running low, when filters or other parts need to be replaced, or when its time to clean your humidifier.


• UV Germicidal Light — An ultraviolet humidifier features internal ultraviolet (UV) germicidal lights that kill waterborne germs, bacteria, and mold before the water is released as a mist. This feature is especially beneficial to allergy- and asthma-sufferers.


• Air-Cleaning Pre-Filter — Also helpful for allergy-sufferers, this filter helps rid inbound air of impurities such as dust particles, pollen, pet dander, and mold before it is humidified and released.


• Digital Control Panel — While analog controls are useful, they may not give you the accuracy of a digital control panel. Digital measurements let you know exactly where your humidity falls and help you make precise changes.


• Demineralization Cartridge - Sometimes using hard water to fill your humidifier can lead to unhealthy white dust, which develops as the hard water's elevated mineral content is dispersed into the air. Overtime, breathing white dust can aggravate existing respiratory ailments and cause new ones to develop. A demineralization cartridge removes mineral content from your water to reduce the risk of white dust.

Maintenance and Care

While humidifiers make your indoor air healthier and more comfortable, these units can quickly become health hazards if they are not maintained properly. All humidifiers, especially warm mist units, need regular cleaning and disinfection in order to curb bacteria, mold, and mineral growth. If this is not performed, impurities can be released into the air you breathe. Overtime, breathing contaminated air may aggravate allergies and asthma, trigger flu-like symptoms, and contribute to a lung infection.

As a rule of thumb, if you use your humidifier on a daily basis, you should clean it at least once a week. Follow the manufacturer’s instructions in your product manual for how to clean and care for your unit. To help reduce the amount of mineral deposits that may develop, consider using distilled or de-mineralized water instead of tap water in your humidifier. Remember to change any filters and special parts on a regular basis as well. Read our article Tips for Maintaining Your Humidifier for more information.

The Least You Need To Know

• Humidifiers help boost the moisture content in your indoor air to help ward off uncomfortable health problems and damage to your interior.


• Tabletop humidifiers cover single rooms. Console humidifiers cover multiple rooms or large areas. Whole house units connect to your heating and cooling system and cover a whole home or building.


• Shop for a humidifier based on the square footage or estimated size of the area you want to humidify. Next, consider water tank size and moisture output.


• Cool mist humidifiers cover large areas, but are often noisy because they have more moving parts.


• Warm mist humidifiers use more electricity to heat water and release it as a steam. However, they are quieter and have the added advantage of killing waterborne impurities with heat.


• Ultrasonic humidifiers are the quietest units on the market.


• Tabletop humidifiers are the least expensive units to buy, followed by console humidifiers and whole house humidifiers. Whole house units remain the most energy-efficient when operating.


• Look for helpful convenience features such as built-in humidity meters, variable speeds, and automatic shutoff controls — among others — when examining a humidifier.


• Regularly clean your humidifier to reduce the buildup of minerals and bacteria, which can be released into the air you breathe. Replace filters and other parts as needed.

Still Have Questions?

For more information on specific humidifiers and other ways to improve your indoor air, please review our extensive product listings and visit our Learning Center for helpful information. Not sure what’s best for you? We can take the guesswork out of decision-making. Contact our product experts toll-free at 1 (800) 934-9194. We want to help make your environment a healthy one.