Top Evaporative Vornado Vortex	Top Warm Mist Slant/Fin GF-220	Budget Picks Honeywell HWM-530  (E)	Switch Hitter (Warm/Cool) Air-O-Swiss 7135	Top Console Style Bemis H12 300

What is "white dust"?

White dust, or white powder, is frequently mentioned in articles about humidifiers. All it means is that when the water has a high mineral content, fine white dust settles on furniture in rooms where you use the humidifier or collects in the humidifier. Some machines have built-in filters or demineralizers to deal with this problem; sometimes they can be purchased separately. The problem can also be avoided by

Humidifier Types

There are two basic types of humidifiers: warm mist and cool mist. Each of these can be subdivided further.  Most humidifiers are small and portable and provide coverage for a room, which is usually sufficient for the average consumer needs. Another option is the console-style  humidifier. Console-style humidifiers are meant for large coverage, often for humidifying an entire apartment or house.

Warm Mist Humidifiers

Warm mist humidifiers  produce warm steam by boiling water and then allow the steam to cool before releasing it into the air. Pros Whisper quiet: They are usually quieter than cool mist humidifiers when on low settings, but some boiling and gurgling can be heard while set to high. No germs: They produce cleaner air because they use boiled, distilled water. Warmth: Warm mist can make a room feel warmer without raising the thermostat. Speed: Warm mist disperses and makes the atmosphere feel more humid more quickly than cool mist. Kid-friendly: Recommended for nurseries by most pediatricians. Cons Regular Maintenance: Replacement filter pads  need to be bought regularly, thus increasing long-term costs. Energy Usage: Since these models heat the water, they cost more to run per year.

Vaporizers  put out warm steam that isn't cooled before releasing it into the air. Most of the pros and cons of other warm mist humidifiers apply here, with the following additions. Pros Can add certain medications or herbal cold remedies for quick intake and respiratory relief. Cons Vaporizers usually don't cool the steam, so they are even more likely to cause burns.

Cool Mist Humidifiers

There are three distinct types of cool mist humidifiers: evaporative, ultrasonic, and impeller. They all put out a cool mist without any risk of burn from hot vapor.

Evaporative humidifiers  put out a cool mist by blowing air through a moistened wick or filter. Pros The wick or filter retains any particles in the water and may be treated to kill bacteria. Efficient and reliable. Most commonly available type. Cons Noise: They are often much noisier than warm mist humidifiers. High Maintenance: Costs are higher because the wick filters need to be replaced often. Furthermore, since the water isn't boiled, bacteria can grow in the tank unless it is cleaned and the water changed regularly.

Ultrasonic humidifiers  Pros High-frequency vibrations, instead of a fan, disperse water droplets. Quiet and efficient. Some Air-O-Swiss models (pictured) can produce both warm and cool mist. Cons Has problems with "white powder" unless distilled water is used. You can also use a demineralization cartridge, but the costs can add up.

Impeller humidifiers  Pros Inexpensive and widely available. Efficient, and require fewer refills. Cons No method of getting rid of bacteria -- if they are in the water, they will be dispersed into the air. Discharges white dust unless a demineralization cartridge is used and changed regularly. Can make rooms feel colder. Not recommended.

Major Considerations

When purchasing a humidifier, there is no single choice that's right for everyone. For some, quiet-running might be the primary concern. Others might prefer the least expensive model, or the most efficient in terms of operating costs. Here are a few tips.

Noise -- Warm mist models are much quieter than evaporative models. Even on the highest setting, they may only make a little bit of gurgling or hissing. Evaporative models, on the other hand, can be quite noisy. Consumer Search says that some may be as loud as small air conditioners. Keep in mind that all console models are evaporative.

Cost -- Usually humidifiers range in price from $50 to $200, depending on their features and capacity. Consoles are more expensive than tabletop models, but warm mist and evaporative tabletop humidifiers are in the same price range ($40-100).

Efficiency --  Evaporative models are much cheaper to run, since they don't heat the water. The smallest ones may cost only a few dollars a year. The largest ones, however, can approach the cost per year of a warm mist humidifier, so it also depends on the size you need.

Coverage Area --  Manufacturers may overstate the area that the model can properly humidify, but for the most part the manufacturers guidelines should at least give you some idea about output of the machine. Console humidifiers are for larger areas than table humidifiers. Warm mist is better for smaller areas, while cool mist is better for larger areas.

Other Considerations

• Construction
• In general, humidifiers are composed of a plastic base with an integrated humidistat; a digital reader for controls and adjustments; a removable water tank; and a filter.
• They come in different makes and models that vary in size, output capacity, and fan speed.
• The majority of humidifiers on the market for home use are portable.

• Maintenance
• The tanks need to be refilled and cleaned regularly.
• Filters require periodic replacement to ensure the machine functions properly.
• You may need to buy replacement wicks or filters as often as every two months. Be sure to factor the cost of replacement parts into your purchase decision.

• Tank Size and Shape
• It varies from one to four gallons.
• Certain models that use two tanks instead of one, increasing overall coverage area.
• Some newer tanks are designed to be easier to fill under a sink. Look for tanks with handles for easy manipulation.

• Fan Speed
• Fan speed plays a large part in the area that can be reached by the humidifier.
• Fans usually have between two and four speeds, but warm mist humidifiers rarely use more than two-speed fans.

• Convenience Features
• For models with timers and a humidistat, a specific time and level of humidification can be accomplished with little effort.
• For optimum simplicity, choose an adjustable digital humidistat with an automatic shut-off option.

• Warranty
• Warranties can range from one to five years.

Other Options

Another, more expensive option (up to $400), are whole-house humidifiers,  which not only create a more humid environment, but also help reduce long-term heating costs. Whole-house systems never need filling, since they take water from your plumbing lines. Filter do not need to be changed as often with these. On the downside, a whole-house humidifier needs to be professionally installed and is not mobile. For more information on these types of humidifiers, check out these sites: Mediawaveonline.com or Smarthome.com.

Related Products

Air Conditioners	Air Purifiers	Dehumidifiers	Electric Fans	Space Heaters

External Links

• All-About-Humidifiers.com-- you guessed it, they're all about humidifiers. Helpful buying advice and descriptions of each type of humidifier.
• ConsumerSearch.com -- reviews and a comparison towards the bottom of the different kinds of humidifiers.
• Allergybuyersclubshopping.com -- humidifiers from an allergy perspective.

International Resources

For this resource in your home country, please see:
FR: Humidificateur