Editing Humidifier (section)

==Electric humidifiers==

===Evaporative humidifiers ===
An "evaporative", "cool moisture", or "wick humidifier", consists of just three basic parts: a reservoir, a wick, and a fan.

The wick is made of a [[Porous medium|porous material]] that absorbs water from the reservoir and provides a larger [[surface area]] for it to evaporate from. The fan is adjacent to the wick and blows air onto the wet wick to aid in the evaporation of the water.  Evaporation from the wick is dependent on [[relative humidity]]. A room with low humidity will have a higher evaporation rate compared to a room with high humidity. Therefore, this type of humidifier is partially self-regulating; as the humidity of the room increases, the water vapor output naturally decreases.

These wicks become [[Mold (fungus)|mold]]y if they are not dried out completely between fillings, and become saturated with mineral deposits over time.  They regularly need rinsing or replacement; if this does not happen, air cannot pass through them, and humidifier stops humidifying the area it is in and the water in the tank remains at the same level.

Evaporative humidifiers function similarly to [[evaporative cooler]]s.

===Impeller humidifiers ===
[[Impeller]] humidifiers (a type of cool mist humidifier) are usually noisier than others.  It uses a rotating disc to fling water at a diffuser, which breaks the water into fine droplets that float into the air. The water supply must be kept scrupulously clean, or there is a risk of spreading bacteria or mold into the air.

===Ultrasonic humidifiers ===
[[File:Ultrasonic Cool Mist Humidifier.jpg|thumb|Ultrasonic Cool Mist Humidifier]]
An ultrasonic humidifier uses a ceramic diaphragm vibrating at an [[ultrasound|ultrasonic frequency]] to create water droplets that silently exit the humidifier in the form of cool fog. Usually the mist gets forced out by a tiny fan, while some ultra mini models have no fans. The models without fans are meant mainly for personal use. Ultrasonic humidifiers use a [[piezoelectric transducer]] to create a high frequency (1-2&nbsp;MHz<ref>{{cite journal |last1=Rodes |first1=C. T. R. G |title=Measurements of the size distribution of aerosols produced by ultrasonic humidification. |journal=Aerosol Science and Technology |date=1990 |volume=13 |issue=2 |pages=220–229|doi=10.1080/02786829008959440 |bibcode=1990AerST..13..220R |doi-access= }}</ref>) mechanical oscillation in a film of water. This forms an extremely fine mist of droplets about one micron in diameter, that is quickly evaporated into the air flow.

Unlike the humidifiers that boil water, these water droplets will contain any impurities that are in the reservoir, including minerals from [[hard water]] (which then forms a difficult-to-remove sticky white dust on nearby objects and furniture). Any pathogens growing in the stagnant tank will also be dispersed in the air. Ultrasonic humidifiers should be cleaned regularly to prevent bacterial contamination from being spread throughout the air.

The amount of minerals and other materials can be greatly reduced by using [[distilled water]]. Special disposable demineralization cartridges may also reduce the amount of airborne material, but the EPA warns, "the ability of these devices to remove minerals may vary widely."<ref name="epa" /> The mineral dust may have negative health effects.<ref>{{Cite web|last=Willis|first=Katie|title=Using tap water in an ultrasonic humidifier may be polluting your air: study|url=https://www.ualberta.ca/folio/2020/11/using-tap-water-in-an-ultrasonic-humidifier-may-be-polluting-your-air-study.html|access-date=2022-01-24|website=www.ualberta.ca|language=en}}</ref><ref>{{Cite journal|last1=Yao|first1=Wenchuo|last2=Gallagher|first2=Daniel L.|last3=Dietrich|first3=Andrea M.|date=2020-12-01|title=An overlooked route of inhalation exposure to tap water constituents for children and adults: Aerosolized aqueous minerals from ultrasonic humidifiers|journal=Water Research X|language=en|volume=9|pages=100060|doi=10.1016/j.wroa.2020.100060|pmid=32793876|pmc=7408721|bibcode=2020WRX.....900060Y |issn=2589-9147}}</ref>  Wick humidifiers trap the mineral deposits in the wick; vaporizer types tend to collect minerals on or around the [[heating element]] and require regular cleaning with [[vinegar]] or [[citric acid]] to control buildup.

===Steam Humidifiers===
Steam humidifiers, or warm mist humidifiers, are equipped with a [[heating element]].

A medicated inhalant can also be added to the steam vapor to help reduce cough. Vaporizers may be healthier than cool mist types of humidifiers because steam is less likely to convey mineral impurities or microorganisms from the standing water in the reservoir.<ref name="epa">{{cite web |url=https://www.epa.gov/sites/production/files/2014-08/documents/humidifier_factsheet.pdf |title=Indoor Air Facts No. 8: Use and Care of Home Humidifiers |publisher=[[United States Environmental Protection Agency]] |year=1991 |archive-url=https://web.archive.org/web/20210323094134/https://www.epa.gov/sites/production/files/2014-08/documents/humidifier_factsheet.pdf |archive-date=23 March 2021 |url-status=live}}</ref> However, boiling water requires significantly more energy than other techniques. The heat source in poorly designed humidifiers can overheat, causing the product to melt, leak, and start fires.<ref>{{cite web |url=http://www.cpsc.gov/cpscpub/prerel/prhtml06/06215.html |archive-url=https://web.archive.org/web/20080905034103/http://www.cpsc.gov/cpscpub/prerel/prhtml06/06215.html |archive-date=2008-09-05 |title=Humidifiers Recalled for Fire Hazard |url-status=dead }}</ref>

==== Tanks ====
The water is usually supplied by manually filling the unit on a periodic basis.

Top fill: A top fill tank has a hole at the top to make it convenient to refill the tank on daily basis.

Bottom fill: Bottom filled humidifiers has removable water tank, often attached with a replaceable demineralization filter. Both the cap and the filter are often universal, which means that they can be switched between many tank cap humidifiers.
[[File:دستگاه_بخور_سرد.jpg|thumb|An ultrasonic humidifier with a bottom filled tank that has a replaceable demineralization unit (see inside bottom)]]

Tank cap-based humidifiers are more inconvenient to fill than top fill tanks, because the demineralization filter has to be unscrewed and screwed back on a daily basis. Also, water drops from the tank attachment may get in contact with the hygrometer, which will make it harder to operate properly if they are not operated with caution.

=== Cleaning ===
Ultrasonic wave nebulizers trap the mineral deposits over time, even if filters are used, and require cleaning with [[vinegar]] or [[citric acid]] to control buildup. It is easy to remove the buildup from the nebulizer in humidifiers with removable base parts. Other models must be screwed. Some models require monthly maintenance, while other models may run for years unmaintained.

==== Activated charcoal filter ====
Some humidifiers have an [[Activated carbon|activated charcoal]] filter to reduce contaminants.

==== Demineralization filter ====
Humidity with mineral deposits build up on furniture, and static objects like computer monitors, TVs, etc.

Most models with heating elements come with replacement demineralization filters (cartridges, or plastic foam, for the tank, and fabric near the heater in the reservoir) to reduce the amount of minerals entering the system. The cost of these filters is about $10–15 per cartridge or 10-pack for plastic foam, or fabric filters. Cartridges may last for 6 months, and plastic foam/fabric filters may last one month, if the humidifier is frequently used. Cartridges can be used for most humidifiers, but some models have a proprietary format.

Some humidifiers (for example, some cold mist humidifiers) don't come with any filters at all.

Clogged filters should be replaced when they cannot deliver water, which is indicated with a "no water" icon/alert signal in modern humidifiers. A manual way to figure out if a filter is clogged is to shake it, if the content of it (even if wet) doesn't move around, then it's unlikely that sufficient water will pass through.

==== Ultraviolet germicidal irradiation (UVGI) ====
Some humidifiers have an integrated [[ultraviolet germicidal irradiation]] (UVGI) feature.

==== Water ionizer ====
Some humidifiers have an integrated [[water ionizer]].

===Maintenance===
[[File:Sony_VPL-HS1_-_Delta_Electronic_Toto_TYF_300-J01-92424.jpg|thumb|left|A typical centrifugal fan found inside ultrasonic humidifiers.]]

A [[torx]] screwdriver is often needed to open [[consumer electronics]].

Humidifiers with a [[centrifugal fan]] may become noisy due to build up which cannot effectively be removed with vinegar for example. However, the fan can be replaced, and the model name of the fan and its specifications can be figured out by disassembling the humidifier and detaching it.