Humidifiers 101

Benefits of Humidification

Humidifiers gently disperse moisture into your home environment, alleviating dry air and making your home more comfortable throughout the year. In arid regions or during the dry winter months, dry indoor air can be detrimental to your home and to your family’s well-being:

What Humidifiers Do and Why This Is Important

  • Add moisture in dry months and maintain a healthy level of humidity throughout the year.
  • Relieve scratchy throat and hay fever symptoms: moisture helps relieve dry skin and eyes, coughs, and scratchy throats, helping you breathe better and sleep more comfortably.
  • Reduce static electricity: beneficial to people, computers, and other home electronics.
  • Maintain your home’s interior: consistent moisture level protects wood floors, plant life and even furniture, musical instruments, paint, and wallpaper.
  • Increase freshness: adding humidity can increase the freshness in your home, alleviating stale “indoor air.”
  • Lower energy bills: moist air feels warmer than dry air, so you can set your thermostat lower while still feeling warm and comfortable.

Types of Products

Cool Mist

Cool Mist (Evaporative Wick) humidifiers gently disperse cool, invisible mist into the air. Dry air is pulled into the system, passing through a saturated wick filter. Moisture is fan-evaporated into the air while sediment, minerals and other impurities are trapped in the filter. The result is clean, pure, refreshing mist. These safe and effective humidifiers work well in larger rooms and the cool, refreshing mist is comforting in arid climates. 

Warm Mist

Warm Mist models produce warm, soothing visible mist for added comfort during cold winter months. A gentle boiling process traps impurities, releasing clean warm vapor into the air. Many models but not all offer humidistat technology and medicine cups to disperse inhalants for added relief. 


Ultrasonic humidifiers produce fine, lighter mist that quickly disperses humidity into the room. In these models, a transducer vibrates water at ultrasonic speed to break it down, producing pure, refreshing visible cool mist. Ultrasonic models are quiet, refreshing, and low-maintenance. 


Vaporizers produce warm, soothing vapor through a boiling process that removes impurities from the water before releasing clean, fresh moisture into the air. Vaporizers are compact and cost-effective, and do not include a removable tank.

Additional features: Look for these added features on your Holmes® humidifiers.

Humidistat – a humidity thermostat measures the moisture in the air and automatically disperses moisture to achieve the setting you select.

Contains an Antimicrobial Product Protection Additive – This information is based upon standard laboratory tests and is provided for comparative purposes to substantiate antimicrobial activity for nonpublic health applications. Antimicrobial additive is not designed to protect users from disease causing microorganisms. Antimicrobial additive inhibits the growth of microorganisms that cause stains and odors. Antimicrobial action limited to product surface.

Filter Change Reminder – an indicator light takes the guesswork out of filter replacement and ensures optimal air quality over time.

Holmes® Filters with CarbonX – these filters include odor-absorbing carbon that helps remove household odors as they disperse moisture into the air.

Arm and Hammer® – Select filters are treated with Arm & Hammer®*(6) baking soda to help absorb and eliminate household odors. (US only)

Care and Cleaning

  • Humidifiers provide comfort by adding moisture to dry, heated indoor air. To get the most benefit from the humidifier and to avoid product misuse, follow all instructions carefully, specifically the operation, care and maintenance guidelines.
  • Please note this is an electrical appliance and requires attention when in use.
  • Cleaning your humidifier every one or two weeks, depending on the water conditions is important in order to maintain efficient, healthy, odor-free operation. Water quality varies widely and, combined with build-up of mineral scale in your humidifier, may under certain conditions promote the growth of micro-organisms in the water tank.

Before cleaning, please note the following:

  • Do not use soap, detergents, abrasives, gasoline, glass or furniture polish, or boiling water to clean any part of your ultrasonic humidifier. These will interfere with the proper operation of your unit and may affect its appearance.
  • Do not use sharp or metal objects to clean mineral deposits in the reservoir. Contact with sharp objects can result in damage to the plastic.
  • Mineral deposits should be soaked for up to 20 minutes in a household cleanser or in plain vinegar and water to help with their removal.

Daily maintenance:

  • Before cleaning, set the humidity control switch to the Off position and unplug the unit from the electrical outlet. Lift off the tank of the humidifier.
  • Carry the base and the tank to the sink, then drain and rinse the base and tank thoroughly to remove any sediment or dirt. Wipe clean and dry with a clean cloth or paper towel.
  • Refill the tank with cool tap water as instructed in “Operating Instructions”. Do not over fill.
  • If moisture forms on walls or window, turn the humidifier off.