Which humidifiers are the quietest? 

Ultrasonic humidifiers are the quietest humidifiers available, and the ideal choice when noise level is a concern (if you are a light sleeper). In general, a warm moisture humidifier will be much quieter than a cool moisture evaporative humidifier. Warm moisture models release steam vapor into the air without the use of loud, powerful fans; instead of a loud fan, you will hear a quieter boiling/gurgling noise caused by the heating of the water into steam.  Cool moisture evaporative humidifiers use a fan to blow air through an evaporative wick filter, which makes more noise than a warm moisture humidifier. The amount of fan noise depends on the fan speed setting, so a humidifier with many fan speeds offers you more flexibility in choosing the best level of humidity output and noise level for your needs. In general, when running on the lowest fan speed, cool moisture evaporative humidifiers produce a quiet background "white noise", which many people find helpful when sleeping.




Do I need to replace filters, and if so, how often?

Most evaporative cool moisture humidifiers use replaceable wick filters, and these should be changed every 1-2 months on average (wick filter life varies depending on your specific humidifier model, frequency of use, and your water's mineral content). Most wick filters are coated with a special antimicrobial coating designed to slow the growth of mold on the filter. Warm moisture humidifiers do not use wick filters at all but will need to be cleaned regularly to remove hard water mineral buildup. Most ultrasonic humidifiers use optional demineralization cartridges, which help reduce mineral deposits found in tap water which can exit the humidifier in the form of white dust.




What is white dust, and should I be concerned about it?

White dust is a byproduct of minerals found naturally in water, which can sometimes be released into the air during the humidification process. White dust, which can be a nuisance but is not harmful, may settle on surfaces and furniture near the humidifier. It is easily cleaned just as you would normally dust. Warm moisture (steam vaporizers) and evaporative cool moisture humidifiers do not release any white dust into the air. The only types of humidifiers that can potentially release white dust are ultrasonic humidifiers and cool mist impeller humidifiers. Many ultrasonic humidifiers come with an optional demineralization cartridge designed to trap minerals before they can become airborne, thus reducing white dust. You can also use ultrasonic humidifier water treatment to reduce white dust. The amount of white dust you may experience will vary depending on the mineral content of your water supply. If white dust is a concern, you can use distilled water in your humidifier instead of regular tap water. Distilled water has very low mineral content and will not produce white dust. For other types of humidifiers, using distilled water will also reduce the amount of time you will need to clean your humidifier, and will help prolong filter life.




How often do I need to clean my humidifier?

Your humidifier should be cleaned regularly to prevent the growth of mold, mildew, fungi, and bacteria. These organisms can thrive in standing water that is left inside your humidifier for more than a couple of days. It is best to empty and refill your humidifier on a daily basis, or keep your humidifier running throughout the day, to avoid having standing water sitting in your humidifier. Regular cleaning is recommended at least once every 1-2 weeks. The product manual that comes with your humidifier will have specific instructions as to the best way to clean and maintain your humidifier. Please follow your specific humidifier's cleaning instructions carefully to ensure the most healthy and efficient operation of your humidifier. Humidifier cleaning solution can help you clean and prepare your humidifier for efficient operation by removing lime scale buildup and sludge deposits.




What does humidifier room size mean, and which size humidifier is best for me?

Most humidifier manufacturers publish a recommended room size (in square feet) for each model they produce. A recommended room size is not a guarantee that the humidifier will be able to raise the relative humidity (RH) level of any particular room size to any specific RH level. Room size recommendations should be used only as rough guidelines when shopping for a humidifier, as these recommendations are subjective, are based on ideal environmental conditions, and can vary from manufacturer to manufacturer. Each manufacturer bases their recommended room sizes on the maximum amount of moisture the humidifier is capable of producing per day, assuming the humidifier is operating in perfect environmental conditions, with the humidifier constantly running on its maximum speed setting.

Once a humidifier adds moisture to a room, there are many factors at work to dry out the air again. These factors, which vary from room to room, day to day, even hour to hour, include: Outdoor and indoor temperatures, indoor heating level and type of heat (forced air, baseboard, wood stove, etc), location of air ducts, location and insulation of windows/doors, ceiling height, how well the room is closed off and sealed, etc. The maximum RH level possible in your room depends on your unique room environment.

We choose to publish manufacturer's recommended room sizes because that is how most humidifiers are sold today. However, after years of our own testing of every humidifier we sell in real world conditions, we have found that you will get the best performance by using the highest output humidifier possible that will fit in your room and budget.




What is humidifier output?

Often confused with humidifier capacity, humidifier output refers to the maximum gallons of water the humidifier is capable of producing per day, and is the best way to compare the effectiveness of various humidifiers. Humidifiers can vary in output anywhere from 1 to 14 gallons per day (for example, a humidifier with an output of 10 gallons per day will be capable of producing 5 X more moisture than a humidifier with a 2 gallon output). Regardless of a humidifier manufacturer's recommended room size, two humidifier models that each have an output of 4 gallons per day will be equally effective. While recommended room sizes can give you a general idea of which humidifiers to consider, a more useful and accurate piece of information is the humidifier output, which allows you to more easily compare different humidifiers and their relative effectiveness.




What is capacity, and how often will I need to refill my humidifier?

Humidifier capacity is the maximum amount of water the humidifier can hold at any one time, and varies from 0.5 to 6 gallons, depending on the size of the humidifier. Output is the maximum amount of water the humidifier can add into the environment per day, and nearly all humidifiers have a higher output than capacity. The frequency with which you will need to refill your humidifier depends on your humidifier's tank capacity relative to output, and the speed setting you select. If your humidifier has a 5 gallon output per day, and it has a holding capacity of 2.5 gallons, you will need to refill the humidifier every 12 hours in order to obtain the full possible 5 gallon maximum output per 24 hour period. The higher the tank capacity relative to the output, the less often you will need to refill the humidifier. In addition, you can go longer between refills if you run your humidifier on a lower speed, or if you do not run it constantly 24 hours per day.

Most humidifiers have a removable water tank which is filled at a sink or bathtub and then placed onto the humidifier base. As the water in the base of the humidifier is used, more water from the tank will be released into the base. Some humidifiers have an automatic shut-off feature which will turn the humidifier off once the water needs to be refilled. There are also some humidifiers with a "top-fill" (or front-fill) design, which eliminates the need for the removable water tank. With these humidifiers, you pour water directly into the top of the humidifier using a pitcher, cup, or any other water container. This can be helpful for those with arthritis or who may have trouble lifting and carrying a water tank.



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